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THE PRACTICE 

OF 

making; and repairing ROADS; 

OF CONSTRUCTING 

FOOTPATHS, FENCES, AND DRAINS; 





THE PRACTICE 



MAKING Sf REPAIRING ROADS ; 



OF CONSTRUCTING 

FOOTPATHS, FENCES, AND DRAINS; 

ALSO, 

A METHOD OF COMPARING ROADS, 
WITH REFERENCE TO THE POWER OF DRAUGHT REQUIRED: 

WLitfi practical ®!)serbattons, 

INTENDED TO 

SIMPLIFY THE MODE OP ESTIMATING EARTHWORK 
IN CUTTINGS AND EMBANKMENTS. 



BY THOMAS HUGHES, ESQ. 

CJVIL EAGINEER. 





CHAPTER I. 

Observations on the necessity for a general Improvement 
of the common Roads. 

While the important main lines of road throughout 
this country have arrived at a degree of excellence 
which may justly entitle them to some share of admira- 
tion, the general condition of our parish and other 
roads can leave no doubt of the fact, that the principles 
of roadmaking, simple and easily derivable as they are, 
from a few obvious truths, are yet but imperfectly 
understood by the surveyors and others, under whose 
management these roads are placed. 

If the principles of roadmaking could only be applied 
with advantage in those cases where ample funds are at 
the command of the surveyor, they would be compara- 
tively of small value to the surveyors of any but the 
great turnpike-roads. That the expenditure of great 
sums of money, however, becomes a necessary conse- 
quence of the determination to obtain a superior road, 
is a notion so erroneous, so dangerous and prejudicial 
to the public interests, that it cannot be too strongly 
guarded against. 

In the construction of roads, as well as in most 
other works of engineering, the greatest amount of 
credit is not, as a matter of course, due to him who 
produces the best kind of road ; because, however excel- 
lent the production may be, it is possible that its cost 
may have been so enormous, that, balancing on the one 

B 



hand the advantage of a good road against the outlay of 
a disproportionately vast sura of money, the engineer 
after all, instead of conferring a boon upon the country, 
may have inflicted a serious evil. This may be con- 
sidered an extreme case, but only because we rarely 
find that trustees are disposed to complain of their 
engineer or surveyor for having expended too much 
money, provided he succeed in constructing a very 
superior road. But, notwithstanding this generosity of 
feeling, we may readily suppose that the parties Avho 
bear the expense of constructing the road, would be at 
least as well pleased to obtain the same kind of road 
at a considerable diminution of cost. The necessity 
of economy in the construction of roads, without at 
the same time sacrificing that excellence which ought 
to form a primary consideration, is, perhaps, more 
urgent now than at any former period in the history of 
this country. The vast and overwhelming competition 
of the railway system, threatens to throw into the shade 
our very best turnpike-roads ; but, at the same time, 
it requires no very profound judgment to discover, 
that the common roads will possess a much better 

) chance of competition with the railroads, if the former 

could be improved to any considerable extent, without 

\ at the same time increasing the expenses of maintenance 

I and of travelling over them. 
// The present condition of our common road system 

'^ appears to call for some improvement, with a degree of 
earnestness not unworthy the attention of an enlightened 
Government. It has now became a question for their 
serious consideration, whether the existing roads are 
to be entirely supplanted, and the vast sums of money 
expended upon them to be sacrificed, without one cfibrt 
to save them from the insatiable rapacity of the all- 
devouring railways. Is it not enough to alarm every 



one interested in the welfare of our ancient roads, to 
reflect, that the least boast indulged in by every one of 
the whole host of railways is, merely, that all the traffic 
of all the roads in its own direction, will at once and 
immediately forsake the old accustomed route, and dis- 
daining the humble paces of eight or ten miles an hour, 
will flock to the railway stations, to enjoy the inesti- 
mable satisfaction of being whirled along at the rate of 
twenty or thirty miles an hour ! 

At the same time, however, that the complacent 
pretensions of railway companies, as we see them 
advanced in their prospectuses, advertisements, and 
reports, are sufficiently monstrous to excite a smile of 
incredulity on the countenance of their warmest well- 
wishers, it is in vain to deny that, as the means of a 
rapid, cheap, and certain communication, every railway 
will, to a great extent, attract the trafiic from the 
neighbouring roads. We may also fully expect to see 
the railway system extended from the main trunks, into 
every town of the least importance where the chances 
of remuneration will at all justify the cost of construc- 
tion. Many places, notwithstanding, will be left without 
the advantage of this rapid and cheap mode of transit ; 
because local circumstances, arising sometimes from 
the difficult nature of the country to be traversed, and 
sometimes from the objections of landed proprietors, 
will often occur to prevent the formation of a railway, 
except at a greater outlay of capital than should ever 
be incurred for the purpose. Under such circumstances, 
it is highly important that the very best description of 
road should be formed to communicate with the railway; 
otherwise, for the towns in question, there is an end to 
all chance of competition with those places which 
possess the advantage of communicating by branch 
railways with the main trunk line. New roads will 

B 2 



also in many cases be formed, in order to obtain a 
ready junction with the great lines of railway ; and of 
course the strongest reasons exist for forming these new 
roads in the most perfect manner. 

Several of the trusts on the London and Holyhead 
read, are at this time actively engaged, at the recom- 
mendation of the Parliamentary Commissioners, in 
canning into effect extensive improvements in the line of 
that road. In place of resigning themselves to the fate of 
losing their traffic in favour of the London and Birming- 
ham Railway, the commissioners of this road are wisely 
endeavouring to raise the travelling to something like 
an equality with that on the railway itself; and it is 
only by adopting such measures, that the system of 
common roads can be expected to stand the shock of 
railway competition. 

But independent of the improvement of our great 
turnpike-roads, with the view of enabling them, as far 
as possible, to compete with railways, a very great 
necessity exists, as I have already hinted, for an exten- 
sive change in our system of parish roads. In many 
parts of England, where the most abundant facilities 
are afforded by the presence of excellent stone, to form 
the very best description of roads, we find the means 
of communication very little superior to ordinary cart 
tracks. The wealth and resources of many very fine 
agricultural districts are thus, as it were, bound up and 
prevented from being extended beyond the immediate 
neighbourhood which produces them ; while every one 
interested in the success of agricultural operations, is 
well able to estimate the influence which the condition 
of the roads exercises upon the prospects of the farmer. 
The evils of ill-formed and insuflicient roads, have 
been of late years so prominently brought into notice, 
and are now so generally admitted, that it will be 



unnecessary here to dwell on them at any length. As 
an instance, however, of the immense social improve- 
ment which has been effected in a neighbouring country, 
by means of a judicious system of inland communica- 
tion, I cannot forbear adverting to the past and present 
state of the Highlands of Scotland. Forty years ago, 
in travelling through that country, the eye of the 
observer wandered over vast tracts of uncultivated and 
apparently barren moor land, which afibrded a scanty 
subsistence to the sheep which pastured upon it. The 
heather and whin, or gorze-furze bushes, with the 
short grass peculiar to mountainous districts, composed 
the only crops of those uncultivated tracts, which of 
course were then entirely without roads or other means 
of internal communication. It forms a curious sequence 
in the chain of human events, that a boon so fraught 
with national benefit, as the establishment of good 
roads throughout the Highlands, arose out of a national 
calamity, of no less importance than the unfortunate 
rebellion of 1745. The Government, who with equal 
wisdom and liberality, had resolved on restoring to the 
country the money arising from estates at that time 
forfeited to the Crown, offered to advance one moiety 
of the sum necessary to form a perfect system of roads, 
on condition that the landed proprietors would raise 
the other moiety among themselves. This was accord- 
ingly done ; and under Mr. Telford's management, as 
engineer, the country was intersected by roads in every 
direction. The result has been, that the low grounds, 
or glens as they are called, now abound in rich pastures, 
while fields of fertile corn supply the place of the wild 
heather of the hills, and now wave to the blast which 
formerly swept unresisted over a trackless moor. The 
inhabitants of these districts, shut out as they were 
from communication with the rest of the world, were 



6 

well known to exist in a state of remarkable ignorance 
and degradation. But now their condition is widely 
different — the busy voice of human industry ascends 
from every valley — rapid strides have been made in the 
cultivation of many useful arts — and pauperism, at 
least that kind requiring the aid of charity, is almost 
unknown. 

These are a few of the signs of prosperity and 
national wealth, which at once occur to the stranger 
travelling through this country ; and if he should look 
further into its condition, he will find a population 
happy, devotional, contented with their station, and 
alike distinguished for moral principle and persevering 
industry. 

The expense of the roads thus constructed through- 
out the North of Scotland, has certainly been very 
great ; but it is no less true, that the advantages derived 
and the benefits conferred, would have amply justified, 
and been cheaply purchased by, the outlay even of 
double or treble the capital actually expended ; for, in 
addition to the immense improvement introduced into 
the agriculture of the country, the whole line of coast 
has become the seat of extensive and flourishing 
fisheries, which afibrd employment to a vast population. 
Docks and harbours have been constructed in every 
favourable situation; while communications between 
places in the interior and with the coast, are made with 
regularity and dispatch. Every facility thus given, 
has well succeeded in conferring the blessings of active 
commerce upon a country, where industry is, perhaps, 
more necessary to the enjoyment of comfort, than in 
almost any other on the face of the globe. 

Now, without meaning to infer that any part of 
England is so defective in the means of communication, 
as the Highlands of Scotland, before the improvements 



I have described, and which were effected by the High- 
land Roads' and Bridges' Commission, I would still 
suggest, that some comparison might be made between 
the two cases ; and the success which has attended the 
improvements made in Scotland, will at least furnish 
an argument for the improvement of our ordinary roads 
in England. It is no doubt an immense advantage to a 
country, to be traversed by good turnpike-roads ; but 
the value of these is much lessened, when they can only 
be reached by means of the execrable roads which at 
present lead out of them, to the various villages and 
farm-houses, not situated on the exact line of road. 

The farmer, in conveying his corn and other produce 
to market, and in sending manure to his fields, may 
comfort himself with the reflection, that whilst his 
horses are on the turnpike-road they will not be 
injured by the loads they have to draw ; but what i^ 
their situation until they reach the turnpike-road, and 
after they leave it? Of course, where the turnpike lies 
in such a direction as not to be available, the case will 
be worse than where it can be partially used. But even 
in the most favourable case, it is evident, that the 
farmer must be content with a much less load than his 
horses could draw on the turnpike-road, unless he 
attempt to carry more than a fair load on the bad roads 
to be passed over, leading into or out of the turnpike- 
road. On the other hand, if he puts on a fair load for 
the turnpike-road, his horses will be much overloaded 
when they come on the inferior kind of road ; because 
a horse, which on the former is able to draw a ton 
weight with ease, would probably on the latter be 
unable to move with more than five or six hundred 
weight. The injurious effects of this are too obvious to 
require comment ; and they establish a strong reason 
why all roads should be reduced, as nearly as possible. 



8 

to an equality in point of draught. It could hardly be 
expected, nor is it necessary, that the same breadth 
and finish should be given to all roads, which are very 
properly adopted on the main lines of turnpike; but I 
am decidedly of opinion, that all roads ought to be 
equally hard and solid ; and T would make every parish 
and every occupation or farm-road throughout this 
country, as excellent in this essential point as the 
great Holyhead road itself. For roads where no great 
traffic exists, the breadth is of little consequence; but 
on this kind of road the vehicles which do pass over 
it are usually farm waggons, containing as heavy 
weights as any on the turnpike-roads. The unfre- 
quented routes should therefore be as capable of car- 
rying heavy traffic as the great roads themselves ; and 
this they can only be when formed with a firm un- 
yielding foundation, according to one or other of the 
methods which will hereafter be described. 

I observe that, during the present session, a Bill has 
been brought into Parliament by Mr. Shaw Lefevre and 
Mr. Mildmay, " to authorize the application of a por- 
tion of the highway rates to turnpike-roads in certain 
cases." By the Act of the 5ih and 6th Will. IV. c.50, 
the performance of statute duty for the purpose of up- 
holding the roads was abolished; and the present Bill is 
intended, amongst other things, to confirm the provi- 
sions of that Act ; and with this view it is proposed to 
be enacted, " that no person is liable to perform any 
statute labour upon any turnpike-road in England, or 
to pay any composition in money in lieu thereof." 

The old method of supporting the turnpike-roads being 
thus abolished, the Bill proceeds to enact, that justices 
of peace may inquire at special sessions for highways 
into the revenues and condition of the repairs of turn- 
pike-roads, and if necessary may apportion a part of 



9 

the highway rate to the trustees of the turnpike-road ; 
and the money so received is to be wholly laid out in 
the actual repair of such part of such turnpike-road as 
lies within the parish from which it was received. 

It seems likely, that the condition of the turnpike- 
roads will be much benefited by the provisions of this 
Bill, should it receive the sanction of Parliament. Many 
of the trusts on these roads are now so seriously im- 
poverished, that the sums they may thus claim from the 
highway rates will be of ijreat service, and the farmers 
will also be relieved from what in some cases may be 
considered an oppressive burden ; but whether the 
levying- of highway rates to the extent which will be 
rendered necessary by this Act, will not press with 
undue severity in other quarters, is a question I am 
unable to answer. It w ould also be matter of great 
complaint, if the ordinary highways, not being turn- 
pikes, should become worse off than at present. It 
would require very little argument to prove that these 
roads stand very much in need of improvement; and 
should the surveyors be rendered less able to support 
them than at present, Ave may soon expect to see them 
almost impassable. 

I have already alluded to the necessity for some ex- 
tensive improvement in our system of common roads ; 
and as this improvement would be principally effected 
by means of manual labour, it might be made at a very 
small outlay of capital, and would afford employment 
to the vast numbers of paupers who now crowd the 
workhouses of this country. It is true, that attempts 
have already been made in some places to improve the 
roads by employing the paupers upon them ; but I con- 
tend that their labour has not hitherto been properly 
applied, and in fact until they are made to work upon 
a regular system, and under proper management, it will 



10 

be unreasonable to expect any remarkable result from 
their labours. An excellent opportunity is now afforded 
to the guardians of the poor throughout the country, to 
assign the surveyor of highways a certain number of 
the most able bodied paupers, to be employed in the 
improvement of the common roads; and if the labourers 
so employed were paid a trifling sum in addition to the 
workhouse allowance, they would soon become useful 
in performing the task assigned to them. In my opinion, 
it is almost impossible to conceive the extent of benefit 
which will arise from the employment of labour in the 
manner I have suggested : but it is necessary to observe, 
that the surveyors should be made to act on a fixed 
system, because the country has already sufficiently 
suffered from the ignorance and incapacity by which 
too many of this class are distinguished. Written in- 
structions in the form of specifications should be drawn 
out by competent engineers, practically experienced in 
the construction and management of roads ; and to these 
instructions, which should be adapted to particular dis- 
tricts of country, the surveyors should be bound strictly 
to adhere. A general knowledge of the principles of 
roadmaking would thus be diflused, and at no distant 
period, we might expect to reap the advantages of this 
system. A scale of prices should be established for 
the payment of the labourers by measurement of the 
work performed, and not, as they are usually paid, by 
day work. This latter custom is extremely bad, be- 
cause its certain consequence is to reduce all the 
workmen to one uniform state of indolence and ineffi- 
ciency. To the minds of men so employed, no advan- 
tage presents itself from the exertion of any thing like 
superior industry. Since all the labourers are paid 
alike, it is evident that the best workmen, or those 
who under other circumstances would become good 



11 

workmen, have no possible inducement to exert them- 
selves more than the idlest and weakest of the whole 
gang. Hence the power and energies of these men are 
paralyzed to an extraordinary extent ; and it is frightful 
to reflect on the serious and accumulated evils arising 
from the very injudicious way in which they are em- 
ployed by the overseers. To the operation of this system 
alone, the overseers are indebted for repeated failures 
in their attempts to employ the poor with advantage. 
If, however, these very same men were employed at a 
fair remunerating price in proportion to the work they 
perform, there exists no reason on earth why they 
should fail to obtain an honest subsistence for their 
families ; and at the same time, the parishes and the 
country will derive a real and solid advantage from the 
outlay of capital in the shape of poor rates. The ad- 
vantage to be derived from the change of system I 
have recommended, is simply this, that the money 
expended in relieving able-bodied paupers, instead of 
producing very little or no profitable result, may be 
applied in the most useful manner, as part payment 
for the work done by paupers, in the improvement of 
the roads. 

In the succeeding chapters I shall endeavour to 
point out a systematic mode of improving the roads, 
in which the principal ingredient will consist of actual 
labour. If I could show no other means of introducing 
effectual improvements than the application of expen- 
sive materials, and the consequent outlay of consider- 
able funds, I should consider it useless to devote 
attention to the subject; but with the different opinions 
I have ventured to express, and with different objects 
in view than to recommend extravagant expenditure, I 
proceed to the practical details of the subject. 



\\ bie*^^^'" 



100}^ 




/,. : ii 


IV - 1-. 



C/c// 



12 



}l ',: 



CHAPTER II. 

On the Method of improving an existing Road. — The 
Figure or Profile which shoidd be given to the Bed 
and Surface. — Forming the Foot-pcdli and Fences. 

As a first step to improve the condition of an old 
road, the direction and general levels of which cannot 
be altered, I should proceed to cat down high fences, 
if these exist, on each side of the road, and regularly 
to trim the hedges, so that the height of the bank and 
fence should not exceed four or five feet above the 
level of the road. The soft mud should then be scraped 
from the surface, and the bed of the road formed with 
a regular convexity of one inch in five feet, which will 
give in a road of thirty feet wide, a rise of nine inches 
in the centre. In advancing the opinion, that the bed 
of the road should be formed with a curved surface, 
I am at variance with the doctrine of many road- 
makers, who contend that the road material should be 
laid on a flat surface. The principal reason which has 
induced me to adopt the practice of curving the bed is, 
that the drainage is hereby rendered more easy and 
effectual, and the curved figure of the road on the 
upper surface is preserved, by laying on the road 
covering of equal depth entirely across the road. Here 
again a very common opinion is, that the depth of 
material in the centre of the road sliould be greater 
than at the sides ; but for my part, I have never been 
able to discover why the sides of the road sliould be at 
all inferior to the middle in hardness and solidity. On 



13 

the contrary, it would be a great improvement in 
general travelling, if carriages could be made to adhere 
more strictly to the rule of keeping the proper side of 
the road; and the reasonable inducement to this prac- 
tice is obviously to make the sides equally hard and 
solid with the centre. In many roads, even where con- "Sr 

siderable traffic exists, the only good part of the road / 

consists of about eight or ten feet in the centre, the ' ; 

sides being formed with small gravel quite unfit to 
carry heavy traffic ; and the consequence is, that the 
whole crowd of vehicles is forced into the centre track 
of the road, thus at least doubling or trebling the wear •-' 

and tear which would take place if the sides were as 
they ought to be, equally good with the centre. Another 
mischievous consequence is, that when it becomes 
necessary to repair the centre of the road, the carriages 
are driven off the only good part on to the sides, which ^ 

consist of weak material, and are often even dangerous 
for the passage of heavily laden stage coaches. On 
the other hand, if equal labour and materials be ex- r 

pended on the whole breadth of the road, it is evident i 

that the wear and tear will be far more uniform ; and 
when any one part requires repair, the traffic may with 
safety be turned on to another part. Hence I should , 
always lay on the same depth of material all over the 1 _^ 

road ; and this alone will of course render it necessary 
to curve the bed of the road. With respect to the 
kind of curve to be formed, I think the segment of a 
large circle, in which the chord of thirty feet shall have 
a rise or versed sine of about nine inches, will form 
just as good a road as the segment of an ellipsis adopted 
by some engineers. The circle, with the circumference 
of which I would recommend that both the bed of the 
road and its upper surface should coincide, would be 
formed with a radius of 150 feet ; and as a guide for 



\' 



14 

the workman in making the proper section, it would be 
very useful to place in his hands a jjiece of board, 
having one of its edges curved to the proper figure, and 
this edge being applied to the road surface, will at 
once determine the coiTCct degree of curvature. 

In many roads, where the thoroughfare is not very 
extensive, a footpath and verge may be thought an un- 
necessary addition to the expenses ; and certainly, in 
improving the ordinary farm and occupation roads, it 
is natural to suppose that labour and capital would be 
expended to the greatest advantage in forming a hard 
and solid track for waggons and carts. In the case of 
these roads, the breadth of roadway is of course not 
very important. It is hardly possible to form any 
adequate idea of the beneficial effects which would 
arise from the construction of even ten feet in width, 
of hard solid road, in place of a broken uneven sur- 
face, deeply furrowed by the frightful ruts invariabl}^ 
found in these roads. 

