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Cornell University Library pro-
duced this volume to replace the
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ware and equipment at 600 dots
per inch resolution and com-
pressed prior to storage using
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ard Z39.48-1984. The production
of this volume was supported in
part by the Commission on Pres-
ervation and Access and the Xerox
Corporation. Digital file copy-
right by Cornell University
Library 1991.RUDIMENTARY
PAPERS ON THE
ART OF CONSTRUCTING AND REPAIRING
COMMON ROADS.
CONTAINING
I.—A SURVEY OF THE METROPOLITAN ROADS, BY
S. HUGHES, C.E.
II.—THE ART OF CONSTRUCTING COMMON ROADS, BY
HENRY LAW, C.E.
III.—REMARKS ON THE MAINTENANCE OF MACADAMISED
ROADS, BY FIELD-MARSHAL SIR J. F. BURGOYNE,
Bart., G.C.B., Royal Engineers, Etc. Etc.
TOGETHER WITH
A NOTE ON THE TRUE CAUSES OF THE APPARENT FAILURE OF MACADAMISED
ROADS IN CERTAIN LOCALITIES, BY ROBERT MALLET, C.E.
Jtutrijj (Ibitton, foiijj ^bbitiona,
LONDON:
VIRTUE AND CO., 26, IVY LANE.
NEW YORK: VIRTUE AND YORSTON.
1868.PREFACE.
The “General Survey of the Chief Metropolitan
Roads,” with which this Treatise commences, is from
the pen of Mr. S. Hughes, C.E. It is valuable to the
student whose future and principal career is to be
that of a Road Constructor, as affording him the par-
ticulars of a number of examples of high roads, each
of which in its day of formation was characteristic of
perhaps the best results that Road Engineering had
then attained.
In the British Islands, however, Road-making was
undoubtedly in a very backward state previous to the
tiiicie of Telford; and to the fine examples in practice
and the stimulus given by his great Holyhead Road,
and by the Highland roads and bridges, was due in
great degree the marked improvement that charac-
terised our roads at the commencement of the present
century.
This General Survey is followed by the Treatise of
Mr. Law, in which the scientific principles upon
which lines of roads should be set out or determined,
and those which fix the art of their construction and
repair, together with those details of practice which
experience has best sanctioned, are set forth with lucid
c brevity.
The third part consists of the “Remarks on the
Maintenance of Macadamised Roads,” written by
Colonel, now Field-Marshal Sir John F. Burgoyne,
Bart., R.E., when Chairman of the Board of Works in
Ireland.VI
PREFACE.
The vast extension of roads made in that country
while Sir John Burgoyne filled that office, afforded
him great opportunities for observation, and his re-
marks are deemed highly valuable by Engineers of
Hoads.
The late Mr. John Weale solicited and obtained his
sanction as author, therefore, to reprint verbatim the
“ Reports,” or “ Instructions,” in which they originally
appeared, as a useful conclusion to this “ Elementary
Treatise on the Formation and Maintenance of Common
Roads,” which yet continue, and always must remain,
one of the most important means of intercommunication
in all countries. Sir John Burgoyne, with his usual
courtesy, gave his permission for their reappearance,
adding in his note, that “ nothing could be more glar-
ing, up to that day, than the barbarous, expensive, and
discreditable system of repair of Macadamised roads
in and about London, and that the object of these
Reports was to show how the evil might be remedied.”
There is still room for very great improvement in
the laying and repair of the Macadamised streets and
roads of the Metropolis, although the practice has of
date years in some respects improved. The admirable
practice of Paris, where, with far worse material than
is at our command, the results attained are so much
better, should be in part our school and example.
We have tardily adopted from thence the steam
road-roller; let its use be extended, and let us also
adopt the admirable methods of cleansing, watering,
and repairing of the French.
Robert Mallet.
June, 1866.CONTENTS.