In forming the bed of a road, before constructing 
the foundation, whether this is to consist of pitched 
stones or of concrete, as hereafter described, it should 
be borne in mind, that if the substratum be tolerably 
firm, the natural surface of the ground should be dis- 
turbed as little as possible. The practice of forming 
the bed of a road below the natural surface is decidedly 
bad, wherever it can be avoided. It adds consider- 
ably to the difficulty of drainage, and the only good 
which it can efi'ect — namely, to form defined boundaries 
or edges for the carriage road-way on each side, — can 
be equally well done by a little earth or mould, and a 
turf placed on edge alongside the footpath and verge. 
If the road is to be metalled over a tract covered with 
green sward, this should be allowed to remain, and the 
pitching or concrete laid immediately upon it, with the 



15 

exception merely, that the ground should be rounded 
off to the necessary convexity, the middle part or centre 
of the road track remaining undisturbed. Another me- 
thod of forming the convexity in the bed of a road, 
which may often be followed with advantage, is to lay 
on the natural surface a sufficient quantity of the earth 
taken from the ditches, to form the required figure, and 
if this earth be well pounded, the concrete or pitching 
stones may safely be placed upon it. This, however, 
must never be attempted unless the material be hard 
and porous, such as sand, gravel, or rubbly rock, for 
any description of clay or mud would form a very 
unsound bottom. 

The following chapters will describe so fully the 
method of pitching the road with stones placed on 
edge, and the method of forming a concrete foundation 
for the road material, that it will be unnecessary in this 
place to enter upon that part of the subject. It may 
not however be foreign to the business of this chapter, 
to make some remarks on the upper covering of the 
road above the pitching or concrete. In laying on this 
upper covering, many surveyors commit a great error 
in not making a distinct difference between angular or 
broken stones, and those rounded smooth pebbles of 
which gravel is usually composed. The former cannot 
be too well cleaned before being laid on the road, 
because even when entirely divested of all earthy 
matter, they soon become wedged and bound closely 
together, when the pressure of carriages comes upon 
them. But the case is different with the smooth round 
surfaces of gravel ; for if this material be entirely 
cleaned by means of washing and repeated siftings, 
the pebbles will never bind, until in a great measure 
they become ground and worn down by the constant 
pressure and rubbing against each other. Before this 



IG 

takes place, the surface of the road must be considerably 
weakened, and will in fact be incapable of supporting 
the pressure of heavy wheels, which consequently sink 
into it, and meet with considerable resistance to their 
progress. Under these circumstances, it seems that 
the practice of too scrupulously cleaning the rounded 
pebbles of gravel, must be decidedly condemned; and 
the question then arises, to what extent should the 
cleaning process be dispensed with ; or, in other words, 
what proportion of the binding material found in the 
rough gravel, as taken out of the pit, should be allowed 
to remain in the mass intended to be placed on the 
road ? In answer to this inquiry I should infer, from 
the nature of the binding required, in order to form a 
proper surface for the road, that the least quantity of 
earthy material which ought to remain amongst the 
smooth pebbles, is precisely that quantity which would 
fill up the interstices of a portion of the clean gravel, 
without adding to its cubical contents. The propor- 
tion necessary for this purpose, may be determined by 
the following experiment: Take any given mass, say 
one cube yard, of perfectly clean washed gravel, 
entirely divested of every particle of adhering matter, 
and place it in a box or trough, containing the same 
cubical contents ; then pour in water till it rises to the 
surface, when it is evident that the cubical capacity of 
the water so employed, will represent exactly that 
quantity of matter which will fill up all the vacuities 
between the pebbles, and retain them firmly in their 
places, under the pressure of any weight passing over 
them. Hence the reason for supposing that this should 
be the minimum quantity of binding material, to be left 
in the gravel before placing it on the road. In actual 
practice it may be found unnecessary to resort to this 
experiment ; and even where it can be made, it will 



17 

hardly be possible to decide on the exact kind of sieves 
through which the gravel should be passed, and the 
other processes to which it should be subjected, in 
order that neither more nor less than the precise pro- 
portion of earthy matter should remain in the prepared 
gravel. The experienced surveyor, however, would be 
able after a little examination to judge of the extent to 
which the gravel should be cleaned. A long course of 
experience, accompanied by attentive observations on 
these details in the practice of roadmaking, has con- 
vinced me, that it is much better and safer, as a general 
rule, to leave too much of the binding material in the 
gravel, than to divest it too completely of this sub- 
stance. When the gravel is placed on a road without 
being sufficiently cleaned, the constant wear and tear, 
aided by the occurrence of wet weather, causes the 
harder material or actual gravel to be pressed close to- 
gether; and the surplus of soft binding material remain- 
ing after the interstices between the pebbles are filled 
up, being then forced to the top, and usually mixed with 
water, becomes mud, and according to the usual practice 
should be scraped to the sides of the road. When this 
has been done the surface is usually firm and solid ; 
because the hard gravel below the mud has become 
perfectly bound, without at the same time being broken 
or ground to pieces. Suppose next a road covered 
with gravel too much cleaned, where it is evident that 
the destruction of the gravel will continue until it 
becomes broken into angular pieces, and a sufficient 
quantity of pulverized material has been formed 
to hold the stones in their places and thus to effect 
the binding of the mass. I need hardly say, that the 
deterioration thus occasioned to the road is an evil 
of much more importance, and one much more to be 
avoided, than that occasioned by employing stones not 

c 



18 

sufficiently cleaned. Regardless of all this, however, 
it is the practice of many road surveyors, to insist that 
all gravel of whatever quality shall be rendered per- 
fectly clean by repeated siftings, and even by washing, 
until at last it becomes entirely divested of all that 
may properly be considered the binding part of the 
material. 

The qualities of gravel are so exceedingly various, 
that it is impossible to lay down any general rule as to 
the preparation it should undergo before being used on 
the road. The principal varieties consist of quartz or 
silex, and are usually the detritus of the older rocks. 
Considerable beds of gravel are how^ever formed of the 
flints which have been washed from the upper chalk 
strata ; and in the west of England, the detritus of the 
oolitic rocks forms extensive deposits of gravel. Those 
varieties usually require the least cleaning which are 
mixed with sharp angular particles of sand, sometimes 
impregnated with iron ; and in fact, a great deal of 
this kind of gravel may be used on the roads after being 
once sifted, as it seldom requires any washing. Some 
of the flint gravel requires little preparation, except that 
of breaking the larger lumps to a suitable size, which 
should not much exceed that of a large hen's e^^ : but 
this is not always the case ; for I have met with this 
kind of gravel in a very dirty state, much mixed with 
chalk and clay, and requiring a good deal of prepara- 
tion before it could be used. This kind of gravel is 
often found deposited in extensive tracts of low flat 
land ; but the cleanest kind of flint gravel is generally 
found in dry moor land, elevated above the natural 
drainage of the country. The following extract, from 
one of the specifications for an improvement on the 
Holyhead road, contains Mr. Telford's directions on the 
preparation of gravel for Ihc road covering : — 



19 

*' The eighteen feet middle of this road is to be 
covered with the best gravel or pebbles the country 
aftbrds; it must be washed and broken, so that no stone 
shall remain or be put on the road that will exceed two 
inches and a half, or be less than one inch in diameter. 
All the gravel intended for the eighteen feet middle of 
the road to be riddled through three-quarter-inch sieves; 
all that passes through to be kept for the sides. The 
sides of the road to be of gravel, but it need not be so 
large as that used for the centre. It must be washed 
and riddled on sieves of one quarter inch meshes ; the 
screenings to be kept for the footpath. The whole 
surface to be covered with one inch and a half of good 
binding gravel." 

The following is from a specification by the same 
eminent engineer, in a case where the road improve- 
ment was made through the street of a town (Fenny- 
Stratford): — 

*'The whole width of pavement is to be covered with 
broken limestone two inches thick ; the middle eighteen 
feet of this is then to be covered with four inches in thick- 
ness of theHartshill stone, broken so that no piece shall 
exceed two inches and a half in the longest diagonal 
line, or be less than will pass through a sieve of three- 
quarter inch meshes, on which it must be riddled to free 
it from dirt before it is applied to the road. The sides 
are to be made up of good gravel, washed, sorted, and 
broken if necessary. No stone is to be left on the road 
greater than will pass through a ring of two inches 
diameter, and all round ones are to be broken. The 
largest assortment of gravel is to be put next the 
Hartshill stone, and the smaller sort next the sides of 
the road. No gravel is to be put on any part of the 
road that will pass through meshes of half inch square. 
These gravel sides are to be four inches thick at the 

C 2 



20 

junction with the Ilartshill stone, and two inches at 
the sides." 

Footpath. — Simple as the task appears to be, it 
is certain that many very miserable failures have taken 
place in the attempt to form a good footpath. This 
will generally happen when the material employed for 
the purpose is of a clayey nature, and capable of hold- 
ing water. The earth taken out of the ditches, for 
example, is usually very unfit to be placed in the foot- 
paths, and should therefore be reserved to form the 
lower part of the mounds or banks for the quicksets. 
The best method of constructing a good footpath, is to 
raise it by layers of about three inches in thickness, 
composed of the scrapings of the road usually called 
road-drift. Silty sand, or small gravel of a binding 
nature, or the siftings of coarser gravel, will also form 
excellent footpaths. Each layer should be well 
pounded with a wooden rammer or pounder, about five 
inches in diameter, until made firm and solid, when 
another layer may be laid on and the process of pound- 
ing repeated. About four layers will bring the footpath 
to its proper level ; and the surface, which should have 
the slight convexity of one inch in three feet, should 
then be smoothly raked over, and if possible should 
be allowed to consolidate and harden before cattle, 
wheelbarrows, &c. are allowed to travel upon it. 

Where it may be inconvenient to obtain a sufficient 
quantity of road-drift, or such other material as I have 
described for the footpaths, it will be a very good prac- 
tice to form the lower part with rubble stones, with 
coarse gravel, or any other porous material, on which 
may be laid a single three-inch layer of road-drift to 
form the top of the path. Before concluding these re- 
marks on the construction of footpaths, I cannot forbear 
adverting to a system pursued by many road surveyors, 



21 

of placing coarse gravel and large stones in the upper 
part of the path. Every one at all accustomed to walk 
on a footpath so formed, must be aware of the very un- 
pleasant consequences to the feet ; and we may readily 
conceive the misery occasioned to pedestrians, who are 
compelled to make long marches on this kind of path. 
The obvious rule to be followed is, that the upper part 
of the path should always be composed of the fine 
gravel or road-drift already spoken of, so that the sur- 
face of the path may be smooth and uniform as well as 
hard and solid, — the former of these qualities being not 
a bit less necessary in a good footpath than the latter. 

Fencing. — In all districts of country where the 
fields are inclosed, it is usual and necessary to construct 
a fence on each side of the road to define its boundary 
and prevent trespass. Walls built of dry rubble stone 
are a very common kind of fence, in places where suit- 
able stone abounds; and with respect to these very little 
need be said — their construction is so simple and gene- 
rally so well understood by the country wallers, as they 
are called, that we may pass at once to the common 
quickset hedge more generally erected as a fence. 

Different opinions are entertained as to the number 
of plants which should be placed in a given length, in 
order to form the best kind of hedge. It seems how- 
ever to be generally admitted, that the quicks should 
be planted either when the sap is descending into the 
grounder ascending into the plant; that is, either in the 
autumn or spring of the year. Upon the whole, I think 
myself the autumn is the most suitable time, and if the 
weather be open the planting may continue through the 
winter. I think generally that nine good strong healthy 
plants in each lineal yard, that is, a single row of 
quicks placed four inches apart, will form an exellent 
hedge ; although in some cases two rows arc planted. 



containing together eighteen plants in each yard. The 
plants should be of not less than three years' growth, 
which will allow them to have been two years in the 
nursery-ground after being transplanted from the seed- 
lings-bed. The mould should be of the bes,t quality, 
and should be placed in the bank to the depth of at 
least two feet, in order that the roots of the quicksets 
may have sufiicient room to strike. The kind of soil 
most suitable for quicksets is that of a light sandy or 
gravelly nature ; and if it could be slightly mixed with 
peat would be much improved. A stiff clayey soil is 
decidedly bad ; because in summer it becomes hard and 
dry, and in this state the smaller fibres which feed the 
plant cannot penetrate into it, and the quicks conse- 
quently die for want of sustenance. In winter the 
frost will penetrate very much into clayey soil, and not 
only are the plants destroyed by its expansion and con- 
traction, but also by the excessive coldness of this kind 
of earth. Again, if the soil be very light and porous the 
bed becomes too dry in summer to afford nourishment to 
the plants ; but I never knew^ a quickset hedge planted 
in a sandy or light gravelly soil injured through the 
winter. Hence the only precaution necessary in such 
a soil is, to prevent the destructive eflects of the dry 
summer weather; and this I am convinced would be 
most efl'ectually done if the earth could have a portion 
of light slimy peat mixed with it. T may mention, that 
the most healthy and luxuriant quickset hedges I have 
ever witnessed, are planted in a mould of this de- 
scription. The quicksets, if properly planted and well 
cleaned and weeded twice a year, ought to grow up 
into a tolerable hedge in about three years ; although 
to prevent it from being broken through too soon, it 
juay be advisable to allow the post and ruil-lence to 
remain as an additional protection for five or six years ; 



23 

until in fact the timber becomes worn out and de- 
stroyed, which it usually is by that time- 
Some hedges, however, require a much longer time 
to acquire anything like the strength of a fence ; but 
in such cases the failure is usually attributable to im- 
proper management and unsuitable soil. A long tough 
description of couch grass, with strong roots, is very 
apt to grow up with the young shoots; and unless this 
enemy be carefully destroyed, at least twice a year, it 
is in vain to expect the quicks to acquire a healthy 
growth. But probably the most extensive kind of 
destruction is that occasioned by the calves and sheep 
passing along the road, or pasturing in the adjoining 
fields. These animals, and particularly the sheep, are 
remarkably fond of the green juicy heads of the young 
shoots, which they bite off whenever they can reach 
them ; and this practice alone, if allowed to continue,, 
will always prevent the quicksets exposed to it from 
attaining their proper size and strength. The method 
of guarding against this source of injury, is obviously 
to place the post and rail-fence at such a distance 
from the quicksets, as to make the latter beyond the 
reach of the sheep and calves which are in the habit 
of thrusting their heads through the openings between 
the rails, in order to obtain this very favourite kind of 
food. For want of attention to this precaution, many 
hedges, which would probably have formed very fine 
fences, have to this day produced nothing but stunted 
imperfect shoots, thus of course entirely failing to realize 
all expectations of ever growing up. In many road speci- 
fications the directions to the contractor have been, to 
place the post and rail-fence so near to the quicksets, 
that they must infallibly be destroyed from the cause I 
have mentioned ; and the result has been, in almost all 
such cases, that the attempt to procure a good fence 
has entirely lailed. 



24 



CHAPTER III. 

On the Improvement of Roads by means of pitching the 
Bottom with Stones placed on Edge, as adopted by^ 
Mr. Telford on the London and Holyhead Road. 

In those districts where granite or the older strati- 
fied rocks prevail, the roadmaker possesses the advan- 
tage of having at command the very best possible 
materials for constructing a perfectly hard and solid 
road. So highly has granite been prized as a covering 
for roads in the neighbourhood of the metropolis, on 
which of course immense traffic exists, that this mate- 
rial has been procured from the island of Guernsey, 
from Dartmoor forest in Devonshire, and other places, 
at an expense of not less that a guinea per ton. Of all 
the granites ever used as a road-covering, the Guernsey 
is esteemed the best; and from a series of experiments 
made under the direction of Mr. Walker, President of 
the Institution of Civil Engineers, it appears, that the 
wear of different kinds of granite is in the following 
order: Guernsey, Herm, Peterhead (blue), Heytor, 
Aberdeen (red), Dartmoor, Aberdeen (blue.) 

The grand distinction between the granite and lime- 
stone rocks, even of the hardest class, is, that the former 
are far more capable than the latter of resisting disin- 
tegration by the action of water and frost; and as 
they possess in an eminent degree the qualities of hard- 
ness and durability, they may safely be used, either in 
the shape of blocks to form the foundation of the road, 
or, whcii broken to a suitable size, may be applied as a 



25 

top covering with which the wheels are to be in imme- 
diate contact. If the bed of a road, after being made 
perfectly dry, be covered over with a layer of broken 
granite, the angular shape of the stones will allow them 
to wedge and dovetail as it were into each other, so 
that w hen pressed by the wheels rolling over them, the 
whole will form a solid resisting mass of great stabi- 
lity and hardness. Hence, although I would recom- 
mend that a regular foundation made in the manner 
hereafter described, be laid down in all roads where 
anything like extensive traffic is to be carried on, yet if 
it were asked in what case this foundation might with 
the least injury be dispensed with, I should answer, in 
that situation where the road metal consists of broken 
granite. In no other case than this, however, should the 
general rule on any account be departed from, of con- 
structing a solid artificial foundation before laying on 
the top covering. Even on the score of economy, the 
road pitching should be adopted in preference to the 
broken stone metalling, because it will be found cheaper 
to pitch the road with hard stones than to break them 
up for a road covering. 

Two distinct kinds of road foundation will be de- 
scribed in the following chapters, namely — first, the 
pitched bottom foundation mentioned above, which was 
introduced by Mr. Telford, and which consists of a 
close firm pavement of stones, placed side by side on 
their broadest base ; and next, the concrete foundation, 
composed of gravel or broken stone, mixed iri proper 
proportions with lime or cement. The former of these 
two kinds will be applicable to those districts where, in 
place of granite and whin, the stratified rocks of lime- 
stone and sandstone prevail — to every situation, in 
fact, where any description of stone can be procured 
at a reasonable price. 



26 

Although some kinds of sandstone are tolerably 
hard, the prevailing characteristic is that of a dry 
brittle rock, easily broken and easily ground to powder, 
therefore generally very unfit for the purpose of a road 
covering. All kinds of limestone are still more inappli- 
cable as a top coating than sandstone. It has often 
been observed, that in dry weather limestone forms an 
excellent road; but owing to the capacity of this mate- 
rial for water, the slightest rain produces an almost 
instantaneous effect on this kind of road. A surface, 
which in dry weather is, perhaps, perfectly hard and 
smooth, becomes after a shower of rain a complete 
puddle: the water renders the stone quite soft, and in 
this state it is soon ground into mud. Where there is 
much traffic, a very short continuance of Avet weather 
will complete the destruction of a coating six or eight 
inches in thickness, which under these circumstances 
will be cut through by the wheels in a marvellously 
short space of time. If the mud be not immediately 
scraped away, it becomes very clammy in the process 
of drying, and in this state the road naturally requires a 
very heavy power of draught. In dry weather the mud 
formed during wet seasons becomes dust; and in roads 
of this kind it usually exists to an extent seriously an- 
noying to the unfortunate travellers, who sometimes 
can hardly escape being smothered. 

Should a frost occur the limestone road will suffer 
much more than from the rain — the moisture which this 
kind of stone so copiously imbibes, will be expanded 
by the action of the frost to a larger bulk than when in 
the liquid form ; and the consequence of this is an im- 
niediate shattering and bursting of the stone, which in 
many cases is almost reduced to powder, or at any 
rate is rendered capable of being crushed by the first 
wheel wiiich may pass over it. As soon as the sun 



27 

begins to melt the frost, the limestone covering becomes 
ten times more adhesive than ever : it may now with 
truth be compared to birdlime, so tenaciously it adheres 
to the wheels of the carriages. The work of destruc- 
tion becomes rapid and astonishing in its effects ; the 
whole road is torn to pieces, immense patches of the 
covering are entirely stripped from the surface, and the 
road deeply indented with large hollows. Such are the 
effects produced even on the best kind of limestone 
road by a few nights of slight frost, succeeded by the 
fine sunny mornings of autumn and some of the mild 
winters. Upon the whole, the objections to limestone 
are so numerous and so well founded, that this material 
should never in any situation be used as an upper 
covering, or road metalling. 

In condemning the use of broken lime and sandstone 
as an upper covering, I would however except the hard 
varieties of the latter which contain iron. Sandstone 
of this kind, found in the green sand ranges of Surrey 
and Sussex, is extensively applied on the neighbouring 
roads, where the surface formed by this kind of stone is 
extremely hard, and indicates a very small amount of 
friction. On a part of the Surrey and Sussex road, in 
the neighbourhood of Red Hill, I have been forcibly 
struck with the excellent surface formed by this kind 
of stone. Although not in possession of any actual 
experiment on the amount of friction, yet from having 
passed over it a great number of times, and from ob- 
serving the ease and speed with which horses drawing 
carriages, coaches, and gigs, are able to ascend hills of 
considerable acclivity on which this stone has been laid 
down, I should venture to predict, that the friction is 
not more than on the best granite road I ever saw. The 
same kind of iron sandstone is found at Pulborough, 
and other parts of the sand range underlying the South 



28 

Down chalk hills ; and there also it has been exten- 
sively used as a road material, particularly between 
Pulborough and Billinghurst, a part of the road acknow- 
ledged, by the coachmen and others acquainted with it^ 
to be the best between London and Arundel. 