General Survey of the Principal Metropolitan Hoads. By
S. Hughes, C.E...............................................
Rudiments of the Art of Constructing Common Roads. By
H. Law, C.E.
Chapter I. The Exploration of Roads .	.	.	*	«*	*
II.	On the Section of Roads ......
III.	On the Construction of Roads .	.	.	•	.
IV.	On Repairing and Improving Existing Roads .
V.	On Hedges and Fences............................
VI.	On Paved Roads and Streets .....
VII.	On taking out Quantities for Estimates	.	.	.	.
VIII.	Professor Mahan’s Elementary Essay on Road-Making.
Remarks on the Maintenance of Macadamised Roads. By
Gen. Sir John F. Burgoyne, Bart., &c., &c.,	&c.	•	•	.
Note on the Causes of apparent Failure of Macadamising
in certain Cases. By Robert Mallet, M.A., F.R.S., C.E.
Page
3
45
80
92
104
115
118
124
130
159
193
AGENERAL SURVEY
OP THE
PRINCIPAL METROPOLITAN ROADS.
With the view of arriving at some principles to guide us
in the laying out of roads in new districts of country, I am
not aware that any more instructive study could be pointed
out, than a brief survey of the physical features and geo-
graphical conditions which characterise the lines of the
present great roacjs leading from the metropolis to various
parts of the kingdom.
It may be objected to this, that there are few districts
which present any striking resemblance to the country sur-
rounding the metropolis • and that, consequently, rules laid
down as applicable to the construction of roads in this part
of England, would fail in their application to other districts,
and to distant countries. It may also be objected that,
with the exception of those designed by the Romans, the
roads of this country were not the work of any set of
people possessing superior wisdom and resources to the
native inhabitants, but were, in fact, gradually contrived
and executed by the natives themselves, during a long course
of centuries, whilst they were gradually emerging from
barbarism; and were continued and improved, step by step,
in proportion to the increase of our towns, the spread of
our commerce, and the advancement of our intellectual
resources. Tins latter fact would certainly lead to the
conclusion that our rqads, instead of being traced with
reference to the physical features of the country, would
often be made subservient in their direction to other fea-
tures and conditions; such as the position of towns or
hamlets already built, to the location of manufacturing
establishments, or the existence here and there of valuable
minerals, requiring the aid of superior land carriage in
order to render them of practical value.
The first of these objections exists more in appearance
than reality; for, although there may be many practical
A 24
BOAD-MAKING.
details peculiar to different districts of country when we
come actually to lay out a road in them, there is still much
similarity in the broad features which distinguish the sur-
face of the earth; and there is no such great variety in
these features as to call for many distinct divisions in
attempting a description of them. For instance, a line of
road may pass over a perfectly flat country, or it may lie in
the direction of a valley, or it may pass obliquely over both
valleys and their intervening ridges. Subdivisions of these
cases are possible, but still these are the three great condi-
tions under which roads have to be laid out: and some
roads have to encounter all three of* these cases.
To the second objection it may be answered, that while
we observe the faults committed by our ancestors in the
designs of their roads, we shall at the same time learn to
avoid them in our own colonies, where we profess to bring
the experience of civilised life to bear upon the wild desert,
the boundless prairie, or the tangled jungle. In applying
ourselves to the formation of roads in new countries, we
have peculiar mathematical resources to guide us in the
selection of those lines which are most direct, at the same
time that they are not less judicious than other routes. It
is probable that the use of surveying instruments, or, at
least, the use of instruments to determine the relative
bearings and position of objects, was unknown at the period
when most of the roads in this country were first formed;
and that not until the construction of maps such as those
of the Ordnance Survey, did the extreme and often unne-
cessary circuitousness of these roads become apparent. Now,
although in the colonies we do not yet possess Ordnance
maps, and may not possess them for many years, yet we are
able, by means of the theodolite, or even the circumferentor,
to determine not only the exact position of the terminal
points of the road, but to lay down the whole length of it,
to show the bearing and direction of every part, and so to
bring in the important elements of straightness and direc-
tion in finally determining the route, and comparing various
proposed lines together. To proceed, then, with our review
of the existing roads of this country,
CAMBRIDGE ROAD.