Whilst, however, no doubt can be entertained of the 
general unfitness of limestone and the softer kinds of 
sandstone for the upper covering of a road, we are in- 
debted to the late Mr. Telford for the knowledge of a 
most admirable application of these kinds of stone to 
the purposes of roadmaking. Proceeding on the prin- 
ciple, that next to the efficient and thorough drainage 
of a road, the securing a good, hard, firm foundation is 
the most important object to be attended to, that 
eminent engineer directs, in his specifications for works 
on the London and Holyhead road, that "upon the 
new surface or level space prepared for the road mate- 
rial, a foundation of limestone, sand, or marlstone is to 
be laid in the form of a close firm pavement. The 
depth of each stone is to be seven inches in the middle 
of the road, and five inches at the sides ; the stones are 
to be set lengthwise across the road, they are to be 
laid on their broadest edge, and the breadth of the upper 
edge is in no case to exceed four inches; all the in- 
equalities in the upper part of the pavement are to be 
broken off with the hammer, and all the interstices filled 
with stone chips, firmly wedged or packed by hand and 
a light hammer, so as to form a regular convexity of 
one inch in nine feet from the centre, and three inches 
at the channels, or at the distance of fifteen feet from 
the centre." 

The kind of pitching here described consisted of 
sand and limestone, which would have been quite inap- 
plicable as a top coating for the road; but which was 
found, when covered by a layer of gravel or hard broken 



29 

stone, to form a most excellent road. It is true, that 
when this method of road pitching was first adopted, 
the opinions of several scientific engineers were op- 
posed to it ; but the superiority it possesses over the 
ordinary mode of laying on the gravel or broken stone 
in a body, has now become so evident, that few persons 
are any longer disposed to doubt the merit of its intro- 
duction into the practice of roadmaking. 

Surveyors, therefore, in those districts which do not 
produce the harder kinds of rock, have, in the way de- 
scribed, an opportunity of employing to great advan- 
tage the inferior descriptions of stone, which are very 
commonly found all over England. The adoption of 
this method is recommended by numerous considera- 
tions, more especially to all those parishes which are 
burdened by a large number of paupers. The stone to 
be used for the pitching, after being quarried, requires 
very little breaking; because sandstone, and the upper 
or less valuable beds of limestone, are generally quarried 
as waste or spare rubble, in pieces of about the proper 
size for road pitching; and most quarries produce more 
of this stuff than can be worked up in any building. 
The price of this kind of stone at some quarries is three- 
pence a cart-load ; and I never knew more than six- 
pence charged. In some places, however, where the 
quarry has to be newly opened, it may cost a shilling 
per cube yard; but if the quarry be situated on a 
common or waste piece of land, the stone costs the 
parish nothing but the labour of the workmen. 

The principal expense then, besides that of carting 
from the quarry to the road, is the labour of pitching the 
stones by hand ; and the art of performing this kind of 
work with neatness and expedition is very soon learned 
by a labourer of ordinary capacity. The price usually 



30 

paid for the actual labour of laying down the pitching 
on the Holyhead road, is from one shilling to fourteen 
pence per lineal yard of 30 feet wide ; and a workman 
of tolerable industry can with ease lay down about four 
yards in length per day. 

The practice of forming a pitched foundation, as 
described in the preceding extract from one of Mr. Tel- 
ford's specifications, having been employed with great 
success in most of the improvements executed on the 
Holyhead road, has thus received the valuable sanc- 
tion of practical experience ; and may safely be recom- 
mended as an effectual cure for those troublesome cases 
in roadmaking, where the stratum composing the bed 
of the road displays a tendency to burst through and 
mix with the road materials. It is vain to argue, that a 
great body of gravel or broken stone will of itself 
prove sufficient to prevent the sub-soil from rising. 
To those who adopt an idea so erroneous, I would 
simply observe, that they can never have been ac- 
quainted with any very difficult cases of this kind. I 
have myself, in breaking up old roads, found layer upon 
layer of excellent gravel to the depth sometimes of not 
less than four feet, but completely mixed with the 
clayey material which had found its way from beneath. 
Where a road happened to be carried over this kind of 
material, and it was found to mix with the gravel which 
formed the covering of the road, the old system, for the 
most part, recognized no other practice of stopping the 
evil than that of loading the road with a further quan- 
tity of gravel or broken stone — an application whicli 
proved of an extremely temporizing and imperfect 
character; because no sooner had one layer of gravel 
become mixed with the sub-soil, than the latter rose 
into the coating last put on, and tlic whole mass of road 



31 

tiiaterial became reduced to the same clogged and spongy 
condition as before the application of the new gravel. 
In all obstinate cases of this kind, however, the pitched 
foundation will most effectually prevent any rising of 
the sub-soil, and the gravel laid on as an upper coating 
will then have a fair chance of binding and becoming 
sufficiently hard and solid to form a good travelling 
surface. 

In the following chapter will be found some account 
of the method resorted to for the improvement of the 
Highgate Archway Road, after it was placed under the 
management of Mr. Telford. I had in that case actual 
and ocular demonstration, that the various processes 
of laying brushwood and tin chippings in the bed of the 
road had previously been adopted ; and in many other 
cases, I have seen the remains of fagots which had 
been interposed between the upper coating of gravel 
and the sub-soil, which it was vainly anticipated would 
in this way be prevented from rising. It would seem 
that those old roadmakers, who have so tortured their 
inventive faculties to devise means for securing a firm 
foundation for the upper coating of the road, would 
hardly agree to some of the axioms laid down by a 
modern road surveyor of eminence, whose name, with 
an appropriate termination, has been introduced into 
the English language to distinguish the system of road- 
making of which he is the author. According to this 
gentleman, " it is no matter whether the sub-stratum of 
a road be hard or soft." The advocate of a doctrine so 
heterodox might derive an useful lesson from the expe- 
rience of those old roadmakers, who were evidently at 
so much pains to correct and obviate the misfortune of 
a soft sub-stratum. I can scarcely help thinking, that 
such a doctrine could only have originated from a very 



32 

superficial acquaintance even with the existing con- 
dition of roads. To most persons in the habit of prac- 
tising anything like observation as they pass through 
life, there are few differences more striking than that 
between a road formed on a soft foundation, and one 
which has the advantage to pass over a hard sub- 
stratum. 

The great principle of utility is strikingly consulted 
in Mr. Telford's practice of pitching the foundation of 
the road; for it must be borne in mind, that the mate- 
rials to be used for this purpose would for the most 
part be utterly useless for a top covering, and yet when 
employed as a pitching in the way before described, an 
extremely durable and excellent road is the result. If 
road surveyors could only be prevailed on to adopt the 
system of pitching their roads with such materials as 
are found pretty generally throughout this country, I 
am certain they would soon find, in the superior charac- 
ter of the roads they would be enabled to form, ample 
cause to congratulate themselves on having stepped 
aside from the old practice of loading the road with 
enormous quantities of gravel or broken stone. 

In considering the quality of stone proper for the 
purposes of road pitching, it is an error to suppose that 
none but very hard stone should be used. The soft 
kinds of sandstone and freestone, and very inferior kinds 
of limestone, have been extensively used on the Holy- 
head road ; and I am persuaded that blocks of chalk, 
particularly of the kind called rock-chalk, would form 
a very excellent material for pitching. In any case, 
however, where chalk or even limestone is used for 
pitching, the drainage of the road becomes of more than 
ordinary importance. In order to preserve this mate- 
rial, it is absolutely necessary to protect it from the 



33 

atmosphere, whence it would otherwise imbibe moisture 
which would shortly produce very destructive eflects ; 
and the precaution of protecting the pitching from the 
air will evidently be entirely useless, unless the bed of 
the road be first made perfectly dry ; but if this duty be 
eftectually attended to, chalk itself, and the softer kinds 
of limestone rock, will resist the progress of decay for 
a very long time. 



34 



CHAPTER IV. 

On the Improvement of the Highgatc Archivay Roady 
by means of a Concrete Foundation, composed of 
Gravel and Cement. 

The first effectual method adopted for the improve- 
ment of this road, was executed under Mr. Telford's 
directions in the year 1828 ; and for some time the 
new kind of foundation then introduced, consisted of 
moulded bricks formed of gravel and Parker's cement. 
The process of making and laying these concrete bricks 
was however found to be very expensive, and many 
practical difficulties attended their use. It was impos- 
sible to prevent them from breaking and falling to pieces 
when taken out of the moulds, and from crumbling and 
breaking when placed in the heaps to undergo the pro- 
cess of drying; whilst many others, which had up to 
that time remained whole, were broken to pieces in the 
act of removal by carts, although this operation was 
performed with the utmost care, and straw placed be- 
tween each course to prevent breakage. In this way I 
am quite safe in asserting, that at least one-third of the 
whole quantity of moulded bricks were lost. In conse- 
quence of these numerous objections, the practice of 
using the bricks was at ray suggestion eventually 
abandoned, Mr. Telford directing that the concrete 
should be laid in mass without being moulded into tlie 
form of bricks ; and from this period the mixture w as 
made up in a wooden trough on the ground, and then 
carefully placed in the bed of the road ; and before it 



35 

was allowed to get hard, a wooden mould shaped thuSj 
like the letter V, was stamped transversely at the dis- 
tance of every foot apart, in order to allow any water 
to drain down this indented channel into the side drain, 
and also, that the covering of stone or gravel might more 
easily bind and become solid on the concrete. This 
method, although a great improvement on the first plan, 
was very expensive and tedious, principally on account 
of that property in the cement by reason of which it 
sets and becomes hard, in a remarkably short time after 
being formed into concrete — a property which rendered 
it necessary that only a very small quantity should be 
prepared and laid at one time. 

The following short statement shows the propor- 
tions of gravel and cement used for the concrete : — 

One bushel of cement made 30 bricks = 5 cube feet. 
One barrel of cement made 150 bricks = 25 do. 

The bushel contains 2218 cube inches ; and 30 bricks 
contain 8640 cube inches, leaving 6422 cube inches of 
gravel. Hence the proportion of cement to gravel is 
that of 2218 : 6422, or as 22 to 64, or in round numbers 
about 1 of cement to 3 of gravel. 

Although on account of the breakage and loss sus- 
tained, I am not in possession of sufficient data to 
determine with accuracy the cost of pitching the road 
with bricks, the following estimate of the actual ex- 
pense of forming the concrete bottom will furnish some 
idea of the increased expense which must have attended 
the use of the bricks. 

Four men mixed and laid about 8 lineal yards of 
concrete, 7 feet 6 inches wide and 6 inches deep— this 
being equal to 8 yards x 2| x 0.166 yards = ;]| cube 
yards : therefore 12 men would lay 10 cube yards of 
concrete per day. And dividing this quantity in the 

D 2 



36 

ratio of 11 to 32, we find that 12 men would use per day 

50 bushels of cement and 7.44 cube yards of gravel. 

Hence the following estimate : — 

£ s. d. 
Cement, 50 bushels, at ^s. . . . 5 

(iravel,* 7.44 cube yards, at 8s. . . 2 19 6 

Labourers, 12 men, at 3 . . . . 1 16 

Cost of 10 yards cube, or 12 lineal yards,"] ~ 

15 feet wide, / 

From this we see that the cost of the concrete was 
19^. (yd. per cube yard, or 16s. 3(Z. per lineal yard of 
15 feet wide. It should be noticed, in detailing the 
price of the gravel at 8s. per cube yard, that the unfa- 
vourable circumstances in which the work at Hiffhsrate 
was placed, with reference to the supply of gravel, were 
certainly rather unusual. This material could only be 
obtained at a considerable distance from the works; and 
when dug required great care to be taken in the wash- 
ing and screening, in order to render it perfectly devoid 
of earthy matter before mixing it in the concrete — the 
consequence was, that none of the gravel used in the 
Highgate Archway road cost less per yard than the 
sum mentioned in the preceding estimate. 

It may not be irrelevant to state here, that the Arch- 
way road, to which this description of the work 
relates, was, at the time when it came under the super- 
intendence of Mr. Telford, probably one of the worst 
pieces of road in the kingdom ; and, notwithstanding 
the consultations of engineers and other scientific men 
which had frequently taken place, and the various 
attempts which had been made by them to render this a 

* Gravel at Hi^^hgate, carted from the Thames, incliulinjif tolls, 
&c. would not cost less than is here stated; — if from Fiuchley, or 
that neighhourhood, the carting-, waste, and washing to render it fit 
to mix with cement, made it equally expensive. 



37 

good travelling road, every attempt and trial, although 
attended by the expenditure of" many thousand pounds, 
and almost by the insolvency of the Highgate Archway 
Company, was found to be ineffectual in producing 
anything like a permanent improvement in the condition 
of the road. These various attempts, in fact, were 
dictated by such remarkable ignorance of practical 
principles, that instead of diminishing or removing, it 
has been supposed they actually ended by increasing 
the evil. The geological strata composing the hill 
through which the road is carried, are those of the 
London Clay Basin: they contain a considerable 
mixture of sand and gravel, which being permeable 
materials, are consequently full of water. No syste- 
matic form of draining had ever been considered by the 
scientific men who were consulted ; and as the conse- 
quence of this neglect throughout the winter, and in all 
wet seasons, springs of water were numerous, not only 
in the sides of the excavations but even in the middle 
of the road. It followed, therefore, that any depth of 
covering intended to keep the under stratum from rising 
amongst the gravel or hard material proved quite inef- 
fectual; for as fast as new materials were laid on they 
were pressed into the soft bottom, and mud, clay, and 
sand supplied their places. It has been considered, 
and with great truth, that this piece of road has occa- 
sioned more loss to coach-horse proprietors than any 
other of the same extent either in this or in any other 
country. 

The first determination formed by the authorities of 
the day, after an examination of the road and all tlie 
causes of its defects, was to have the existing surface 
taken entirely out — the whole bed was to be then covered 
with brushwood fagots, and this again to be covered over 
with a good and sufiicient coating of excellent clean 



38 

gravel. That this was far from being a cheap experi- 
ment I need hardly say, whether it were a good one had 
then to be tried. The result naturally followed, which 
any practical man would have foreseen — the road, whilst 
the gravel was loose and the brushwood not compressed, 
was perfectly dry on the surface ; but in consequence 
of the great depth of loose gravel and the elastic nature 
of the brushwood foundation, nothing in my opinion 
could have been better devised for the destruction of 
horses than this truly infamous piece of road.* This 
was the state of things when the road remained un- 
bound ; but as soon as by compression the fagots were 
nearly rotten and made solid, and when it was expected 
that the gravel would bind and a solid surface be 
formed, instead of this the gravel was all nearly ground 
to dust: and certainly out of the expensive materials 
laid on the road there was nothing left but coarse grit. 
This material, I need hardly say, was more unfit to 
carry the tratlic than that which they had taken up to 
make room for it ; and the perishable fagots having now 
become rotten, there was nothing to prevent the mud 
and clay from mixing with the upper covering. The 
whole road was now ten times worse than ever; and a 
material of a character very novel in the history of road- 
making was fixed upon in carrying into efiect a third 
attempt to improve the road. This was no other 
than the refuse or waste chippings of tin ; in order to 
make room for which the old surface was again torn up, 
and the whole bed covered with several inches in depth 
of the tin chippings — a fact which accounted for the 
discovery, when I came to put into execution Mr. 
Telford's plan of forming a cemented bottom, of several 
tons of this material in a state of partial rust, and in 

* The inclination of the liill, on wliich the coaches had to he 
dragged fully iialf a mile, \\as ahout 1 in oO. 



30 

some places knotted and kneaded into the clay, gravel, 
and some small portions of the fagots, which had 
probably not been taken entirely away. I think I need 
hardly say that, notwithstanding the sanguine expecta- 
tions of those who were induced to adopt the novel 
expedient of thus forming an actual metallic sub-stratum 
for the road covering to rest upon, the plan I have just 
described, although no cheaper than those resulting 
from former deliberations, proved as complete a failure 
as any which had preceded. 

It is perfectly well known, that this same Highgate 
Archway road, which had so pertinaciously resisted all 
exertions to improve it on the part of former engineers, 
became, under the management of Mr. Telford, one of 
the very best roads in the kingdom. Mr. M'Neil, I 
believe, showed by means of his friction-testing ma- 
chine, that the power required for draught on this 
road was less than on almost any other which had been 
tried in the same way ; and the superiority thus indi- 
cated, is fully confirmed by the testimony of the stage- 
coachmen and others driving over this part of the 
Holyhead road. 

At the same time, however, that every one at all 
acquainted with the subject is ready to admit the extent 
and importance of the change for the better which has 
taken place in the condition of the Archway road since 
the adoption of the cemented bottom, it follows by no 
means as a necessary consequence, that this improve- 
ment is entirely the effect of the particular kind of foun- 
dation or sub-stratum on which the road material is now 
laid. In order to be convinced of this, and also that, 
knowing all the actual means of improvement, we may 
derive the greatest amount of practical experience, we 
must consider the merit of the very excellent drainage 
devised bv Mr. Telford, and which I believe was on a 



40 

far more extensive scale, and therefore more likely to 
be beneficial than any that had been adopted by bis 
predecessors in the management of this road. As it 
may be useful to the road surveyor generally, to know 
the system of drainage which was at length so efiectu- 
ally acted upon, I shall not hesitate to describe it in 
detail. Along the whole length, and on each side of 
the road, longitudinal side drains were cut, two feet 
wide and four feet deep, below the bed of the road. 
Longitudinal shoulder drains, one foot deep, were also cut 
the whole length of the road on each side of the cemented 
bottom — that is seven feet and a half on each side the 
centre of the road — and transverse mitre drains, opening 
into the shoulder and side drains, were formed across the 
road at intervals of from fifteen to twenty-five yards. The 
deep side drains had a tile and sough cover five inches 
diameter laid in the bottom, and above this the drain 
was filled in eighteen inches wide with clean stones, 
the space of six inches between the sides of the 
drain and the road side being filled with clay and well 
pounded. The other drains had no sough or tile, but 
like the side drains were filled to the top with clean 
stones. 

It was the natural result of a drainage so complete 
as that which I have described, that water falling on 
surface of the road could not lodge in the bottom, and 
in this way keep the road in a soft and wet state, but 
would immediately be conveyed into the shoulder or 
side drains quite clear of the road ; and with respect to 
water which arose in springs at the side of the road, 
this was provided for by the side drains, which cflectu- 
ally cut ofl' all these springs and diverted them along 
the road side. 

But in reverting lo the state of this road before the 
existence of the drains, we are presented with a wide 



41 

contrast to that in which it was afterwards placed by 
the judicious measures of Mr. Telford. It was formerly 
found [that the natural springs, which abundantly 
existed in the high ground on each side of the road, 
discharged themselves in the bottom and sides of the 
excavation; and before the necessary means were taken 
to prevent them reaching this situation, the bed of the 
road remained constantly wet and saturated with water. 
This iSy a case by no means peculiar to the Highgate 
road : I have met with it in many others, where, as in 
the] present instance, the construction of deep and ca- 
pacious side drains, which acted as channels to cut olF 
and divert the water from entering the confines of the 
road, proved the only effectual remedy. We may now 
readily conceive the grand secret of all the previous 
failures in the various attempts made to improve this 
road ; — it is perfectly evident, that so long as the clayey 
bed of the road continued to be saturated with water, 
it was capable of displacement by any weight passing 
over it ; and thus no means could be invented to prevent 
it from rising, and mixing with each successive body of 
materials laid upon the road. 



42 



CHAPTER V. 

On the Use of Concrete composed of Gravel and Lime, as 
a Foundation for Roads in places where pitching 
Stones cannot be procured. 

The descriptions of stone which might with pro- 
priety be used for a pitched foundation are so various, 
and are so extensively found throughout England, that 
in few counties the surveyors are without the means of 
adopting that method of securing a hard substantial 
j.oad. Nevertheless, in the neighbourhood of London, 
and in some other districts, particularly Norfolk, Suf- 
folk, Cambridge, and the adjoining counties, where the 
place of the stratified rocks is supplied by beds of gravel, 
it will be found an expensive, and in some cases almost 
an impracticable proceeding, to procure and lay down 
stones, as a pitclied foundation for the road material 
to rest upon. I should by no means recommend the 
adoption of this kind of foundation in places where the 
expense would exceed the price of concrete, or say 
from J3.v. to Qs. per cubic yard ; and shall therefore now 
proceed to point out the way in which gravel itself may 
be applied to the purpose of securing as hard and tirm 
a road, and one as little subject to destruction, as any 
that could be formed in a country where the hardest 
kinds of stone are within the reach of the surveyor. 

The concrete I am about to describe will be difFerent 
in one important particular from that used on the High- 
gate Archway road, although intended to effect the same 
object, of preventing the sub-stratum on which the road 



4:3 

is formed from being displaced, and from rising up to 
mix with the superior stratum of road material. In 
some respects the concrete of lime, although much 
cheaper than that formed with cement, possesses ad- 
vantages over the latter ; but if it should hence be 
inferred, that the expense of the cemented bottom at 
Highgate was on this account unnecessary and waste- 
ful, it must be remembered, as some apology, that the 
virtues of lime in forming concrete were not then so 
extensively known as they have since become ; and 
had this work now to be performed, I have no doubt 
that the concrete of lime would be used in preference 
to cement. 

The principal difference between the two kinds of 
concrete, arises from the liability of cement to break 
and crumble when exposed to pressure, to percussion, 
or to any other violent disturbing force ; and when 
once a fracture has taken place, it is a characteristic 
of cement that the parts will never again unite. 
Therefore it is that cement, although extremely valu- 
able as a means of forming a very solid artificial stone, 
by uniting into one mass a body of broken stone or 
pebbles — and although it possesses the remarkable pro- 
perty of setting in all situations, even under water, in a 
very short time after its mixture — is yet hardly a safe 
material to use in any place where it is subject to the 
disturbances already mentioned, by which the adhesion 
of its constituent parts will certainly be destroyed ; and 
this having once taken place the whole binding virtue of 
the cement is gone. 

I regret that I have never had an opportunity of 
seeing a specimen of the cemented bottom taken from 
the Highgate Archway road, after it had been laid 
down a sufiicient length of time to prove its durability. 
If such a specimen could be procured, it is not impro- 



44 

bable that it would be found in a fractured condition ; 
and this would of course prove a very strong confirma- 
tion of the notion with which I am now very strongly 
impressed, that lime concrete, from the greater degree 
of toughness it possesses, and the consequent absence 
of that brittleness and tendency to break which are so 
remarkable in cement, is actually much the superior 
material of the two as a foundation for roads. 

The use of lime concrete, although an introduction 
of modern times, and certainly one of rather a novel 
character, derives its real origin from a very remote 
period. We have indisputable evidence that the Ro- 
mans in constructing their military ways, particularly 
in France, adopted the practice of forming a concrete 
foundation composed of gravel and lime, on which also 
they placed large stones as a pavement. The conse- 
quence of a construction so solid has been, that in 
many parts of Europe the original bed or crust of the 
Roman roads is not at the present day entirely worn 
down, even after a lapse of fifteen centuries. 

With the view of affording a modem example in 
which lime concrete has been used, I would refer to the 
Brixton road, where a concrete composed of gravel 
and lime has been recently applied by Mr. Charles 
Penfold, surveyor to the trust. In this case the pro- 
portion of gravel to lime is that of 4 to 1. The lime is 
obtained from Merstham or Dorking, and before being 
used is thoroughly ground to powder. The concrete is 
made on the surface of the road, and great care taken, 
when the water is added, that every particle of the lime 
is properly slaked and saturated. The bed of concrete 
having been spread to the depth of six inches over the 
half breadth of the road, the surface is then covered over 
with six inches of good hard gravel or broken stone, 
and this depth is laid on in two courses of three inches 



45 

at a time, the first course being frequently laid on a 
few hours after the concrete lias been placed in the 
road. The carriages however are not on any account 
allowed to pass over it, until the concrete has become 
sufficiently hard and solid to carry the traffic, without 
suffering the road material to sink and be pressed into 
the body of concrete. On the other hand, the covering 
of gravel is always laid on before the concrete has be- 
come quite hard, in order to admit of a more perfect 
binding and junction between the two beds, than would 
take place if the concrete were suffered to become hard 
before laying on the first covering. The beneficial 
effect arising from the practice of laying on the gravel 
exactly at the proper time is, that the lower stones, 
pressed by their own weight and by those above them, 
sink partially into the concrete, and thus remain fixed 
in a matrix, from which they could not easily be dis- 
lodged. The lower pebbles being thus fixed, and their 
rolling motion consequently prevented, an immediate 
tendency to bind is communicated to the rest of the 
material — a fact which must be evident, if we consider 
that the state called binding, or rather that produced by 
the binding, is nothing more than the solidity arising 
from the complete fixing and wedging of every part of 
the covering, so that the pebbles no longer possess the 
power of moving about and rubbing against each other. 
It is found that, in a very few days after the first layer 
has been run upon, the other or top covering may be 
applied, and shortly afterwards the concrete and the 
whole body of road material becomes perfectly solid 
from top to bottom. The contrast thus presented to 
the length of time and trouble required to effect the 
binding of road materials, where the whole mass is laid 
on loose, is alone a very strong recommendation in 
favour of the concrete. 



46 

The experiment of using concrete on tlie Brixton 
road, although not at present on a very extensive scale, 
has been tried under circumstances very far from 
favourable, and on a part of the road which had hitherto 
baffled every attempt to make it solid. Since the con- 
crete has been laid down, however, there is not a 
firmer piece of road in the whole trust ; and from the 
success of this and other trials made by Mr. Penfold, 
but which I have not seen, I believe it is his intention 
to recommend it in a general and extensive way to 
several trusts under whom he acts. 

The use of concrete for building purposes, where 
great solidity is required, has now become very general 
and cannot be too strongly recommended. We have 
now examples of a very extensive sea-wall, and of 
several dock and wharf-walls, and even of a church, 
built entirely of concrete. In some of these cases, par- 
ticularly in that of the sea-wall at Brighton, the lime 
used for the concrete is slightly hydraulic, possessing 
therefore the property of setting under water. In some 
roads where the concrete is laid upon a damp sub-soil 
this quality will be useful; but it is by no means essen- 
tial to the formation of a perfect concrete, as any 
description of hard strong stone lime will admirably 
answer the purpose. From the experience of the sea- 
wall at Brighton, we derive the knowledge of a fact, 
which may prove of some value to those who may 
have occasion to use concrete in the neighbourhood of 
the coast, namely, that the salt water of the sea makes 
excellent mortar, and the pebbles of tho sea shore form 
excellent material for mixing with the lime to make 
concrete. There is, therefore, good reason lor sup- 
posing the prejudice to be groundless, which is enter- 
tained by many engineers and architects, against the 
employment of any material containing saline particles, 
in making either mortar or concrete. 



47 

I should here mention, that while the improvement 
described in the preceding chapter was in progress on 
the Highgate Archway road, one particular spot of the 
road about four feet square, near the Wellington Inn, 
being found extremely soft and elastic, T tried here on 
my own responsibility a concrete composed of gravel 
and blue lias stone lime, which was substituted for the 
cement concrete, and the result of this certainly was to 
render that part of the road as perfect as all the rest. 

In consequence of this trial, strengthened by a very 
strong notion of my own that lime concrete would be 
found at least equally etfective with that of cement, I 
consulted Mr. Rhodes, civil engineer, on the subject, 
as he had always taken great interest in the improve- 
ment of this road ; and his opinion determined me to 
request permission from Mr. Telford to lay down a 
small quantity of the lias lime concrete on another 
part of the work. Mr. Telford having afterwards agreed 
to this at the further suggestion of Mr. Rhodes and Mr. 
M'Neil, it was accordingly tried on a short length of the 
road near the summit of the hill. The trial, I should 
state, was not made until after I had finished my con- 
tract for the work ; and I regret to say, that the time 
chosen was very injudicious, and no precautions to 
protect it from the weather being taken, the frost com- 
pletely destroyed the lime, and the concrete was never 
allowed properly to set. In consequence of this failure, 
it was reported that the lime concrete could not be 
used as a substitute for the cemented bottom; and not- 
withstanding the completely successful and very satis- 
factory trial I had myself made at the Wellington Inn, 
the idea of using lime concrete was abandoned. It will 
only be fair towards Mr. M'Neil, however, to acquit 
him entirely of all blame for the failure of the trial made 
after I had left the work. I believe it was his intention 



48 

fairly to have tried the lime concrete ; but from some 
cause or other with which I am not acquainted, he was 
prevented from attending to it himself; and the person 
he entrusted having neglected it, I do not think Mr. 
M'Neil ever knew the cause of the failure. 

Without however drawing any inference as to the 
value of lime concrete, from the trials made on the 
Highgate road, I am decidedly of opinion that this 
material, if generally adopted as a foundation for roads, 
will effect one of the greatest improvements that has 
for many years been presented to the notice of the 
public. In the neighbourhood of the metropolis parti- 
cularly, where durable materials are so exceedingly 
expensive, and where the Thames gravel can be had at 
such a cheap rate, the expense of constructing the best 
description of road will be very much diminished. The 
Thames gravel can be delivered, at a distance of from 
two to three miles from the river, at about 3.s. per cubic 
yard; hard flints and well prepared pit gravel at about 
6s. or 6s. 6d. per yard; Guernsey granite, Mountsorrel, 
Dartmoor, Hay tor, or Scotch granite, from 15s. to 20s. 
per cube yard. I am clearly of opinion, that the first of 
these materials — the river gravel — ought never to be 
used as an upper covering or surface for any road of 
much traffic, even if it could be had for nothing. From 
its extremely brittle nature, it not only crumbles and 
breaks to pieces immediately when pressure comes 
upon it, but it actually is decomposed, and crumbles 
into sand and grit when acted upon by the alternations 
of the weather alone. On accoimtalso of its round and 
smooth surfaces, which are perfectly divested of all 
material of an adhesive nature, the binding of this 
gravel is entirely out of the question until it be made 
angular ; and this never happens except when the whole 
is ground into such small particles as to render it quite 



49 

unfit for a carriage road. The consequence is, that this 
gravel no sooner begins to bind or set, than the first rain 
or thaw, after ever so slight a frost, renders it quite im- 
passable ; and hence it is, that where this material is 
much used on the metropolitan roads, the public can 
never have the advantages of a solid, hard, and firm 
surface for any length of time. Even in the very best 
summer weather such a road cannot stand many days; 
the public are therefore constantly annoyed, either with 
a new covering, which occasions an immense friction 
and great wear and tear of horses and gear of every 
description, or they have to travel on a road which is 
so soft that the wheels of carriages sink into it with 
perfect facility — in either case the friction, and conse- 
quent destruction of horses, carriages, and harness, and 
the annoyance to those who travel on it, must be exces- 
sive. When we take further into consideration the 
number of men who must be in constant attendance to 
rake in the ruts, and to clear the road of the useless 
materials when ground to pieces, and also the constant 
expense of laying on new materials, I think few will 
be inclined to dispute with me the impolicy of using 
river gravel as an upper covering on the metropolitan 
roads. Since, then, it cannot be profitably or judi- 
ciously used as an upper covering, it would be obvi- 
ously improper to apply it as a bed on which to place 
the harder stone, which forms the road material. This 
must be evident, from the, well known fact, that the 
binding and setting of any road covering, however deep, 
always commences at the bottom of the material ; and 
it will occur to every one who considers the subject, 
that no binding of a stronger and heavier material can 
take place on another of a softer or lighter description 
than itself; because the upper material, being the 
harder and stronger of the two, will sink down and 

E 



50 

press the other aside instead of uniting with and binding 
into it. In this way the softer material would evidently 
very soon be destroyed; because, until the binding of a 
road covering takes place, the friction and rubbing of 
the stones amongst themselves is very considerable and 
very destructive. The effect of this may readily be 
conceived in the case of a soft brittle material like the 
river gravel, mixed up as it soon would be with a hard 
silicious granite or whinstone. Experience in fact has 
shown, in a great number of cases, that it is quite im- 
possible to produce effectual binding unless the bottom 
be solid, and to a certain extent unyielding ; and hence, 
if two or more varieties of materials are to be used in 
the covering, the hardest must be placed in the bottom 
and not on the top. 

From these considerations it would evidently be a 
most important object, if an inferior and otherwise 
worthless material, such as river gravel, could be so 
applied in roadmaking as to form a hard unyielding 
body, on which a covering of hard stone might be laid, 
without producing the same effects as if laid on a loose 
bed of the gravel. It is on this ground that I beg to 
recommend the use of concrete, composed of lime and 
river gravel, which being entirely divested of earthy 
matter, is probably one of the best materials that can 
be found for forming a strong and durable concrete. 
This kind of gravel has been used for the concrete 
placed in the foundations of many important buildings ; 
amongst which I may mention particularly, the Peni- 
tentiary at Millbank, where a concrete foundation was 
laid by my father, the late Mr. John Hughes. From a 
long experience of the value of concrete, in this and 
other situations, I am persuaded that this material will 
form one of the best foundations for a road that has 
ever been tried. The nature of the lime, which com- 



51 

poses so principal an ingredient in this concrete, ren- 
dering it quite impervious to water, no springs can 
break up through it, and this in damp situations is an 
extremely useful property. I have already alluded to 
the toughness of lime concrete ; and I think I may add, 
that when this material has once become well set its 
hardness can scarcely be exceeded — it then becomes in 
fact perfect stone. As an instance in corroboration of 
this, I would mention, that before Mr. Telford deter- 
mined on using concrete so extensively, in the foun- 
dations under some of those heavy breast-walls and 
warehouses at the St. Katherine's Docks, a specimen 
of the concrete, which I have already stated was some 
years before placed under the Penitentiary, was by 
authority allowed to be dug out. I saw a part of this 
specimen, and I never in my life witnessed any material 
resembling so nearly the Pudding-stone rock — a con- 
glomerate Avhich is always considered an exceedingly 
hard and perfect stone. 

I should recommend for all the principal roads near 
London — after all the supplies of water from the sides 
as well as that falling on the road have been properly 
intercepted by longitudinal side drains and transverse 
ones leading into them, and occurring as often as the 
nature of the sub-soil may require — that a bed of lime 
concrete six inches in thickness, mixed as already 
described, be laid all over the breadth of the road ; and 
that this bed be afterwards covered with six inches of 
the best flint or pit gravel that can be procured, in two 
courses of three inches at a time ; or with, what in my 
opinion would be a much more lasting and serviceable 
material, four inches of broken granite stone : and I am 
convinced that a road so constructed, however bad the 
under stratum may be, will prove one of the hardest, 

E 2 



52 

most durable, and at the same time one of the cheapest 
roads ever formed in the neighbourhood of London. 

I would here however suggest, that the surveyor (or 
whoever may have charge of a road so constructed) 
ought never to admit of the covering being worn down, 
so as to permit the concrete to be acted upon or in any 
manner disturbed ; but as soon as the upper surface is 
worn down to within two inches, or at most to within 
one inch of the concrete, a new covering the same thick- 
ness as before should be immediately laid on. 

It may not be considered very foreign to this subject 
to remark, that in gentlemen's parks, gardens, and plea- 
sure-grounds, it is exceedingly difficult, if not imprac- 
ticable, to make ornamental carriage roads or private 
walks by the old system of laying on loose gravel or 
broken stones; for whatever pains be taken in selecting 
the best kind of gravel and afterwards in forming and 
rolling, worms will find their way through ajid destroy 
it by depositing a portion of adhesive earth wherever 
they work to the surface ; and these deposits are so 
numerous, particularly in the autumn and through the 
winter and spring of the year, that' in the case of the 
carriage-roads, this earthy material first adheres to the 
rims of the wheels, and then again sticking to the gravel, 
tears up the whole surface to the entire destruction of 
the road. Garden walks from this cause frequently 
cannot be traversed with any pleasure — the dirt adheres 
to the feet and is so exceedingly unpleasant, that such 
roads and walks, instead of having a hard, clean, and 
smooth surface, become dirty and unsightly in the ex- 
treme. I would recommend in such places, that the 
roads and paths should uniformly he made with a con- 
crete bottom of only a very few inches in thickness; say 
three inches for carriage roads and two inches for paths, 



53 

and with a slight covering of binding gravel on the top. 
This system, I think, would effectually prevent the roads 
from being destroyed in the manner I have described ; 
for independent of the antipathy which the worm, and I 
may add every description of insect, entertains against 
lime, and notwithstanding their capabilities of boring, 
they never could penetrate half an inch into the con- 
crete. As an instance of the perseverance of worms, 
and of the mischiefs they sometimes occasion, T have 
myself, during a very dry hot summer, met with them in 
canal excavations, four feet below the surface in hard 
clay ; and I have known them penetrate afterwards out 
of this depth and through three feet of clay puddle, 
thereby actually occasioning leakage in the canal. 



54 



CHAPTER VI. 

On the Drainage of Roads. 

Of all the considerations which claim the attention 
of the practical roadmaker, that of complete and effec- 
tive drainage is the most important, and generally the 
first which should be attended to. Although some 
roads are far more favourably situated than others with 
respect to the extent of artificial drainage required, it 
is quite certain that no road has any chance of becoming 
perfect unless the under stratum be rendered perfectly 
dry, either by natural or artificial means. The very 
best materials ever employed to form the crust of a road 
will be entirely thrown away, unless this very essential 
part of the work be first performed ; and on the other 
hand, many very excellent roads owe their superiority 
almost entirely to the beneficial effects of good drainage. 
In the formation of a new road, or in improving those 
already made, no money is so well laid out as that ex- 
pended in procuring perfect drainage ; and what may at 
first sight appear to be an unnecessary outlay, will in 
the end be found the most economical application of 
capital that can be devised. 

The particular kind of drainage required for roads 
must of course be determined by local and other 
circumstances; and it may now be advisable to con- 
sider some of the varieties of drainage to which these 
will give rise. 

When a road is formed on a level with the ground 
on each side, there will seldom be found much diffi- 



55 

culty in preventing the accumulation of water. In this 
case the road will not of course intersect any natural 
springs, which are often found exceedingly troublesome 
in other situations, and the only water to be carried off 
by the drains, is that falling on the surface of the road 
in the form of rain and snow. The most favourable 
circumstances under which a road can be placed for 
effecting this, are those in which a longitudinal inclina- 
tion of not less than six or eight feet in a mile exists 
in the direction of the road. This fall of 1 in 880 or 1 
in 660, although so nearly horizontal as to be scarcely 
perceptible, will be sufficient to carry off the water; but 
it is advisable if possible to obtain a greater fall, which 
will add very little to the draught of the road. In no 
case however should the fall of the road be less than 
six feet in a mile ; and where a greater cannot be ob- 
tained the utmost attention must be paid to the state of 
the side drains, for unless these be kept well cleaned 
out, and unobstructed by weeds or other matters, it is 
obvious that the water will not pass off. If the bed of 
the road be formed with a regular convexity, as de- 
scribed in the second chapter, there will be no necessity 
for a centre longitudinal drain ; nor after the road has be- 
come hardened will transverse mitre drains be required, 
because the water which may soak through the upper 
covering will naturally run off to the side drains. Should 
the water be found to stagnate in pools over any part 
of the side drains, the labourer in charge of the road 
should, as soon as he discovers this, drive the point of his 
pickaxe through the upper covering down to the rubble 
stones with which the drains are filled, when the water 
will find its way off the surface and make a ready 
escape by means of the side drain. As the field drains 
should always be lower than the side drains, and gene- 
rally will be the lowest drainage that can be had for th-^ 



56 

road, it will be necessary, particularly where the longi- 
tudinal fall of the road is not considerable, to make 
frequent communications between the side drains and 
the outer field drains. These communications may be 
made at intervals of about forty or fifty yards, and may 
either consist of earthen pipes laid across under the 
mound and under the footpath or verge, or of brick 
drains, having an area or opening of about eighteen 
square inches. The field drains, placed on the outside 
of the mound or quickset bank, will of course be open 
drains, and will serve to drain the adjacent lands as 
well as the road itself. The side drains, however, 
formed within the limits of the road, should be filled 
with clean carefully selected rubble stones, not less in 
size than a cube of three inches nor larger than a cube 
of five inches, that is, containing from about thirty to 
one hundred cubical inches. These drains have some- 
times a fiat and sough tile placed in the bottom before 
the rubble stones are filled in. I should however re- 
commend the following construction, namely, a flat tile 
in the bottom, the sides to be bricks on edge placed on 
the flat tile, and the top a tile similar to that in the 
bottom. I prefer bricks for the sides of the drain, be- 
cause the sough tiles are so liable to breakage, an 
objection which does not apply to the flat tiles. These 
latter ought to be used for the bottom and top of the 
drain, because they occupy less space than bricks, and 
consequently leave more room for the rubble stones. 
The bricks may be placed on the bottom tile about four 
inches apart, so as to make the opening of the drain 
about eighteen square inches; and it will be advisable 
to leave a space of about a quarter of an inch at the 
end of each covering tile, to allow the water percolating 
through the rubble stones more freely to enter the brick 
drain. The side drains should always be formed at 



57 

least a foot below the bed of the roadway, and they 
should never be made without either the sough and tile, 
or the brick drain above described; because, in addition 
to the facility thus given to the flowing of the water, the 
bricks and tiles prevent the rubble stones from being 
pressed, and sinking into the ground, as they would 
otherwise be likely to do. 