The first in order we shall take, is that which passes out
of London in nearly a northerly direction—namely, theCAMBBIDGKE BOAT).
5
road from London to Cambridge. This road emerges from
the east end of London, and, passing through Kingsland,
Stamford-hill, Tottenham High-cross, Tottenham, Edmon-
ton, Enfield, Cheshunt, Broxbourne, Hoddesdon, and Ware,
proceeds to Cambridge; from which place continuations
branch off to Huntingdon and Ely. The first peculiarity
in this road is observed at Stamford-hill, where it crosses
that remarkable horseshoe ridge of high ground which
encircles the metropolis on the west, north, and east sides.
This ridge, which is popularly well-known as the Hampstead
or Highgate range of hills, does not terminate at either of
those places, but is continued round in a circular, or, more
properly, a horseshoe form, by the following points, which
will usually indicate the highest part of the ridge. Com-
mencing with the highest ground in Hyde-park, the ridge
may be traced by Paddington, Barrow-hill, Primrose-hill,
Hampstead, Caen-wood, Highgate, Homsey-lane, and
Mount Pleasant—about one mile east of which winds the
Hew Elver, on its way to London. The ridge here almost
dies away, for about a mile and a half, into a depression,
through which some ancient river has probably had its
course; but it appears again about half a mile west of the
Cambridge road, forming the elevated points of Stamford-
hill, Upper Clapton, and Homerton, where, after skirting
the valley of the Lea for about three miles, it falls off into
the extensive flats of Bow, Bromley, and Stratford.
Stamford-hill is a ridge of inconsiderable height, with an
approach of about one in twenty on each side. This incli-
nation, although too steep to be sanctioned in the modem
system of road-making, which ought to have nothing steeper
than one in thirty, is here of less importance, as both the
inclinations are short, the steep part not exceeding a quar-
ter of a mile on either side.
Soon after crossing Stamford-hill, the road enters the
valley of the Eiver Lea, and keeps parallel to the Lea
and Stort navigation, at a distance varying between
half a mile and one mile, as far as Bishop’s Stortford,
where the navigation terminates. The road through Ware
branches off at Stortford, and proceeds by Eoyston to Cam-
bridge.
Immediately beyond Stamford-hill, the Cambridge line of
the Eastern Counties railway approximates nearly to the
turnpike road, and accompanies it in its course up the
valley of the Lea, the railway keeping the central positionROAD-MAKING.
between the road and the river. The river Lea, it should
be observed, on approaching the foot of Stamford-hill, is
turned out of its course by the horseshoe ridge already
described; and accordingly flows round it through Hack-
ney-marshes, and, passing by Bow and Bromley, falls into
the Thames at Bugsby’s-reach, immediately below Black-
wall. The railway, also, entirely avoids the high ground
between Stamford-hill and its terminus at Shoreditch.
Commencing at Stratford, out of the Norfolk line of the
Eastern Counties, the Cambridge line winds round on the
east side of the Lea, passing through the Hackney and the
Leyton-marshes, until it crosses the river a little below
Tottenham-mills, and then proceeds, as already described,
between the road and the river. The great detour made by
the railway will be seen from the fact, that from Shoreditch
to Tottenham High-cross the distance by railway is eight
miles; while, by road, the distance between the same points
is only four and a half miles.
A little south of Kingsland, this road crosses the Begent’s
Canal, which, by its communication with the Grand Junc-
tion, and the canals of the Midland counties, affords facilities
for the transport of the Mount-sorrel and Nuneaton sye-
nite ; and, accordingly, we find that the first tract of this
road, namely, for about two miles north of "Whitechapel
church, is made of this stone. The syenite is also partially
used with broken flint gravel for about a mile further. It
does not, however, appear to be used for the steep slopes of
Stamford-hill, a situation in which it would prove more
serviceable than in the flat district of Kingsland and
Daiston. Over Stamford-hill, and for several miles beyond,
the road metalling consists entirely of broken flints.