Notwithstanding, however, all the precautions that 
can be taken, it will sometimes be found that the very 
best constructed drains become choked up and prevent 
the water from escaping. In such a case, the occurrence 
of which will soon be evident from the appearance of 
water on the surface immediately on the top of the 
drain, and sometimes on the road itself, the workmen 
should immediately proceed to open the suspected 
drain, a little lower down than where the water is ob- 
served to stop or break out upon the road. The drain 
will now appear dry at this point, demonstrating that 
the flow of water is here interrupted, but the drainage 
below is perfect. The stones and tiles must then be 
regularly cleaned out, and when replaced the drain will 
act as well as ever. Although a stoppage in one of the 
side drains, if allowed to continue, would soon destroy 
a good road, and particularly if it happen in wet 
weather, yet nothing is easier when once discovered 
than to efiect the cure as above described. 

The next case of drainage to be considered is, where 
the road has to be excavated below the natural ground 
surface, a situation in which the difficulties arising from 
the presence of water, and the necessity of preventing 
it from disturbing the bed of the road, are far more nu- 
merous than where the road is formed on a level with 
the natural surface. Almost every stratification with 
which we are acquainted, except clay and some of the 
very hard rocks, are capable of being penetrated by 



58 

water, which percolates through them until it arrives at 
some low level where it can be discharged. It is im- 
possible, however, from merely knowing the nature of a 
stratum to be cut through, to predict with anything like 
certainty whether it will be found to contain water. 
This depends so much upon its position with respect to 
other strata, that it is only upon a view of the situation, 
and an accurate knowledge of all the circumstances, 
that a correct judgment can be arrived at. For in- 

4 stance, a bed of sand 
B^.^,^--^7j;^^;frm:^ or gravel, in the po- 
Clay. sition shown in the 

annexed sketch, will 
probably receive the water falling on the crown of the 
hill, which will then pass through it from A to B. 
where it may discharge into the valley. But if the bed 
of sand or gravel be found in the shape of a basin, as 

in Jig. 2, it is obvious 
that all the Water in 
^ the sand cannot pass 
Clat/. off, because its flow is 

impeded by the underlying bed of clay. The hori- 
zontal line A B, will represent the lowest level of 
drainage, and below this level we may expect to find 
the stratification full of water. 

Although the relative positions of different strata 
are exceedingly variable, it will generally be found that 
any particular bed of porous gravel, sand, or chalk is 
wet or dry, according as the water which soaks into it 
in one place, is or is not dammed up by some stratum 
impervious to water, of which nature is almost every 
variety of clay. The deep excavations made for the 
canals, and more recently for some railways, aflbrd 
remarkable instances of the truth and propriety of this 
distinction. For instance, the borings made on the line 




69 

of the Brighton Railway, in the neighbourhood of Merst- 
ham and Oxtead, as well as the quarries which are 
extensively worked at various places along the Surrey 
chalk range, showed the chalk to be almost quite dry ; 
whereas on the London and Birmingham Railway, 
in the neighbourhood of Tring, the chalk is entirely 
saturated with water, and although belonging to the 
same formation as the Surrey chalk, is extremely dif- 
ferent in appearance and texture, being generally of a 
dingy cream colour, and very much shattered for a con- 
siderable depth. The reason of the difference is simply 
this, that in Surrey the gault brick earth, a strong 
tenacious clay which underlies the chalk in both cases 
at its outcrop, rises very little above the level of the 
lower chalk beds, and therefore the water percolating 
through the chalk is allowed to escape over the clay, 
which it accordingly does, forming several small streams 
flowing southward. But at Tring the gault rises to a 
considerable height above the level of the lower chalk 
beds, thereby damming back the water which remains 
in the chalk, at least as high as the level of a horizontal 
line drawn from the junction of the gault and chalk 
strata. Hence it is easy to account for the complete 
saturation of the chalk in this part of the country ; and 
on the same grounds, we perceive the origin of the vast 
stream of water which was found to issue from the chalk 
excavation at Tring, as soon as the cutting was carried 
through the bed of gault, and the water thus provided 
with a channel of escape from the chalk. 

In cutting through any porous stratification, where 
the water has been held back as at Tring, by an under- 
lying bed which has also to be cut through, it is obvious 
that the excavation itself will serve to drain the porous 
stratum as low as the level of the road ; and it will, 
therefore, only be necessary to make side drains of 



GO 

rather larger dimensions than in ordinary cases; and it 
will sometimes be found a very excellent and necessary 
expedient to lay down, along the centre of the cutting, 
a culvert or barrel drain of brick, into which communi- 
cations should be made from the side drains, at inter- 
vals of twenty or thirty yards. The opening which 
the barrel drain should have will depend upon the 
quantity of water; but eighteen inches or two feet 
will be found sufficient in most cases ; and the bottom 
of the barrel drain should always be sunk at least 
a foot lower than the bottom of the side drains, in 
order that the water from these may flow readily into 
the centre drain. 

But perhaps the most difficult kind of excavations 
to drain, are those which so frequently occur through a 
stratification of clay alternating with beds of sand or 
gravel. A road cut to the depth of twenty or thirty feet 
may intersect a great number of these beds, from which 
the water will issue on the slopes, and if not properly 
guarded against, will produce the most injurious con- 
sequences. This is precisely the case with Highgate 
hill, particularly on the south side of the Archway : 
the water contained in the porous strata breaks out all 
over the slopes, carrying down portions of the loose 
running sand or gravel, and thus undermining large 
masses of earth, which consequently slip down into 
the road. Various expedients have been resorted to 
for the purpose of preserving the slopes, preventing 
slips, and protecting the road from the water breaking 
out on the slopes. At Highgate, and other places, 
wells or shafts, about four feet in diameter, have been 
sunk at several parts of the slopes, into which the 
water is allowed to drain, until it meets at the bottom 
with some porous bed of sand or loose gravel lower 
than the road, (hrough which it can pass olf away from 



61 

the road and the slopes. This method, although very 
expensive, has seldom been found a very eflectual 
remedy. In my opinion, a much better plan would be 
to form rubble drains along the face of the slopes, in 
order to intercept, if possible, all the water which 
breaks out, and conduct it into the side drains at the 
foot of the slopes. No general rule can be laid down 
for the direction and inclination which should be given 
to these drains ; but they should be so projected as to 
intersect as many of the springs as possible, at the 
same time that a sufficient fall must be given to allow 
the water to pass freely along them. I have myself 
very commonly adopted this plan in canal and road 
excavations, particularly on the Union Canal, in Scot- 
land, and at Forty-mile hill, on the London and Holy- 
head road, aud have always found it succeed ad- 
mirably. The drains should be filled with the same 
kind of rubble stones as already described for the road- 
side drains, and then covered with a thin layer of 
brushwood, over which earth or mould may be spread, 
so that no external appearance of drainage will be 
visible ; and in almost all situations where water is 
found to break out on the surface of the slopes, this 
method of drainage will prove remarkably effective. 

In all excavations I should make the drains at the 
foot of the slopes of greater depth and area than the 
side drains for a surface road; and it will also be 
necessary to form catchwater drains at the top of the 
slopes, to intercept the surface water, which would 
otherwise run down the slopes. The form and dimen- 
sions of these drains must in some degree depend upon 
the nature of the ground in which they are made. A 
width of three feet at top, and one foot six inches at 
bottom, and depth of two feet, will in most cases be 
found sufticient. 



62 

It would obviously be impossible, within any reason- 
able limits, to give rules for all cases where water is 
met with in road excavations; but I have no hesitation 
in asserting (as the result of a long course of practical 
and constant experience in matters of this kind,) that 
there is no case of drainage so difficult that some 
means cannot be found completely to overcome any 
obstacles that may arise ; and rarely indeed is a tract 
of land so unsound, that it cannot by judicious manage- 
ment be rendered sufficiently solid and firm to bear the 
weight of any road which has to be made through it. 

Instances frequently occur in which the adoption 
of some very simple expedient will eff"ectually cause 
the water to disappear from a place where it is found 
troublesome. This may be done where water is found 
resting upon clay, beneath which exists any stratum of 
a porous nature ; for if an opening be made through 
the clay, the water will usually escape, and filter 
through the inferior stratum. In this way many large 
tracts of land have been drained ; and it will be ad- 
visable in all cases, before any expense be incurred in 
constructing drains or driving headings, to consider 
whether, from the nature of the sub-stratum, it is likely 
that a shaft sunk down a few feet will efi'ect the 
purpose required. 

The third and last case of drainage to be considered 
is, where the road has been raised on embankment above 
the natural surface of the ground. Here it is obvious, 
that the only danger to be apprehended from water is 
that which may be occasioned by rain or snow falling 
on the surface of the road. Should the water succeed 
in penetrating through the upper covering of the road, 
and sink into the body of the embankment, it will pass 
downwards without doing much mischief; but if the 
embankment be not composed of porous material, but 



63 

consist of clay, which may perhaps have been much 
compressed, and as it were kneaded and puddled by 
the wheels of carts and waggons during the filling of 
the embankment, the water will not so readily sink into 
it, but be held up amongst the boxing or road metal. 
Under these circumstances, it is necessary that some 
kind of drainage should be provided. If the road have 
a longitudinal inclination, the drains to be formed in 
the road metal of the embankment should be of the 
kind called mitre drains ; that is, they should not be 
formed across the road at right angles to its direction, 
but should be formed obliquely from the centre to the 
sides, in order that they may have a fall in the same 
direction as the road itself. The mitre drains are 
usually cut a foot wide and a foot deep below the bed 
of the road, and filled with clean stones, of the same 
description as those described for the side drains in 
cuttings. Mitre drains, however, are only necessary 
whilst the road metal or covering remains loose and 
unbound ; because, when it has once become hard and 
solid, the water falling on the surface will not pene- 
trate into it, but run oflF towards the sides: hence I 
should never advise the formation of these drains, 
except where heavy rains are expected, before the road 
metal can have time to set and harden ; and even then, 
as before stated, they are only necessary on embank- 
ments formed of clay, which has been rendered im- 
pervious to water. I should think it possible, in all 
cases, to lay on the road metalling even on a clay 
embankment, and to cause it to set and become hard 
before it can be injured by rain ; and whenever this can 
be done the mitre drains may be dispensed with. 
Suppose now the road surface to be formed hard and 
solid, so that the water which falls on it will not sink 
in, but run ofi" towards the sides ; if the road has been 



04 

made without footpath or verge, the water will of 
course run off the top of the embankment and down 
the sides of the slopes ; but if on opposite sides of the 
carriage-way a footpath and verge have been formed, 
drains must be laid under these at intervals, to conduct 
the water from the sides of the road on to the slopes. 
These drains may be similar to those described for the 
road on a level with the ground surface, and may be 
placed at the same interval apart, namely, forty or fifty 
yards. From the points where these drains open on 
the slopes, it is an excellent plan to form paved chan- 
nels directly down the slopes, in order to preserve the 
latter, and prevent the water from spreading over their 
surface, and sinking into the embankment. These 
paved channels may be formed with any rough pitching 
stones, and should be made about two feet wide, with 
a concavity or dish in the centre of about four inches ; 
and to add to the finished appearance of the slopes, 
the sides of these channels may be defined by a row of 
grass sods, laid with the green sward uppermost. 



G5 



CHAPTER VII. 

On the Means of comparing different Roads, and of 
estimating the Effect of Inclinations, and the other 
Causes producing resistance to Motion. 

No pretence is here made of being able to afford the 
engineer any information in the practice of a part of 
his profession, which is commonly executed with so 
much ability and judgment, as the laying down and 
tracing through a district of country the line of a new 
road. It will obviously be travelling beyond the limits 
in view, to enter upon the general engineering considera- 
tions which may present themselves, to determine the 
merits and defects of particular new lines, and finally 
to turn the balance of opinion in favour of that one 
which is found, upon investigation, to possess the 
most decisive merits. These considerations are, to a 
certain extent, similar and mutually applicable in the 
several cases of canals, railways, and common roads. 
They involve the necessity of land surveys, from which 
the features of the country, in respect of property and 
population, must be accurately known and delineated. 
Surveys, also, of levels are absolutely necessary, that 
sections of the country may be made in various direc- 
tions, to show the heights of summits and depths of 
valleys to be intersected, and generally to determine 
the nature of the inclinations of which the new road is 

F 



6G 

to consist. The judgment of the engineer is formed 
with these data before him ; and in all works of im- 
portance that judgment ought to be based upon a 
thorough practical experience, aided by a perfect know- 
ledge and deliberate consideration of all the various 
circumstances in which the new work is to be placed, 
or which may be brought to bear upon its future posi- 
tion. The attempt to lay down any general rules on a 
subject capable of such extended ramification, would 
probably fail to convey much useful information ; but 
with a view to the comparison of roads already exist- 
ing, and in order to arrive at some simple means of 
appreciating the force of draught required on different 
roads, and on different parts of the same road, it 
may be useful to consider the effects of gravity and 
friction in producing increase or diminution of the 
draught. 

The former of these, namely gravity, is a force 
very easily estimated. On a level plane or horizontal 
road, the entire weight of any carriage is supported by 
the road itself, and therefore the moving power is not 
taxed to support any of the weight ; hence in this case 
there is no resistance whatever by reason of gravity, 
the only retarding force being that of friction, or the 
resistance to motion occasioned by the rugged uneven 
surface of the road. On a plane inclined to the horizon, 
the eflect, with respect to the power of traction required, 
is the same as if the weight be only partially supported 
by the road. The amount so supported is equal to the 
whole weight, minus that portion of it denoted by the 
inclination of the plane ; thus on an inclination of 1 in 
30, expressed by the fraction -^\, the amount |g of the 
weight is supported by the road, and the remaining -^^^ 
has to be supported by the moving power. The conse- 



67 

quence is that, calling the natural sine of the inclina- 
tion of any plane the quotient of the height divided by 
the length, in the case of a weight ascending the plane, 
the force of traction required is equal to the friction 
increased by the product of the weight multiplied by the 
natural sine of the inclination ; and in the case of a 
weight descending, the force of traction required is 
equal to the friction diminished by the same product. 

The friction of a carriage moving on a road is 
expressed by that weight which, being connected with 
it, suspended over a pulley, and allowed freely to de- 
scend, will drag the carriage along a level road. That 
weight is usually stated which in this way is capable 
of dragging a ton ; and various experiments have been 
made to determine the amount of this weight, or the 
friction of a ton on different kinds of road. Sir Henry 
Parnell, in his Treatise on Roads, gives the following 
table : 

Table of Friction. In lbs. per ton. 

On a well made pavement 33 

On a broken stone surface, or old flint road ... 65 

On a gravel road ... 147 

On a broken stone road, with a rough pavement 

foundation 46 

On a broken stone surface upon a bottoming of con- 
crete, formed of Parker's cement and gravel . . 46 

These results have been principally derived from 
experiments with Mr. McNeil's dynamometer, and must 
be understood as only applicable to very slow velocities. 
On all surfaces where the friction is considerable, the 
amount of this retarding force increases very much as 
the velocity of the moving body increases ; hence in all 
experiments on this subject, the rate of travelling at 
which the friction is taken, should be particularly 
noticed, otherwise the experiment can be of no utility. 

F 2 



68 

A very good practical method of determining the fric- 
tion is to place a carriage, waggon, cart, or other 
vehicle mounted on wheels, and with axles well greased, 
upon a sloping road, and ascertain the inclination on 
which the vehicle will just move forward by the force 
of its own gravity. At this inclination, whatever it 
may be, the force of gravity is of course exactly equal 
to the friction, because the former is just capable of 
overcoming the latter resistance, and causing the body 
to move. The inclination at which this effect takes 
place is called the angle of repose, or the angle of 
friction. Now the force of gravity is easily deter- 
mined, being, as before stated, equal to the weight of 
the body multiplied by the inclination of the plane ; 
and the friction being, in the case supposed, exactly the 
same as the force of gravity, is of course determined 
by the same means. For example : if it be found that 
a carriage will just begin to move downwards on an 
inclination of 1 in 30, the friction of a ton weight on a 
level road of the same kind will be equal to 2240 x ^V 
= 74# lbs. The amount of friction thus found 



— 3 —'^^ 

ought to correspond with that which would be indicated 
by the dynamometer, because in both cases the rate of 
motion would be very slow. As the inclination of a 
road is usually expressed by a fraction of which the 
numerator is unity, this fraction being also called the 
natural sine of the angle of inclination, the rule for 
finding the force of gravity, by multiplying the weight 
by the fraction expressing the inclination of the plane, 
is of course the same thing as to divide the weight by 
the length of the plane corresponding to a rise of 1. 
Hence putting the weight = W, and the inclination of 
the plane = — , the simple formula — will express the 
force of gravity of the weight JV. This amount — has 



69 

to be added to the friction in the case of a weight 
being drawn up the phme, and deducted from it in the 
case of a weight descending the plane. Probably, how- 
ever, the most useful form in which to exhibit the effect 
of various inclinations with respect to the power of 
traction required, will be to determine the weights 
which, on a level road of the same kind, will require 
exactly the same power of traction. This is extremely 

simple: for if F be the friction of a given weight W, and 

w 

— as before be the force of gravity, we have the whole 

resisting force = i^ + — for the ascending plane, and 

F for the descending plane. Then to find the 

weight which the power F + — is capable of moving 

on a level plane, we have this proportion, F : W : -. 

F + — : W' the weight required, hence W + y^ = W'. 

In the same way for a descending plane, we have F : 

W : : F-^ : W; hence W -~= W, the weight 

which can be moved on a level with the same exertion 

of force as that required to move the weight W on 

a descending plane, whose inclination is — On this 

principle the following table has been constructed; but 

it must be observed, that the value of F, which in 

the table is assumed at 112 lbs., must be determined 

for any particular road on which the resistance has to 

be calculated. For roads where the friction eitlier very 

much exceeds or falls short of this amount, the last 

column only will be of use in saving the labour of 

calculation; because this shows the power required 

to overcome the force of gravity alone, independent 

of friction, on the several inclinations from 1 in 300 

up to 1 in 5. 



70 



Table of Resistances and Equivalent Loads, where the Friction 
is = — or 112 lbs. per Ton. 

20 ^ 



Rate of 
Inclination. 


Resistance of one ton, 

or power required to 

draw one ton when 

the friction is = — - 

or 112 lbs. per ton. 


Eciuivalent load on the 

level, or load which 

requires the same 

power of draught as 

one ton. 


Resistance 
arising from 
gravity alone, 
or value of 
the fraction 
2240 

r 




On the as- 
cending plane. 


On the de- 
scending plane 


On 


theascending 
plane. 


On the descending 
plane. 




lbs. 


Iba. 


Ton 


lbs. 


Ton. lbs. 


lbs. 


1 in 300 


119-47 


104 -53 




149-3 


0, 2090 


•7 


7 -4667 




, 295 


119 -59 


104 -41 




151 -9 


0, 2088 


-1 


7 -5932 




, 290 


119-72 


104 -28 




154 -5 


0. 2085 


-5 


7 -7241 




, 285 


119-86 


104 14 




157-2 


0. 2082 


-8 


7 -8596 




, 280 


120 -00 


104 -00 




160-0 


0. 2080 


•0 


8 -0000 




, 275 


120-15 


103-85 




162 -9 


0. 2077 


-1 


8 1454 




, 270 


120 -30 


103 -70 




165-9 


0, 2074 


•1 


8 -2963 




, 265 


120 -45 


103 -55 




169 


0. 2071 





8 -4528 




, 260 


120 -62 


103 -38 




172-3 


0. 2067 


•7 


8-6154 




, 255 


120 -78 


103 -22 




175-7 


0. 2064 


-3 


8 -7843 




, 250 


120 -96 


103 04 




179-2 


0. 2060 


8 


8 -9600 




, 245 


121 14 


102 -86 




182 -8 


0, 2057 


•2 


9 1428 




, 240 


121 -33 


102 -67 




186-7 0.2053 


3 


9 -3333 




, 235 


121 -53 


102 -47 




190 -6 0. 2049 


4 


9-5319 




, 230 


121 -74 


102 -26 




194-8 0.2045 


2 


9 -7391 




, 225 


121 -96 


102 04 




199-1 10,2040 


9 


9 -9555 




, 220 


122-18 


101 82 




203 -6 i 0. 2036 


4 


10-1818 




, 215 


122 -42 


101-58 




208 -4 


0.2031 


6 


10-4186 




, 210 


122 -67 


101 -33 




213-3 


0, 2026 


7 


10 -6667 




, 205 


122 -93 


101 -07 




218-5 


0. 2021 


5 


10 -9268 




, 200 


123 -20 


100-80 




224 -0 


0. 2016 





11-2000 




, 195 


123 -49 


100-51 




229 -7 


0. 2010 


-3 


11 -4872 




, 190 


123-79 


100-21 




235 -8 


0. 2004 


2 


11 -7895 




, 185 


124-11 


99-89 




24'2 -2 


0. 1997 


8 


12-1081 




, 180 


124 -44 


99-56 




248 -9 


0, 1991 


1 


12 -4444 




, 175 


124 -80 


99 -20 




256 


0, 1984 





12 -8000 




, 170 


125-18 


98 -82 




263 -5 


0. 1976 


5 


13-1765 




, 1()5 


125 -58 


98-42 




271 -5 


0, 1968 


5 


13-5758 




, 160 


126-00 


98-00 




280 -0 


0, 1960 





14 -0000 




, 155 


126 -45 


97 -55 




289 -0 


0, 1951 





14-4516 




, 150 


126 -93 


97 -07 




298 -7 


0,1941 


3 


14 -9333 




, 145 


127 -45 


96 -55 1 . 


309-0 


0. 1931 





15-4483 




, 140 


128 -00 


96 -00 1. 


320 -0 


0, 1920- 





16 -0000 




, 135 


128 -59 


95 -41 




331 -8 


0, 1908 - 


2 


16 -5926 




, 130 


129 -23 


94 -77 




3 14 •(> 


0. 1895 


4 


17-2308 




, 125 


129-92 


94 -08 




358 -4 


0. 1881- 


6 


17 -9200 




, 120 


130 •(!7 


93 -33 




373-3 


0.1866- 


7 


18 -(;()(J7 




, 115 


131 -48 


92 -52 




389 -6 


0. 1850- 


4 


19-4783 




, no 


132-36 


91 -61 




407 -3 


0. 1832 • 


7 


20 -3636 




, 105 


133 -33 


00-67 




4-26 -7 


0. 1813-3 j 


21 -3333 



71 



Table of Resistances and Equivalent Loads — continued. 



Rate of 
Inclination. 


Resistance of one ton, 

or power required to 

draw one ton when 

JfT 

the friction is = -53- 
or 112 lbs. per ton. 


Equivalent load on the 

level, or load which 

requires the same 

power of daught as 

one ton. 


Resistance 

arising from 

gravity alone, 

or value of 

the fraction 

2240 


On the as- 
cending plane. 


On the de- 
scending plane_ 


On the ascending 
plane. 


On the descending 
plane. 


r 




lbs. 


lbs. 


Ton. lbs. 


Ton. lbs. 


lbs. 


1 in 100 


134 -40 


89 


•60 


1. 448^0 


0. 1792 -0 


22 • 


4000 


,, 95 


135 -58 


88 


-42 


1. 471 6 


0. 1768 -4 


23 • 


5789 


,, 90 


136 -89 


87 


•11 


1. 497-8 


0. 1742 2 


24 • 


8889 


,, 85 


138 -35 


85 


•65 


1. 527 1 


0. 1712 -9 


26 


3529 


,, 80 


140 -00 


84 


•00 


1. 560^0 


0. 1680 -0 


28 • 


0000 


,, 75 


141 -87 


82 


•13 


1. 597 3 


0.1642-7 


29 


8667 


,, 70 


144 -00 


80 


•00 


1. 640 


0.1600-0 


32 


0000 


,, 65 


146 -46 


77 


•54 


1. 689-2 


0. 1550-8 


34 • 


4615 


,, 60 


149-33 


74 


•67 


1. 746 7 


0. 1493 -3 


37 


3333 


,, 55 


152 -73 


71 


•27 


1. 814 5 


0. 1425 •S 


40 


7273 


,, 50 


156 -80 


67 


•20 


1. 896 


0. 1344 


44 


8000 


, , 45 


161-78 


62 


•22 


1. 995 6 


0. 1244 4: 


49 


7778 


,, 40 


168 -00 


56 


•00 


1.1120 


0. 1 120 •O 


56 


0000 


,, 35 


176 -00 


48 


•00 


1. 1280^0 


0. 960-0 


64 


0000 


, , 30 


186 -67 


37 


•33 


1. 1493 3 


0. 746-7 


74 


6667 


,, 29 


189-24 


34 


•76 


1.1544 8 


0. 685^2 


77 


2414 


,, 28 


192 -00 


32 


•00 


1. 1600 -0 


0. 640 •© 


80 


0000 


,. 27 


194 -96 


29 


•04 


1. 1659 3 


0. 580-7 


82 


9630 


,, 26 


198 15 


25 


•85 


1. 17-23 1 


0. 516-9 


86 


1538 


,, 25 


201 -60 


22 


•40 


1. 1792 


0. 448 -0 


89 


6000 


,, 24 


205 -33 


18 


•67 


1.1866^7 


0. 373 3 


93 


3333 


,, 23 


209 -39 


14 


•61 


1. 1947 8 


0. 292 2 


97 


3913 


,, 22 


213 -82 


10 


•18 


1. 2036 -4 


0. 203 •O 


101 


8182 


,, 21 


218-67 


5-33 


1. 2133 -3 


0. 106-7 


106 


6667 


,, 20 


2-24 -00 





2. 000-0 





112 


0000 


,, 19 


229 -89 






2. 117-9 






117 


8947 


,, 18 


236 -44 






2. 248-9 






1-24 


4444 


,, 17 


243 -76 






2. 395 3 






131 


7647 


,, 16 


252 -00 






2. 560-0 






140 


0000 


,, 15 


261 -33 






2. 746-7 






149 


3333 


,, 14 


272 -00 






2. 960-0 






160 


-0000 


,, 13 


'284 -31 






2.1 206^2 






172 


3077 


,, 12 


298 -67 






2. 1493 -3 






186 


6667 


,, 11 


315 -64 






2. 1832 -7 






203 


•6364 


,, 10 


336 -00 






3. 000-0 






224 


•0000 


,, 9 


360 -89 






3. 491-8 






248 


•8889 


,, 8 


392 -00 






3. 1120 






280 


•0000 


,, 7 


432 -00 






3. 1920 -0 






320 


-0000 


,, 6 


485 -33 






4. 746-7 






373 


-3333 


,, 5 


560 -00 






5. 000-0 






448 •OOOO 



72 

The construction and use of this table are so simple 
as to require very little explanation. The 2nd and 3rd 
columns show the actual amount of power required to 
drag- a weight of one ton, on the several ascending and 
descending planes, of which the inclinations are given 
in the 1st column. These amounts of power being 
known, the 4th and 5th columns, showing the load 
which can be drawn on a level, by the same power as 
that necessary to draw a ton respectively up and down 
the several inclinations in the 1st column, are easily 
calculated by means of the proportion already men- 
tioned. Where the load has to be drawn up the in- 
clination, it is evident that more power must be exerted 
than is necessary to draw the same load on a level; 
hence the amounts of power in the 2nd column are all 
more than 112 lbs., because this is the power required to 
draw a ton on the level. Again, where the load is 
descending the inclination, a less amount of power is 
necessary than on a level ; hence the amounts in the 3rd 
column are all less than 112 lbs. It follows also, from 
the nature of the formula FT— , by which these amounts 
have been calculated, that on any given inclination the 
amount of power required to ascend, the amount re- 
quired on a level, and the amount required to descend 
the given inclination, are three quantities having a 
common dilVerence, and therefore in arithmetical pro- 
gression. This is further evident, in considering that 
the excess required to ascend is equal to the diminished 
quantity sufficient in descending. And since the equi- 
valent loads which can be drawn on a level are 
proportional to the power expended, the same property 
obtains with regard to tliem : — for example, the load 
which can be drawn on a level with the same power 
recjuired to draw a ton weight up any given inclination, 
and the load which can be drawn on a level with the 
same power required to draw the ton weight down the 



73 

given inclination, are the extremes of an arithmetical 
progression, of which one ton is the mean or middle 
term. These properties may be shortly expressed alge- 
braically: thus, let P be the power required to draw 
the load TFup any given inclination, and p the power 
to draw the same load down the inclination ; also, let 
F, as before, be the friction of the load W on &. \e\e\, 
then we have -^— = F. Further, let L be the equiva- 
lent load on a level for an ascending plane, and / the 
equivalent load for a descending plane of the same incli- 
nation, then - — = W. 

rt is obvious, if we know by experiment the amounts 
of power P and p required to draw any weight respect- 
ively up and down any inclination, that we can at once 
determine the friction of that weight, or the power re- 
quired to draw it on a level, and also the rate of inclina- 
tion for which the amounts Pandphavebeen ascertained. 
Without supposing that this method of finding the in- 
clinations of a road, will ever supersede the more accu- 
rate method of levelling for that purpose, it may yet 
often be found useful to approximate in this way. We 
have already seen that — ^ ~ ^ > ^^^^ since P is the 
whole power of draught up the plane, and F is that 
part of the whole power which arises from friction, it is 
evident that P — F is equal to the resistance arising 
from the force of gravity on the inclination. Now 
the force of gravity is also equal to — ; hence putting 
these two expressions equal to each other, we have only 
to find from the equation P — P = — , in which all the 
quantities are given except r, the value of this unknown 
quantity expressing the inclination of the plane. Solv- 
ing then the above equation, we have r(P — F) = W, 
and ^ _p =r, the rate of inclination. An example of 
this may be taken from the table: — Suppose the amounts 
of power required to draw a ton weight up and down a 



74 

certain inclination be respectively 128 and 9l> lbs. then 
— - — = -^ = 112 = F the friction as in the table. 
And rii^ = ^fi^ = 140 = r; that is, the inclination 
of the plane for which these amounts of power have been 
determined, is 1 in 140, as in the table. It is easy when 
the inclination of a plane is given to ascertain the dif- 
ference of level between any two points on its surface, 
provided we know the direct distance between them 
measured in the line of the plane : thus, if an inclination 
rise 1 in r, it is evident that in each unit of length the 
rise will be — ; hence if we divide any given length on 
the plane by the denominator of the fraction expressing 
the rate of inclination, the quotient will be the difference 
of level of the two points at the extremities of that 
length. 

In all roads there is a certain angle of inclination 
on which it will require no power to cause a weight to 
descend. This has been already mentioned under the 
name of the angle of friction ; and it follows from the 
nature of the relation existing on every plane, between 
the power required to descend and that required to 
ascend, that where the power to descend is equal to 
zero, or where p =0, the power required to ascend is 
equal to 2 F or double the friction. But where the 
value of jtj becomes negative or less than nothing, that 
is, where — is greater than F, the amount of power re- 
quired on the descent being also less than nothing, has 
no longer to be calculated. In fact, where the plane is 
of greater inclination than the angle of friction, the load 
in descending acquires an accelerating force, which if 
not checked would urge it downwards too rapidly. 
Hence it is usual in such a case to increase the amount 
of retarding force actually occasioned by friction, and 
for this purpose the break or skid is applied — the in- 
clination at which it becomes necessary to use the 



75 

break, or in other words to lock the wheel, being pro- 
perly speaking the angle of friction. It is obvious that 
this angle is not the same for all kinds of road, since it 
depends entirely on the amount of the friction itself; thus 
in the table where the friction of one ton is taken at ^V? 
or 112 lbs., the angle of friction is that which is made 
with the horizon by a plane whose inclination is 1 in 20 ; 
and in general terms, if F be the amount of friction for 
any weight W, the inclination of the plane forming the 
angleof friction, will be — . 

In order to illustrate the effect of steep inclinations, 
it may be useful again to refer to the preceding table, 
where we find for instance that the load on a level, equi- 
valent to one ton ascending an inclination of 1 in 20, 
is just double or two tons ; and if the road become as 
steep as 1 in 10, the equivalent load is three times as 
great or three tons ; thus, the inclination of 1 in 10 re- 
quires 50 per cent, more power than the inclination of 
1 in 20. Again, the inclination of 1 in 60 requires a 
power equivalent to that which would draw 1 ton 747 lbs. 
on a level ; and as this equivalent load bears the same 
proportion to two tons as this latter load bears to 
three tons, it is evident that the inclination of 1 in 10 
has the same relation to 1 in 20 as this latter has to 
1 in 60. Next, as to the actual differences of draught, 
it appears, that if a horse can just draw one ton upon a 
level road, it will require two horses to ascend with this 
weight an inclination of 1 in 20, and three horses to 
ascend an inclination of 1 in 10. Hence the extremes 
of power required, within the short range of 1 in 10 and 
1 in 20, present as wide a difference as in the long range 
between 1 in 10 and a perfectly horizontal plane. 

When it is necessary to calculate the draught re- 
quired on a road where the friction has been deter- 
mined at any other amount than 112 lbs., the 6th or 



76 

last column of the table must be employed. Thus, if 
the friction on a road should be found, for example, to 
be 150 lbs. per ton, and it be necessary to find the power 
of draught required on an inclination of 1 in 80 : — Take 
from the table the amount in the (ith column opposite 
to 1 in 80, this amount which is 28 lbs. being- the force of 
gravity alone. Then 150 + 28 = 178 lbs. is the whole 
power required to draw a ton up the inclination, and 
150 — 28 = ] 22 lbs. is the amount required to draw the 
weight down the inclination. Further. ??12_iL_iii-= 

° * 150 

2658 lbs. the weight which can be drawn on a level by 
the power of 178 lbs., and '^'^^^^^ ^^^ =1 822 lbs. the weight 
which can be drawn on a level by the power of 122 lbs. 
The 6th column of the table will also be useful if we 
wish to ascertain the angle of friction corresponding to 
difi'erent amounts of draught on roads. For example, 
if on any road the friction or resistance on a level be 
equ^l to 80 lbs. per ton, the angle of friction for this road 
will be 1 in 28. And so of any other amounts in the 6th 
column, the rates of inclination opposite to them in the 
first column being respectively the numbers which ex- 
press the corresponding angles of friction. 

In the preceding exposition of the methods of esti- 
mating the forces of friction and gravity on different 
roads, it must be understood that these forces express 
only the power required to set in motion a given weight 
under the circumstances for which that power is cal- 
culated. In order to know the whole power required 
to draw a given weight along any length of plane, 
inclined or horizontal, we must multiply the force re- 
quired to move it by the length of the plane itself, and 
the product will l)e the whole power required. This 
must be evident if we consider that the force required 
to set in motion any load placed on a certain plane, is 
that weight which hanging over a pulley will just cause 



77 

the load to move ; and if we conceive the load to ad- 
vance on the plane any given length, this advance must 
be produced by a corresponding and equal descent of 
the attached weight. Hence, if a power P be required 
to move a given load on a plane 500 feet long, the whole 
force required to move the load from one end of the 
plane to the other is = 500 P; that is, the force is equal 
to the weight P raised 500 feet high, or which is the 
same thing, to the weight 500 P raised 1 foot high. 

In applying the principles which have now been 
laid down, to determine the comparative merits of two 
or more lines of road, it will be necessary to compute 
for each inclination the actual power required to ascend 
and descend with a given weight, and it would seem at 
first sight, that the aggregate or total of these amounts 
would afibrd an expression by which to indicate the 
comparative merit of any line of road. It will be found, 
however, in following out the consequences of some of 
the propositions laid down in the preceding pages, that 
this expression, although perfectly accurate, as contain- 
ing the actual amounts of force to be exerted on each 
plane throughout the road, will yet fail in a remarkable 
degree to establish the absolute superiority of one line 
over another, although the power on the former may be 
unquestionably less in amount than that required on 
the latter. In illustration of this exception, it will be 
necessary to revert to that relation subsisting between 
the three amounts of power exerted in ascending any 
given plane, in moving on a level, and in descending the 
given plane. It has already been observed, that these 
three quantities are in arithmetical progression, and the 
expression already made use of, namely, — ^-^ = F, 
exhibits the following result; that the half sum of the 
amounts of power required to ascend and descend a 
given inclination, is exactly equal to the power required 



78 

to move over a level plane equal in length to the in- 
clination itself. The same proposition may also be 
expressed in other words, thus: — that to ascend and 
descend a given inclination, requires the same power as to 
travel backwards and forwards over a level plane equal 
in length to the inclination. 

Before proceeding to the consequences of this doc- 
trine it is necessary to notice, that it no longer holds 
true when the angle of inclination of the giveli plane 
exceeds the angle of friction for the road in question. 
It is evident that on all planes where the carriages will 
descend by the force of their own gravity, the expression 
above used is no longer correct ; because, whatever be 
the inclination of the plane the only value of j? is ; 
and as P increases with each increase in the rate of 
inclination, it will at once be obvious, that to ascend and 
descend any plane forming with the horizon a greater 
angle than the angle of friction, requires more power 
than to travel backward and forward the same distance 
on a level plane. It will therefore be understood, with 
respect to the proposition establishing that an equal 
amount of power is required to travel up and down 
an inclination, and to travel double the length of the 
inclination on a level, that this applies only to planes 
of less inclination than that formed by the angle of 
friction. 

We are now to consider the extent to which an 
expression of power leading to such a result, may be 
used as a means of comparing the merits of different 
roads. With this view we are to bear in mind the 
nature of the power which has to be employed, in over- 
coming the several resistances that may be determined 
by calculation. This power on the common roads is 
generally confined to the labour of horses; and when, 
with reference to this species of power, we assert the 



f9 

proposition as to the equality of force required, it be- 
comes perhaps more irreconcileable with the knowledge 
derived from every-day experience, than when applied 
to any other description of power whatever. Thus, to 
assert that the labour of travelling along a mile of road 
on which is a summit 100 feet high requires no more 
power than to travel over a mile of level road, appears 
very inconsistent with generally received opinions ; and 
yet this assertion is strictly in accordance with the 
general proposition ; because, if the summit be placed 
half way the inclination on each side will be 1 in 26, 
which for an amount of friction = -^^-^ is a flatter inclina- 
tion than the angle of friction. It will therefore be 
necessary to introduce into the expression for the actual 
mechanical force to be exerted, some modifications, in 
order to render the results more nearly coincident with 
those of known experience. In the first place, the horse 
ascending an inclination has to raise his own weight in 
addition to the load, and the power thus expended must 
of course be added to that necessary for the load. 
Again, in descending, it is probable that it requires just 
as much exertion to transport his weight as on a level. 
Now the additional power required to carry the weight 
of a horse up an inclination, is evidently equal to his 
whole weight multiplied by the height of the inclina- 
tion; and in fact, the power required for this purpose is 
in no respect different except in amount from that re- 
quired to raise the load drawn by the horse. Hence, it 
will be proper in determining the resistance of a load 
to be drawn up any inclination, to consider the 
weight of the horse itself as a part of the load. This, 
if we assume the weight of a horse at lOcwt., or half a 
ton, and suppose the load to be drawn is one ton, the 
amounts expressing in the table the resistances arising 
from gravity must be increased 50 per cent, for the 



80 

upward draught. The other modifications which it might 
be proper to introduce, are those arising from the dis- 
advantageous way in which the muscular power of a 
horse is exerted, both in ascending and descending 
inclined planes. The actual effect of this drawback in 
diminishing the performance of horses, is a subject of 
which the elucidation depends entirely on experiment. 
We have seen in the preceding pages, that the mecha- 
nical power required to draw any given weight, first up 
an inclination and then down again, is precisely the 
same as that required to draw the weight to and fro 
on a level of equal length with the inclined plane. We 
may be certain, therefore, that if a steam-engine, or any 
other machine, were erected at the top of a sloping 
plane, in order to draw the load up and down the plane, 
the power expended would be precisely the same as on 
a level. We are not however to suppose, that it would 
be found so advantageous even to employ machinery to 
work an inclined plane in this way as it would be to 
work on a level by the same means ; yet we know per- 
fectly well that in either way the same mechanical 
power is expended. But on the other hand experience 
very plainly teaches, that a horse cannot, with the same 
ease or with only the same exertion of force, draw a 
load first up and then down any inclination whatever, as 
he could on a level of the same length. One reason why 
a greater exertion is required on the sloping plane we 
have already assigned — namely, because his own weight 
has then to be raised as well as the load ; but it is also 
certain that there are some other considerations con- 
nected with the physical structure of the horse, which 
increase yet more the exertion required on sloping 
planes. Here then is the necessity for experiment: — 
It is required to know what is the cfl'ective performance 
of a horse on dillercnt inclinations, as compared with 



81 

that on a level. The determination of this problem 
certainly presents some difficulty, and yet in no other 
way can we strictly pronounce on the merit of a road 
with reference to the actual kind of power which is to 
be used upon it. 