THE EPPING ROAD.
The next great road we propose to notice, proceeds out
of -London through Bow and Stratford, entering Epping-
forest at Leytonstone. It continues through the forest
about nine miles, passing by Snaresbrook, Woodford, Chig-
well-hill, Buckhurst-hill, High-beech, Jack’s-hill, and Ep-
ping. The road proceeds over Epping-plain and Thomwood-
common through Potter-street to Harlow, where it joins
the Cambridge road last described, about half way between
Hoddesdon and Sawbridgeworth. This road, for about ten
miles of its course, namely, between Stratford and Epping,EPPING BO AD.
7
may be said to occupy nearly the summit or watershed line
of the high country between the rivers Lea and Boding.
The ascent from Leytonstone to Woodford (two and a half
miles) is rapid, and the road then keeps nearly the summit
of the country, passing northwards towards High*beech,
parallel to the stream of a small feeder of the Lea. Beyond
High-beech its direction is parallel to a feeder of the
Boding, nearly as far as the Wake Arms on Jack’s-hill.
Passing over this high summit, the road somewhat descends
in approaching Epping. On leaving Epping, the road
ascends over Thornwood-common towards the sources of
Cripsey-brook, one of the principal feeders of the Boding.
Although it is here rather east of the real summit between
the Lea and the Boding, the road nearly divides the country
between them as far as its termination at Harlow.
An interest of no common kind appears to attach itself
to this forest road. It is probable that its track is very
ancient, and there is every reason to suppose that the wan-
dering gipsy, the cattle drdver from the northern and
eastern counties, and the pedlar—in days of yore a much
more important character than at present—made use of it
long before the valleys of the Lea or the Boding were
occupied by roads. Eor military purposes, it is easy to see
why a high district of country, lying between two valleys,
should afford the most favourite site for a road, provided its
undulations offered no very striking obstacle. We know
that in former days this great forest of Epping was a royal
hunting-ground; and there are not wanting, in the present
day, names to serve as memorials of such a fact. About
two miles north-east of Chingford, stands Queen Elizabeth’s
Lodge; while Eox Inn, Eoyal Oak Inn, Hunter’s Hall, and
similar places scattered about the forest, remind us of the
sport which was there followed, and of the noble personages
who shared in it. There are many indications of wells and
springs of medicinal and healing virtues all along the main
road through the forest. These were, probably, waters
containing certain proportions of alkaline substances, such
as those of Epsom, Wandsworth, Bagnigge Wells, Beulah
Spa, and numerous other spots in and about London.
The ancient character of this road, and the fact of its
having been a favourite highway for the traffic of former
times, (marked by a circumstance from which one might
also deduce another consequence, pointing to the lawless
violence of that period,) is to be found in the name of a8
BOAD-MAKING.
spot—Turpin’s Cave—which will he found marked on the
Ordnance Map, in a hollow on the right of the road, oppo-
site the twelfth mile from London. The many natural
advantages enjoyed by this road, passing through an elevated
district, chiefly of gravel, with patches of clay, retaining
water where required, and yet abundantly drained by the
numerous feeders of the Lea and the Boding, joined to the
magnificent prospects which swell before the view on either
side, have caused it to become a favoured residence with
many of the most respectable and wealthy citizens of
London; and, accordingly, the Forest road boasts an un-
usually large number of houses, villas, and mansions, of
superior character.