The mechanical expression for the amount of power 
required, will enable any one to judge to a much greater 
extent on this subject than he could in the absence of 
any investigation. For example: if we know that a 
road has an inclination of 1 in 28 for the length of a 
mile, and that it then descends by an inclination on the 
other side, it will appear from the table that during 
this mile the horse must draw with a force capable of 
drawing 1 ton 1600 lbs. on a level — and adding to this 
50 per cent, on the amount of gravity alone, for the 
increased power required to raise the horse itself, the 
whole force exerted will be capable of drawing on a 
level 1 ton 1600 lbs. + 800 = 2 tons 1601bs. Now, ad- 
mitting that in descending the plane after having passed 
over the summit, the force of draught required will be 
something less than that which is necessary on a level, 
yet the balance is so decidedly in favour of a level road, 
that no one could hesitate in pronouncing a decision 
to that effect. 



82 



CHAPTER VIII. 

On the Method of Estimating the Prices of Earth- work, 
and other kinds of Labour necessary in the Improve- 
ment and Repair of Roads. 

The particular circumstances of different localities 
exercise so much influence on the value of most 
descriptions of labour and materials necessary in road- 
making, that any thing like a general scale, comprising 
all kinds of labour, would be entirely out of the ques- 
tion, and probably quite inapplicable to every other 
than the particular district from which the data for its 
construction had been derived. This remark applies 
to the prices of digging, screening, breaking, washing, 
and otherwise preparing gravel ; the prices of quarry- 
ing and carting stone, and forming the pitching in the 
bed of the road; also to the prices of fencing and 
ditching, constructing drains, footpaths, &c. All these 
kinds of labour vary in value, and the price to be paid 
for them, according to the condition of the labouring 
population, and their usual employers the farmers, and 
according to other circumstances which it will not be 
necessary here to enter upon. 

In the improvement of roads upon an extensive 
scale, however, the preceding kinds of labour are all 
of minor importance as compared with that of exca- 
vating earth and filling" it into embankments, in order, 
by thus lowering the hills and raising the valleys, to 
produce more gradual inclinations, and consequently 
a better kind of road. The value of this description 
of work (although, as may naturally be supposed, it 



83 

forms a study of the greatest consequence to all those 
engaged in the management of roads,) is generally very 
little understood ; and many and serious are the evils 
which have fallen upon the heads of trustees and sur- 
veyors from the want of practical knowledge on this 
subject. The obvious data from which the value of 
excavating earth should be computed, consist of the 
amount or quantity of the material which can be ex- 
cavated by a given quantity of labour ; and thus, if the 
value of this labour be known, we obtain at once the 
price of the work done, and may estimate from such 
groundwork the value of any other quantity, great or 
small. 

These data of course can only be derived, in the 
first instance, from actual practical observation and 
experience on many and different works; but being 
once known, they become of great importance in the 
business of estimating the future cost of any works of 
the same kind. 

The workmen employed in earth excavations are 
always divided into two classes, getters and fillers ; 
the former employed in undermining, driving down 
by piles, and breaking to pieces with pickaxes the 
earth to be loaded into the carts or barrows by the 
fillers. It will be seen, in the course of the following 
observations, that in determining the price of earth- 
work, it is very important to obtain an accurate know- 
ledge of the proportion in which these two classes, 
getters and fillers, are required to be employed. 

Where any considerable quantity of earth has to 
be removed, the modern practice is to lay down iron 
rails for the waggons to travel on from the excavation 
to the embankment. It is found in such cases to be 
the interest of the contractor, that the roads from the 
excavation to the teaming-places should be constructed 

G 2 



84 

in a very perfect manner, and that heavy waggons of 
the most durable make should be employed. We may 
readily conceive the extensive establishment of roads 
and waggons necessary in some of the gigantic works 
of the great lines of railway, on which it is by no 
means uncommon to meet with single hills to be 
lowered and filled into a valley containing upwards of 
a million of cubic yards, with a distance of carriage 
varying from one to five miles. In the transport of 
such vast masses of earth for such considerable dis- 
tances, the roads cannot be too well constructed ; and 
in the end it will generally be found that capital ex- 
pended in this way produces a very satisfactory return. 

A wide diflference exists, however, between the vast 
earth-works of the railways and those which are usually 
necessary in road formations, where the quantity of 
earth to be excavated from any one place seldom 
exceeds four or five thousand yards, and scarcely ever 
amounts to twenty thousand. In works of a nature 
comparatively so trifling, the expense of heavy waggons, 
and the rails and sleepers necessary to carry them, 
would on no account be justified. 

I shall therefore confine myself to those methods of 
removing earth which are more particularly adapted 
for small quantities and short distances. Of all the 
implements employed for this purpose, the com mon 
earth wheelbarrow is perhaps the most convenient, not 
only from the ease with which it can be loaded, but 
from the great facility with which it can be brought to 
the very spot where it has to be filled or emptied. By 
simply turning the direction of the spurring, which is 
generally a 10 or 14 feet plank, without altering the 
direction of the main line of wheeling planks, the 
barrows can be filled at the face of the cutting, or 
emptied at tlie teaming-place at the precise spot re- 



85 

quired. But with waggons and rails tiie case is very 
different; for any alteration at either end of the road 
requires generally a considerable length of rails to be 
taken up and replaced, an operation which is found 
very tedious and troublesome, and which contributes 
very much to increase the expense of the teaming. 
Where waggons are employed, this part of the work 
seldom costs less than Id. per cube yard; and in 
winter and wet weather, I have frequently known the 
teaming of adhesive clays, and some descriptions of 
wet sand, to cost from three-halfpence to twopence per 
cube yard. 

The advantage of filling into barrows instead of 
waggons I estimate, from practical experience, to be 
equal to the removal of the earth, after filling it, to a 
distance of one stage of wheeling; or in other words, 
the same set of fillers in the same material will fill and 
move with barrows, to a distance of one stage, for the 
same price that they can fill alone into the waggons. 
This arises from the extra lift the workman must make 
to raise his load over the side of the waggon : and not 
only is it necessary in this way to carry it upwards a 
much greater distance, but the moment the workman 
raises himself to a perpendicular position, he works to 
great disadvantage ; for it requires much more strength 
to raise the same weight when he once elevates his 
position, than whilst he remained in a leaning or stoop- 
ing attitude. In the latter position the weight of his 
body powerfully assists in bringing up the load, but in 
the upright posture he has nothing to assist him but 
his arms. In filling into a waggon also, the constant 
strain upon his loins is so excessive, that he cannot 
take up at any one time, and deposit in one of the high 
waggons, more than two-thirds of the load that he 
could raise and fill with ease into a barrow. It would 
seem that these causes very satisfactorily account for 



II 



8G 

the difference already mentioned between the two kinds 
of filling. The quantity of earth, however, which the 
barrow is capable of holding being very small, it is 
obvious that this mode of removal would become 
tedious and expensive for long distances; and it is 
found accordingly, that the barrow cannot be econo- 
mically employed in the removal of earth which has to 
be taken more than sixty yards from the face of the 
cutting. A stage of running with barrows is twenty 
yards, and the price per stage Id. per yard : it is how- 
ever usual for the principal contractor to bargain with 
his gangsman or foreman at a price per yard, for any 
distance not exceeding twenty yards from the face of 
the cutting, and at the rate of Id. per yard extra for 
every stage of twenty yards beyond the first stage ; thus 
stuff requiring one getter to three fillers would cost 
6d. per yard. It must be here observed, that one man 
can wheel to the distance of twenty yards for three 
fillers, or from forty to fifty yards per day ; thus the 
cost of Gd. per yard is incurred, filling Sd., getting Id., 
wheeling two extra stages 2d. At this rate of pay six 
men will remove about forty-two yards, and earn for 
their labour 3s. 6d. per day ; each filler filling fourteen 
yards, and removing it from the face to the distance, 
as it increases, from one to twenty yards. 

With reference to the best description of cart or 
waggon to be employed, when it becomes necessary to 
abandon the use of the barrow, there are of course as 
many diflerent opinions as there are varieties of form 
and figure in the vehicles themselves. I have myself 
devoted much attention to this subject, and having 
used many different kinds, am enabled to point out 
one or two which possess nearly equal advantages in 
point of convenience and economy. One of the best 
with which 1 am acquainted is the three-wheeled 
cart. These can be taken in and out of the cutting. 



87 

either backwards or forwards : they stand low, and 
are therefore easily loaded, and have a decided ad- 
vantage over the common two-wheeled cart, and the 
Scotch one-horse cope-cart, on account of the ease 
and expedition with which they can be dispatched from 
the face of the cutting and from the teaming-place. 

A great deal of time is always lost with the common 
two-wheeled carts, because the horse must wait during 
the process of loading and unloading; but with the 
three- wheeled cart the horse draws with chains, which 
are hooked on to the loaded waggon, which, on coming 
to the face of the cutting, is not detained there a mo- 
ment longer than is occupied by this operation : and the 
same thing takes place at the teaming-head, where the 
horse, as soon as he arrives with a loaded cart, is hooked 
on to the one which he had left there the last trip, and 
returns as quickly as he can to the face of the cutting. 
In this way the three-wheeled carts work remarkably 
well, and with great regularity, particularly in fine 
weather, and good dry shifting earth. Although in wet 
weather, and with clayey earth to remove, they cannot 
be so strongly recommended, yet there are so many 
times and places where these carts can be employed to 
advantage, that they ought, if possible, in all earth- 
works to be in readiness for the occasion which may 
call them into use. In forming embankments, where 
it is important that rapid consolidation should take 
place, the three-wheeled carts are extremely valuable, 
because they can be teamed over a two feet face almost 
as conveniently as over a heavier and deeper lift ; and 
the embankment may thus be formed in shallow layers, 
over which the constant travelling of the horses and 
carts produces the effect of consolidation, almost simul- 
taneously with the completion of the embankment. 

Earth which has been filled in this way is also more 
likely to stand firm, and much less liable to slips than 



88 

that which has been placed in embankment in a less 
compressed state. Three-wheeled carts may be econo- 
mically used in removing earth to a distance of about 
half a mile, or say 900 yards; and the cost of carriage 
may be taken at about ] d. for every 100 yards, where 
the distance of removal is about 300 yards. 

I have observed that a good horse will make from 
forty-five to fifty journeys per day, drawing on an 
average 18 cube feet at a time ; or in other words, a 
good horse will remove from 30 to 33 cube yards per 
day to a distance of 300 yards from the face to the 
teaming, or unloading end : where, however, the length 
of carriage exceeds this distance, and the loading 
and unloading become less frequent, the expense of 
carriage will be proportionably diminished. In the 
same ratio also the cost will be augmented for shorter 
distances than 300 yards, where of course the interrup- 
tions of loading and unloading are more frequent. 

Another description of cart which I have exten- 
sively employed in removing small hills, has been found 
very convenient both for loading and teaming. This 
is termed a go-cart, and has sometimes been run by 
men upon planks; but as they are very apt to get off 
the tracks, and destroy the planks in an extraordinary 
manner, I do not recommend their use in this way. 
The go-cart has two long trams or shafts, to the end 
of which the horse may be hooked, and is supported by 
tvvo legs in front, which preserve the cart when at rest 
in a horizontal position. When the cart is in motion, 
the driver travels between the shafts, holding them up 
to clear the legs from touching the ground, and prevent 
the cart from tipping over, as it would be likely to do 
with only one point of support. 

I prel'er these carts made large and very strong, 
with substantial wheels : they will carry on a good 
road from 18 to 23 cube feet of earth, and with this 



89 

load the horse will travel at a fair speed. These 
carts possess all the requisites of the three-wheeled 
kind, both in the facility with which they can be 
loaded and unloaded without detention of the horse, 
and in their capability of being teamed in shallow lifts. 
In some other respects the go-carts are superior to the 
former kind, particularly on soft or new made roads, 
where they can be drawn with more ease than the 
three-wheeled cart, in which the third wheel adds con- 
siderably to the horse's draught. On the other hand, 
the go-carts are not so easily managed as the three- 
wheeled contrivance, which may very safely be en- 
trusted to a boy; but the go-cart requires a man, or 
at all events a strong and active youth, to hold up the 
shafts and manage the horse, which is travelling before 
him. Of all the carts I have tried for the removal of 
earth to short distances, I never found any to equal in 
convenience a small go-cart of light construction, 
contrived and used by myself on the Union Canal, in 
Scotland. These carts, of which a drawing and de- 
scription are given in the recent celebrated publication 
by Mr. Weale, of the " Engineering Works of Great 
Britain," contained each about 18 cube feet of earth, 
and were run by men with great ease on light rails,* 
laid down on longitudinal bearing planks, 10 inches 
wide, 3 inches thick, supported on wooden sleepers. 
The tail-board ;s hung by hinges, and is disengaged 
and shut again by the man at the teaming-place, with- 

* It may be necessary to explain that tlie rails here mentioned bore no 
resemblance to those used in railroads of the present day. They were simply 
flat bars of iron, fixed upon the bearing planks by nails and straps. To 
modern contractors cngag:ed in large earthworks I should recommend the 
rail adopted by Mr. Gibbs, on the London and Croydon Railway, as being 
decidedly superior to every other with which I am acquainted. This rail was 
designed by Mr. Gibbs entirely to dispense with the use of chairs, and is 
accordingly fastened to the longitudinal bearers by screws passing through the 
broad base of the rail. Great solidity is thus secured, and the rail at the 
same time possesses the recommendation of being lighter, and more econo- 
mical than any other hitherto adopted. 



90 

out quitting his station at the shafts : thus not only is 
much time saved in teaming, but the expense of it is 
also avoided. 

Having determined, according to the particular 
circumstances of the case, the kind of waggon or cart 
to be employed in removing the earth from the cuttings 
to the embankments on the intended road, the atten- 
tion of the engineer or surveyor must be directed to a 
still more important part in the business of estimating; 
namely, the precise nature of the earth with which the 
works are to be constructed. 

It must be obvious, that the general name of the 
earth, such as clay, sand, gravel, or chalk, affords by 
no means a correct criterion by which to judge of its 
real nature ; because all of these, and more particularly 
the clays, contain amongst themselves many shades of 
difference in respect of hardness and tenacity. The 
extent to which any particular earth is characterized 
by one or both of these qualities, determines the nature 
of the material in question ; because they indicate the 
ease or the difficulty with which the earth can be broken 
up, and otherwise separated from the general mass, into 
pieces of suitable size for loading into carts. 

The faculty of being able to pronounce correctly on 
the nature of the earth to be removed, can only be 
acquired from a long course of practice, which shall 
have afforded opportunities of witnessing the execution 
of earth-work in every different variety of circumstance 
and position. Such a course of practice can alone 
furnish the original data already mentioned, from 
which to determine the amount of labour required in 
the removal of different descriptions of earth. This 
of course is the same thing as to be able accurately to 
judge its precise nature, because upon this depends 
the extent of labour necessary to produce a certain 
effect. It is by no means sufficient to determine these 



91 

data, as some have attempted to do, from the single 
isolated observation of one piece of work managed in 
a particular manner, which may be judicious or other- 
wise, according to circumstances. Nothing in fact is 
more common than to see the execution of earth-work, 
under the management of ignorant contractors and 
inexperienced gangsmen, costing from one-third to 
one-half more than it would under proper and judicious 
arrangements. 

This may arise from the awkwardness and incom- 
petency of the workmen, even when well provided with 
implements ; and in many other cases, from the insuffi- 
cient supply of working implements and horses, the 
want of good roads, and other requisites of the same 
kind. The difficulties occasioned by a narrow and 
confined system of management, adopted usually under 
a false impression of economy, will invariably produce, 
in the very best men, an eff'ect so dispiriting that they 
cannot do more than half or two-thirds of the work, 
which a proper system of management would render 
them capable of performing. 

By means of the practical experience to which I 
have alluded, and which cannot be otherwise acquired 
than from extensive observations on the progress of 
earth cuttings, the student will be able, on viewing the 
face of an open cutting, to determine how many yards 
per day of the earth, which the cutting exhibits, a good 
workman can fill into the vehicle intended for its re- 
moval. From the same experience also he will be 
able to judge upon another point of no less importance, 
namely, the extent of preparation which the earth must 
undergo in the way of breaking up, before it becomes 
ready for the fillers. The proportion of getters neces- 
sary to supply and keep constantly employed a given 
number of fillers being thus known, the data for valuing 
the price of any earth excavation are at once in pos- 



92 

session of the engineer. He may now with confidence, 
after inspecting the trial pits and casual openings which 
are to be fonnd in the neighbourhood of most public 
works, classify the various kinds of earth according to 
their several qualities, and determine for each the 
prices on which his estimates are to be framed. 

If we consider, however, the extent of practical 
experience, and the variety of observation necessary to 
qualify an engineer thus to judge of the value of earth 
excavation, we shall be at no loss to account for the 
eternal difference of opinion amongst engineers in all 
that relates to the prices of the works under their con- 
trol : nor for the same reason is there any thing at all 
surprising in the constant recurrence, session after ses- 
sion, of the extremely conflicting evidence brought 
before Parliament on the subject of estimates for public 
works. A great error into which students are apt to 
fall when attempting to acquire for themselves a know- 
ledge of prices, arises from the supposition that they 
can, by observing personally the progress of one or 
two earth-works under their inspection, and by com- 
paring the daily progress with the quantity of labour 
expended in the execution, arrive at the real cost of 
similar works in other situations. Nothing can be more 
erroneous than this ; for such a course of observation 
does not even furnish data sufficient to determine the 
cost of the particular works which have been the sub- 
ject of observation, much less of other works which 
may be considered analogous to those originally ob- 
served. In order to explain this, it must be remem- 
bered, that there are many circumstances in all earth 
excavations which occur to occasion expense to the 
principal contractor, and with which the gangsmen have 
nothing to do> Thus these circumstances, although 
most important as influencing very materially the price 
of the work, could never be known to the most scruti- 



93 

nizing iuspector or tiine-kceper, unless instructed by the 
contractor himself. The execution of the work may be 
attended also by other circumstances, of which the 
young engineer may observe the existence without 
being able to estimate their eifFect on the price of the 
work. For example : a continuance of unfavourable 
weather may occasion a dreadful increase of outlay in 
the formation of proper roads to carry the excavated 
earth, in addition to extraordinary wear and tear of 
the working implements, and the destruction of horses, 
carts, and gear of every descrijjtion. Sometimes the 
sliding and giving way of embankments, and accidents 
of the same kind in the cuttings, and sometimes the 
necessity for unexpected drainage to keep the work 
dry during its progress, will contribute very heavily to 
increase the price of the work beyond what might 
appear to a casual observer to be the cost of its 
execution. 

One grand cause, however, I have not yet men- 
tioned, although it ranks in imjjortance before all the 
others, and this is the practice of forcing the works, 
with the view of completing them within less than a 
fair and reasonable time for their performance. This 
practice, which is not only most destructive to a con- 
tractor's interest, but more conducive than any other to 
the extravagant cost of many great public works, is 
not unfrequently persisted in during the worst seasons 
of the year, and this to such an extent as to render it 
necessary to carry on the work night and day through- 
out the year. 

It would be no difficult task to enumerate many 
other circumstances which would render the cost of 
any particular work very different, according as these 
happened to be favourable, or otherwise. It is pro- 
bable, however, that enough has been already said to 



94 

show, that the capacity of justly appreciating the in- 
fluence of these circumstances in varying the price of 
earth-work, is confined almost entirely to the expe- 
rienced contractor, who, during a long- and intimate 
acquaintance with the subject, has drawn his experi- 
ence from the actual profit or loss he has himself sus- 
tained under like circumstances. 

The preceding observations, on the difiiculty of cor- 
rectly estimating the prices of earth-work, are by no 
means intended to deter the unpractised engineer or 
surveyor from attempting to form an estimate of its 
cost. They are simply designed to show the fallacy of 
assuming any fixed prices as applicable to all work of 
the same kind in every situation ; and if they suggest 
to the younger members of the profession the necessity 
of proceeding on more minute and particular data than 
those usually taken, the intention which has given rise 
to them will be fully accomplished. With this expla- 
nation, I proceed to the details which have been 
already alluded to, as calculated to simplify the 
general business of estimating earth- work. 

The various strata which are found in excavations 
made for roads, railways, and canals, may be classed 
under the following heads : 

1st. Underhanded soft earths, such as peat, soft marl, 
ouze, sand, gravel, common mould, and some of the 
softer clays. 

2nd. Grafting earths, comprising the first layer, or 
one draw in depth of any tenacious earth ; also all clays 
requiring the use of a foot-iron to force the grafting 
tool into the earth, which can be more readily dis- 
placed and filled in this way than by the method of 
falling it into the cutting. 

3rd. The earths which require getting, of which kind 
are all the hard clays, hard gravel, chalk, common 



95 

rocks of every description, and in fact every variety 
of earth which cannot be filled either by the common 
shovel or grafthig tool alone, but requires, by some 
means or other, to be forced to the bottom of the 
cutting, and broken to pieces. 

In judging the cost of excavating any of these earths, 
there are two things to be observed, namely, the quan- 
tity which can be filled by a given amount of labour, 
and the number of getters necessary to keep that same 
amount of labour in operation. 