Although the track of this road is probably very ancient,
it has been much improved of late years by cutting down
the hills and filling the valleys, so as to reduce the inequali-
ties of the undulating surface of the forest. The improve-
ment thus effected may be judged from the fact that on
the Chingford road, a parallel line lying on the west side of
the forest, where the irregularities are not so prominent as
in this central line, there are inclinations as steep as eight
and nine to one; whereas, on the whole of the Epping
road, there is no inclination exceeding one in thirty.
Where the road has been lowered, the cuttings are com-
posed of a very gravelly clay, which has uniformly slipped
to a great extent, no precautions having been taken to pre-
vent the slipping, by drainage or otherwise. The same
remark applies to the embankments, which, besides absorb-
ing the material from the cuttings, have been partially made
up from side cuttings, excavated at the base on both sides,
where the land is not of much value. The whole metalling
of this road consists of the round pebbly flint gravel, which
is found so abundantly in most parts of the forest; and in
summer, or tolerably dry weather, the surface is commonly
in very good order.
This road, as far as Stratford, is principally composed of
Mount-sorrel syenite; in addition to which, from White-
chapel church, where the street-paving ends, as far as Bow,
a trackway, of eight feet wide on each side, is pitched with
regular granite paving stones, similar to the street pitching.
This is of great service for slow heavy traffic, by which
the trackways are chiefly used. This part of the road is
from fifty to sixty feet in width between the footpaths.CHIPPING ONGAR BOAD.
9
CHIPPING ONGAR ROAD.
The next road in order is that which passes up the valley
of the Boding to Chipping Ongar, where it joins a line of
road leading out of the Epping road last described, at
Epping itself, to Chelmsford. This Chipping Ongar road
branches out of the Epping road at Leytonstone, and pass-
ing off in a north-easterly direction, falls into the valley of
the Boding, nearly opposite Woodford. Keeping close to
the river for about a mile, it crosses over at Woodford-
bridge, and then proceeds on the east side, by Chigwell and
Wolston-lodge, up to Abridge, where it again approaches
the river. Beyond Abridge, the course of the river is nearly
eastward for about two miles, during which the road closely
follows it, crossing at Passingford-bridge, from which point
they both pursue a north-easterly course to Chipping
Ongar.
There are great defects in this road, and it evidently
appears to have been designed to suit a succession of pri-
vate and inferior interests, instead of the general and public
convenience! Between Woodford-bridge and Abridge, a
distance of four miles, this is more particularly the case;
the road for some distance between these points, as at
Chigwell for instance, being fully a mile from the river,
without answering any ostensible purpose, except that of
encountering very high and undulating ground, instead of
a perfect flat. Every engineer knows that, in following the
course of a river, either for a railway or a common road, it
is advisable to recede from the river, where secondary val-
ley’s intervene, so as to cross these high up, where the depth
oi filling will be small; and, on the other hand, to approach
the river where promontories of high land intervene with
these secondary valleys, so as to reduce the depth of cutting
as much as possible. The very opposite has been done in
this case, inasmuch as between Abridge and Woodford-
bridge the river is turned from its course, and diverted to
the west, by the high projecting land jutting out from
Hainault-forest; and the road, instead of following this
westward bend of the river, actually projects in a cor-
responding maimer to the eastward, so as to catch a great
deal of the high ground of the forest, both north and south
of Chigwell. This defect in the construction of the road
has probably been occasioned in accommodating an extensive
group of villas and superior residences in the neighbour*
a 310
BOAD-MAKIK0.
hood of Chigwell, Wilcox-green, the Bolls, Wolston-lodge,
&c.; and, although it might be very desirable for the
owners of these to seek an elevated situation on the dank
of Hainault-forest, commanding views across the low country
of the Boding, and bringing into the landscape the many
objects of interest which crowd the opposite slopes of
Epping-forest, this still appears to be a very imperfect
reason for carrying the road over so undulating a country,
to the permanent injury and mischief of all who have ever
to use the road. The first error is made in carrying the
road suddenly down from Snaresbrook-farm to the Boding,
where the descent increases from one in thirty-two to one
in seventeen, and continues at this latter rate for some
distance.