The first class of earths described above, namely, 
the underhanded stuff, is filled into carts, or thrown to 
a distance by the workman standing on the lower level 
of the earth which he has to remove, and taking up 
the material on his tool without any other exertion 
than that of raising each spade or shovel-full, and 
either placing it in a cart, or throwing it to a distance, 
as may be required. It may be assumed that a good 
workman can easily fill 20 cube yards per day of 
underhanded stuff ; and 2d. per yard would therefore be 
a fair and ample remuneration to be paid to the work 
man alone for his labour. The contractor's expense 
for materials, superintendence, and contingencies, must 
be an after consideration, and will vary considerably, 
according to the quantity of work to be executed — 
whether it be wet or dry — the facility of obtaining 
workmen, and the accommodation which the country 
will afford them in the way of lodging — the kind 
of land and water-carriage by means of which the 
working implements must be brought on the ground — 
according to the season of the year — and to many other 
circumstances, which must render it extremely falla- 
cious to name any fixed sum, either as a per centage 
or other charge, which will in all cases be found a 
remunerating price. 



90 

The second class of earth, or that termed grafting 
stuff, is removed by a man standing above it, and 
forcing his tool (which thence derives its name of 
grafting, or more properly gracing, tool) into the earth 
by a stamp of his foot, which has the shoe protected 
with a piece of well tempered steel, fastened on with 
leather straps, and called a foot-iron. The increased 
time occupied in driving the tool into these grafting 
earths, may be taken as nearly equal as possible to 
the additional labour of one getter for every two fillers 
employed ; or in other words, it requires three men in 
grafting earths to perform the same work as two men 
in underhanded stuff: or again, the price of 3rf. per yard 
on the former will only afford the same wages as 2c?. 
on the latter. 

The third class, or getting stuff, presents greater 
variety than can possibly be found in the two former 
classes together. Even the clays alone are not more 
various in colour than in their different degrees of 
tenacity and solidity. They range through every grade 
of these qualities, from the softer kinds, which are 
usually grafted, up to the hard blue clays, which I 
have found more troublesome and expensive to remove 
than some of the hardest whin-stone and granite rocks. 
These latter I would rather encounter than some of the 
clays I have met with in the course of my practice in 
earth excavations. It has been before assumed, that a 
man can easily fill twenty yards of underhanded stuff in 
a day, and it might appear at first sight that (in the 
case of getting earths) after the stuff has been broken 
in pieces by the getters, it can be filled with the 
same facility as underhanded stuff. This however is not 
the case ; for I can aftirm, with great confidence, that 
men filling earth, requiring for instance two getters 
to each filler, and equal both in skill and strength to 



97 

the same number working in underhanded earth, will not 
fill more than half the quantity, or about ten yards per 
man per day. This great difference in the mere labour 
of filling the two kinds of earth, arises in some degree 
from the inconvenience of working in the very limited 
space to which the fillers are necessarily confined at 
the face of deep cuttings, and the frequent removals 
which the men in this small space are obliged to make 
from one particular heap of earth to another. The 
crowded state of the filling face is further increased 
by the pickmen, each of whom will occupy the same 
space as two fillers. A considerable time is lost by all 
the fillers previous to every fall of earth ; for whilst the 
piles are being driven down, it is impossible for the 
fillers to continue at work below. The fillers are also 
occasionally kept waiting until the earth, after its fall, 
is picked to pieces ready for filling. Lastly, the trouble 
of shifting roads is much increased in removing earth 
which is thus brought down in falls, and from these 
causes combined, the labour required to remove a given 
quantity of getting stuff is about double the labour 
necessary to remove the same quantity of underhanded 
material; and it is a certain fact, that the more ex- 
pensive any description of earth may be to get, it is 
always more expensive to fill. 

In order to bring down falls of the getting earth, 
and prepare it for the fillers, the process of undermin- 
ing is resorted to. When a longitudinal hollow in the 
direction of the mass to be brought down has been 
scooped out at the bottom of the cutting by properly 
pointed pickaxes, and the mass has been further sepa- 
rated from the great body of the earth by transverse 
upright chambers, which are also either picked or dug 
out by the grafting tool, a row of piles, about three 
^eet, or three feet and a half in length, and about five 



98 

inches diameter, properly shod and hooped with iron, is 
then driven down at the top of the mass by a beetle of 
suitable size, and by these means it is soon forced to 
the bottom of the cutting. 

If the earth be tolerably brittle and inadhesive, it is 
sometimes broken into several pieces, and rendered 
loose by the violence of the fall. Gravel, for instance, 
is very easily filled when once it has been forced to the 
bottom of the cutting; but most of the clays must after- 
wards be picked to pieces by pickaxes before they can 
be filled into the waggons. 

It will readily be seen that where it requires three 
men to get and fill 10 cube yards of earth per day, the 
price of their labour alone will amount to Is. per cube 
yard ; and accordingly it is by no means an uncommon 
case to find a contractor paying his men this high price 
when he is so unfortunate as to encounter these kinds 
of clay. In the case we have supposed, where two 
getters are required to supply each filler, it is evident 
that the getting alone will cost double as much as the 
filling, and the separate cost of each will appear from 
the following statement : 

s. d. 

One filler removes 10 yards at 4c?. 3 4 

Two getters prepare 10 yards at 8c? 6 8 

Price of getting and filling 10 cube yards . . 10 

which is equivalent to the pay of three men at 3s. 4c?. 
each. 

So much for the cost of the labour alone ; and with 
respect to the contractor's remuneration, it must be 
observed, that this ought to be estimated at a very 
different amount from that which he would find suffi- 
cient to clear all the charges of removing underhanded 
earths. In the latter case, his furnishings of materials 
need only consist of the barrows and planks or carts 



99 

for conveying the earth from the cutting; but in re- 
moving hard stuff which requires getting, he is obliged 
to provide picks, beetles, and piles, and to keep these 
constantly sharpened and in good repair. In addition 
to this, a very considerable increase of wear and tear 
will be occasioned to the waggons, carts, or barrows, 
and must of course be estimated accordingly. 

In connection with the increased expense of re- 
moving the harder kinds of earth, it may not be con- 
sidered irrelevant to glance at the general effect which 
will be produced in respect to the time of executing 
any work that requires much getting, as compared with 
other kinds of work more favourable in their nature. 
For instance ; if a cutting consist of underhanded earth 
which requires no getting, it may be assumed that fifty 
men will fill 1000 yards per day; but if the earth re- 
quire two getters to each filler, it is evident that thirty- 
three out of the fifty must be employed in bringing 
down falls, and breaking up the earth for the remaining 
seventeen, which number alone will continue to be 
actually engaged in filling. Suppose now that a man 
can fill 10 yards daily of this earth, the quantity ex- 
cavated by the whole fifty men will only amount to 
170 yards, or about one-sixth of the quantity which 
could be excavated of underhanded earth. We per- 
ceive therefore the necessity of perfectly ascertaining 
the nature of any excavation before attempting to 
estimate either the time or the cost of its execution. 

In assuming that a workman will not be able to fill 
more than 10 yards a day of earth which requires 
getting, it must be understood that this applies to earth 
of very unfavourable character; but if the earth be of 
such a quality as to require say one getter to two 
fillers, the labour of each filler may be averaged at 

H 2 



100 

13 or 14 yards per day, and the cost of filling in this 
case will therefore amount to about 3rf. per yard. 

With respect to the price of teaming, this may be 
fairly averaged at Id. per yard in estimating; but this 
must be varied according to the nature of the stuff. 
Sand, gravel, chalk, and clay, when dry, will always 
team well ; but any of these earths in a wet state will 
become clammy and adhesive to a degree which in- 
creases the time, the trouble, and expense of teaming. 

We may now proceed to establish the general rule 
for estimating the price of earth-work, founded upon 
the data which have been already laid down, and which, 
for the sake of greater clearness, it may be necessary 
to recapitulate. In earth which requires one getter to 
two fillers, the work done by the three men will be 

14 X 2 = 28 yards. In earth which requires two getters 
to one filler, the work done by the three men will 
amount to 10 yards; and taking the mean of these two 
amounts, we may assume the work of two men in earth 
requiring one getter to one filler, equivalent to 18 yards. 
Now it is evident, that in order to afford the same wages 
to the workmen in each of these three cases, the price 
to be paid for the work must always be inversely 
proportional to the amount of that work. Thus, if the 
value of three men's labour for one day be taken at 
105., or 120 pence, we have Vy, --[-(f , and \--^ for the 
price in pence of getting and filling the three kinds of 
earth respectively which have been described above. 

The price for the worst of the three kinds, namely, 
that which requires one getter to two fillers, will there- 
fore be ^'{•-Q° = 12(L per cube yard. The price for the 
next in order, or that which requires equal numbers of 
getters and fillers, will be \--^ = Cf pence per cube yard ; 
and the price for the best of the three, or that which 



101 

requires one getter to two fillers, will be ^^-^ = 4f pence 
per cube yard. In general terms, if F and G represent 
respectively the number of fillers and getters required 
to excavate any given quantity of earth, which may be 
represented by q, and if p express the wages of a 
single workman for the time which is occupied in ex- 
cavating the quantity q, then we have — — - — - = P the 
price per yard of excavating the earth in question. 

In proceeding to a brief review of the other descrip- 
tions of labour required in the construction of roads, 
the next in importance for roads constructed with a 
pitched foundation is probably that connected with the 
supply of stones proper for this purpose. In any 
country where an open quarry exists from which stone, 
no matter of what quality, is procured for building 
purposes, there Avill always be found an abundance of 
waste rubble, or small blocks of stone, which cannot be 
used for buildings of any description, and which there- 
fore are usually removed into the bottom of the quarry 
as useless material. This kind of waste stone is per- 
fectly adapted for pitching the foundations of roads, 
since it is only required that the stones shall range in 
depth from four to seven or eight inches from the apex 
or highest point to the base, and that the base shall not 
exceed about six inches in width. In any quarries 
producing stone for building purposes, it will surely not 
be too low an estimate to assume that rubble of the 
kind I have described may be bought on the ground for 
about 3d. per ton, since for any other purpose it would 
scarcely be worth the expense of carting. Beds of 
rock, which may be used for road pitching, are fre- 
quently found cropping out to the surface of the ground 
in places where stone is abundant. In such situations, 
even where no regular quarry has been opened, the 
stone may be got for about 3rf. or id. a load. In some 



]02 

places where the difficulties of procuring stone have 
been greater, I have paid from 6d. to Is. a load, this 
quantity being sufficient to pitch about five superficial 
yards of road. The charge of Is. per ton for pitching 
stones is decidedly high, and very much above the 
usual cost for which they may be procured. The price 
of loading and carting the stone from the quarries may 
be taken on an average at about Is. per cube yard per 
mile. Of course, if the distance of carriage be short, 
and the repetition during the day of the loading and 
unloading be more frequent, the cost of carriage will 
be somewhat in excess of this sum ; and on the con- 
trary, a long distance, estimated according to this rate, 
will afford the carrier too much profit. Probably for 
any distance of carriage between one and two miles, 
the price mentioned above will be found a fair remu- 
neration, but for shorter distances than a mile it will 
be far from a profitable bargain to the carrier. In any 
estimate of carriage, however, the situation of the quarry 
with respect to the road where the stones are to be 
used must be taken into consideration, because the 
state of the intermediate roads on which the stones are 
to be drawn is of great consequence. The price of Is. 
per yard per mile will be found reasonable in any 
country where the road leading from the quarry is a 
tolerably fair country road, notwithstanding the ruts 
may in some places be none of the smoothest, and the 
bottom none of the hardest. Where unreasonable in- 
clinations however exist on the communicating roads, 
the price will be rather insufficient. 

The labour of pitching the road after the stones have 
been carted and laid down ready for use, is worth about 
l^d. per superficial yard. The price of procuring gravel 
for the road covering, although materially affected by 
the circumstances which have been alluded to at the 



103 

beginning of this chapter, will not frequently exceed 
2s. per cube yard at the pit, after the gravel has been 
cleaned and sorted. I have however known instances, 
where the gravel required a great deal of preparation, 
in the way of breaking, screening, and even washing, 
in which the price of 4s. per yard has been paid, and 
this is the highest price with which I am acquainted. 
Nothing less than actual examination of the country, 
assisted by local information, will enable the surveyor 
to estimate, in a new country, the exact price to be paid 
for the gravel at the pit; but this price being once 
known, the value of the material laid down on the road 
may be taken at a shilling per yard per mile of carriage, 
in addition to the price at the pit. 

All brickwork required for culverts, bridges, shafts, 
or retaining walls, should be paid for by measure ; and 
here the price will depend upon the rate of workmen's 
wages and upon the facilities of obtaining bricks, lime, 
and sand. The lowest price however at which the brick- 
work necessary for roads should be estimated, is 11/. per 
rod of standard measure; because, should the work be 
undertaken at any lower price, the surveyor will have 
much trouble to prevent the introduction either of inferior 
materials or improper workmanship. This is far from 
being the average cost of the brickwork in road im- 
provements. In many instances where the work is not 
very massive, and consists of a large proportion of 
circular building, and where at the same time the build- 
ing materials are expensive, the price amounts to 15?. 
a rod, and the contractor even then is sometimes in- 
differently remunerated. The variation of price is often 
occasioned entirely by the different circumstances under 
which the bricks can be obtained and brought upon the 
ground. For instance ; I have myself bought bricks at 
one guinea per thousand, and at other times have paid 



104 

as much as two guineas, in both cases exclusive of 
carriage. Suppose now that the cheap bricks may be 
obtained close to the work ; and on the other hand con- 
sider a case where a long distance of bad road inter- 
venes between brick-kilns, where an expensive kind of 
brick is supplied, and the site where the building is to 
be constructed : it is obvious that a vast difference will 
be found in the prices of the brick-work, under these 
different circumstances, which sometimes occasion work 
to cost more than double the price in a more favourable 
locality. 

The building price alone to be paid to the workman 
may be taken on the average at about two guineas per 
rod, and the furnishing of lime and sand at two guineas 
more. It may be estimated that the quantity of 4500 
bricks will be necessary to finish a rod of brickwork, 
and the price of this quantity at the kilns, together with 
the cost of carriage at Is. per ton per mile, being added 
to the four guineas assumed for workmanship, lime, 
and sand, the price per rod will be obtained with suffi- 
cient accuracy for the approximate estimate ; but of 
course a per centage must be added for the contractor's 
profit and the supply of materials. 

Longitudinal side drains, three feet deep, with five- 
inch sough and tile laid in the bottom, averaging fifteen 
inches wide, and filled to the top with clean broken or 
boulder stones, may be estimated at from Is. 6d. to 
2s. Gd. per lineal yard, according to the facilities of 
obtaining the stones. Mitre drains will cost from 6d. 
to Is. 3rf. per lineal yard. 

Forming a footpath in the best manner, six feet in 
width, with a sod facing in front, will vary in price from 
Is. to 2s. 6d. per lineal yard. 

Having now gone through most of the works which 
the surveyor is usually called on to cstinuitc in carrying 



105 

into effect the improvement of roads, and made such 
practical observations upon the general method which 
ought to be followed in estimating works, as will enable 
the young surveyor to pronounce with some confidence 
upon the cost of any improvements he is about to 
undertake, I shall jjroceed to lay down a form of 
estimate which will serve, in some measure, to illus- 
trate the use of the preceding observations. 

The road for which the following estimate has been 
formed we shall suppose to be thirty feet^wlde, to be 
equally well constructed with any part of the London 
and Holyhead road, to have a footpath six feet mde 
on the north side, and to be defined on the south side 
by a verge, or raised ridge, elevated from the water 
table up to the height of the centre of the road ; the 
footpath and verge to have a sod neatly and firmly 
laid on their front facing. We shall suppose the extent 
of road to be improved, or newly constructed, to be one 
mile in length, and the earth-work to consist of 20,000 
yards of cutting of the following kinds : — 2000 yards of 
grafting stuff, to be wheeled two stages of 20 yards 
each; 5000 yards of getting stuff, to be removed two 
stages of 80 yards each, and requiring one getter to 
three fillers ; 5000 yards of the same stuff", to be removed 
by go-carts 3 stages, or 240 yards; the remaining 8000 
yards being bad stuff, to go 4 stages by go carts, and 
requires two getters to each filler. 

Probable Estimate of the Cost. 
Earthwork. 

Grafting earth will cost per yard for filling . . . Sd. £ s. d 

Wheeling by barrows two stages 2 

Contractor's material, profit, &c 1 

2000 at ed. 50 



Carried forward 50 



106 

£ s. d 

Brought forward 50 

Getting stuff requiring one getter to three fillers, to 
be removed by go-carts two stages, or 160 yards, 
will cost filling ocL, removing 2d., getting \d., 
teaming \d.; contractor for sharpening picks, 
furnishing beetles, &c. id., furnishing carts and 
light rails \\d. ; in all 9c?. per yard. 

6000 yards at 9rf. 187 10 

Getting stuff also requiring one getter to three fillers, 
to be run by carts three stages, will cost filling as 
before M., removing Sc?., getting \d., teaming \d. ; 
contractor as before for furnishings 2d. ; in all \Qd. 
per yard. 

6000 yards at \Qd. 208 6 8 

Hard getting clay requiring two getters to each filler, 
and of which each filler can only fill 10 yards per 
day, will cost for filling 4^., getting Sr/., furnishing 
picks, piles, beetles, &c. \id., furnishing go-carts 
and rails dd., carriage four stages Ad., teaming \d.; 
in all 1.9. did. per yard. 

8000 yards at 1*. 9ld. 716 13 4 

Road Pitching. 

Furnishing the stones which cost in the quarry 4d. 
per ton, and to be carted a distance of two miles, 
at 1*. per ton per mile, making in all 2,?. 4d. per 
mile ; then if one ton will complete 3§ superficial 
yards of pitching six inches deep, the quantity 

• •, c ., . , , •„ , I'^f'O X 10 
required for one mile in length will be — ^-^ 

= 5029 tons, at 2*. 4rf "! . . 586 14 4 

Labour of pitching ore mile in length, at Md. per 
superficial yard, or 17,600 yards at \id. 9113 4 

Footpath and Verge. 

Forming and completing footpath one mile in length, 

or 1/60 yards, at 1«. 9«?. 164 

Forming verge on the opposite side of the road, 
eighteen inches wide and nine inches high. 

1 760 lineal yards at 4d. 29 6 8 

Drainage. 

A longitudinal side drain on each side of the road, 
three feet deep, and filled with clean stones broken 

Carried forward 2024 4 4 



107 

£ s. d 

Brought forward 2024 4 4 

to the proper size, including a five-inch sough and 
tile channel to be laid in the bottom. 

3520 lineal yards at 1*. 6rf. 264 

Mitre drains at intervals of 40 yards, each drain 
being 12 yards long, will cost, at Is. per yard, 12*. 

44 drains at V2s. each 26 8 

Road Covering. 

Gravel to be laid down six inches in depth, a ton of 
which will cover about 4 superficial yards of the 
road, hence a mile in length will require 4400 tons ; 
then this will cost at the quarry 2s. 6d. per ton, 
carriage two miles 2«., spreading on the road 6rf. ; 
in all 5s. per ton. 

. 4400 tons at 5s. 1100 

Brick-work. 

In this mile of road it is necessary to build two cul- 
verts, and other brick-work is introduced; alto- 
gether 24 rods of work, at 12/. 10s 300 



Contractor's profit for superintendence, unforeseen 
circumstances in the work, and every possible 
contingency, at 20 per cent 742 



3714 12 4 
18 6 



56 4457 10 10 



I beg to observe, with reference to the preceding 
estimate, that although on many long lines of road the 
quantities of cutting and embanking, at particular parts, 
far exceed the amount I have assumed of 20,000 yards 
per mile, on the other hand it must be remembered, 
that in many districts the quantity of cutting will not 
be found nearly so great on an average of many miles 
of road communication. Again, the prices which have 
been assumed are of course hypothetical ; but of one 
thing I am certain, that 1 have not fallen into the error 
which so many hundreds have committed, of under- 
rating the cost of works to be carried into execution. 
I believe that in sreneral the materials can be obtained 



108 

for less than I have estimated; and throughout the 
lot of my statements,! have eareful.y guardedagams 
:hrL.er\r m.,eadm.^^^^^^^^^ 

;t:tr7:: thf ste :r p^^ng Mmse. to Ms 

r;".. the p---;-rertt;r— 

^ tiM^W intentions earned into etieci lui 
Ud be ore them, or the eontraetor seeking to der.ve a 

eason b e remnneration for exeeuting the^orks-to 
In and each I would say, that they may safely depend 
upon the fairness and candour of the statements I have 
ZZ since these are the result of a long course of 
Tnln pracHce and experience, during which I have 

bestowed unwearied attention upon the methods f 

estimating engineering works under every possible 

variety. 















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