Again, at Woodford-bridge the road rises much too sud-
denly from the river, and strikes at once into the high
ground, which, in all such cases, should be gradually skirted.
A considerable part of the ascent from the river to the
turnpike-gate, at Wilcox-green, is at the rate of one in
twenty. The road then continues with moderate undula-
tions till about the tenth mile, when it descends to Chig-
well-brook, at the rate of one in twenty-five, which increases
at one place to one in nineteen. The ascent from the stream
up to the vicarage is at the rate of one in twenty. Beyond
the vicarage commences a long and uninterrupted descent
of about a mile and a half, beginning with one in sixty, in-
creasing to one in twenty-five ; then a short piece of one
in forty-five, increasing to one in thirty; and at BolTs-farm
becoming one in twenty-five, and continuing about the same
rate to the bottom of the hill, which is little above the val-
ley of the Boding.
It will be seen, from the preceding glance at the levels of
the existing road, how very inferior it is to a line which
might be traced alongside the river, instead of passing over
the high ground of Wilcox-green and Chigwell. An excel-
lent Hne of road might be traced from Snaresbrook-farm,
where it should leave the present road, descend very
gradually the slope of the Boding valley, passing between
Bay-house and Bay-lodge, and crossing the river about
opposite Monkham, or Lord’s Bushes, and then sweep
round on the east side of the river, keeping within a dis-
tance of twenty or thirty chains, and passing between the
stream and Wolston-lodge, and might join the present road
between the twelfth and thirteenth mile from London. .CHELMSFORD ROAD.
11
Between Abridge and Chipping Ongar the road is laid
out more in accordance with the natural requirements of
the country, although there are several spots where great
improvements would be made by trifling deviations.
THE CHELMSFORD ROAD.
The next in order is the great Chelmsford road, which also
passes out of London through Bow and Stratford, and con-
tinues on through Great Ilford, Romford, Brentwood, and
Ingatestone, to Chelmsford, where it divides into two
branches, one of which passes by Braintree and Halstead
to Bury St. Edmunds, and thence by Thetford to Lynn,
and various other parts of the Norfolk coast; while the
other branch goes on by Witham, Colchester, and Ipswich,
to Norwich, where again numerous other roads diverge to
Cromer, Cley, 'Wells, and other sea-ports.
It is remarkable, that this road consists of a series of
nearly straight lines from one town to another, the bends
taking place at the towns, while the intermediate parts are
straight. Thus, from London to Bow is straight; at Bow,
the road bends more to the north, and is straight to Strat-
ford—there it bends again to the east, and is nearly straight
to Romford, seven miles: at Romford, it bends again to the
north, and is nearly straight to Brentwood, six and a half
miles; there it bends still to the north, and continues
nearly straight through Ingatestone to Chelmsford, distant
twenty-nine miles from London. This road is closely
accompanied all the way to Ipswich by the Norwich branch
of the Eastern Counties railway. The railway keeps on
the north side of the road for about eight miles out of
London, when it crosses to the south side, about a mile
beyond Ilford, and proceeds nearly parallel as far as Brent-
wood, where it makes a remarkable curve to the south-east,
in order to gain lower ground at that summit, and then
continues again parallel to the road, as far as Widford,
about a mile south of Chelmsford, where it again crosses
to the north side of the road, and so passes Chelmsford on
the west or north-west side of the town. The engineer-
ing difficulty of passing over so low a level as that of the
Chelmer, on the east side of the town, is supposed to have
dictated this deviation to the north-west. There is, at
present, an extensive viaduct over the Cam, above the town,
and this work would, of course, have been much more12
BOAD-MAKIffG.
serious, if constructed over the low level of the Chelmer, on
the east side. "Without this supposition, it is not easy to
conceive why that side of a town, possessing a navigable
communication with the sea, should be deserted for the
other side, where no such facility exists for transverse com-
munication.
This road, as far as Brentwood, eighteen miles from Lon-
don, may be said to pass up the valley of the Thames,
crossing the following feeders of that river; 1st, the Lea
at Bow, three miles from its mouth; 2nd, the Boding at
Ilford, about four miles from its mouth ; 3rd, the Bourne-
brook at Bomford, about five miles from its mouth; 4th,
the Ingreburn-brook, three and a half miles north of Bom-
ford, about eight miles from its mouth. All these streams,
and a few intermediate ones, also crossed by this road, flow
into the Thames, and their mouths, of course, are the points
of junction with that river. The country through which
the road passes is very flat from London to Ilford, seven
miles: the road then between Ilford and Bomford rises into
a somewhat higher country, skirting the southern slope of
Hainault-forest, and might perhaps be improved by a diver-
sion southward, in some part of this length.
After crossing the Bourne-brook at Bomford, the road
ascends to a summit opposite Hare-hall, and then descend-
ing, crosses a feeder of Ingreburn-brook, and runs parallel
for about a mile with the brook itself, which it crosses at
Pitwell-bridge, and then takes the course of another of its
feeders, as far as Brentwood; here is the summit of country
which divides the waters flowing to the Thames, from those
which flow in a north-easterly direction into the Black-
water. One of the principal streams of the Chelmer rises
about a mile south-east of Brentwood, and flows nearly in
the direction of this road to Chelmsford, where it joins the
Chelmer* in its course to the Blackwater at Maldon. The
road north of Brentwood passes down the valley of this
stream, crossing numerous tributaries which flow in a
south-easterly direction, and thus affording an example of
that very common case in which a road passes in the direc-
tion of a river-valley, and crosses all the secondary valleys
and intervening ridges. After crossing the Cam and the
Chelmer at Chelmsford, the road passes on through a more
level country to Witham and Colchester.
* The Chelmer navigation communicates at the port of Maldon with the
Blackwater, an arm of the sea.BARKING ROAD.
13
THE BARKING ROAD.
The next in order is called the Barking road, beyond
which place it is continued on through numerous small
towns and villages in Essex, till it reaches Southend and
Great Wakering, being there stopped by the line of the
eastern coast. This road owes its elevation to the rank of
a main line of turnpike road to a comparatively recent date,
and consists of a number of short pieces of road joining a
series of small towns or villages, all united together, the
gaps being made up by new pieces of road, and the whole
formed into one continuous line. We may hence expect to
find that its course is somewhat circuitous; and accordingly,
although the country is nearly quite flat throughout, we
find it bends at every group of houses, into the direction of
the next group lying in anything like the proper direction.
This is remarkably the case east of Bainham, twelve miles
from London, beyond which place the road is a complete
series of zigzags. This road passes out of London through
Limfehouse, and proceeds to Bainham, through Plaistow
and Barking. In all this part, it lies entirely in the valley
of the Thames, barely skirting the high ground which
adjoins the marshes, but lying more immediately in the
marshes themselves, and so crossing, at moderate eleva-
tions, the various streams which debouch into the Thames.
Beyond Bainham the road passes on through Wennington,
Aveley, and Stifford, making a considerable bend at Wen-
nington, in order to keep clear of the marsh of that name.
THE DOVER ROAD.
Having now completed one-fourth of the circumference
round the metropolis, namely, a quadrant from its meridian
to the river Thames, which flows nearly towards the east,
we shall next take the first important road which occurs
south of the river ; namely, the old Canterbury and Dover
road. This famous road, so well known, and so much used
before the present South-Eastern railway became the great
highway to the continent, boasts of a very high antiquity.
Not only is part of this road mentioned by Shakspeare,*
but it is known that other parts of it were the work of the
Bomans, and formed the great line of way called the Wat-
* Gad Vhill, opposite the village of Higham, is the scene of the robbery
of the Sandwich carriers.—See Shakspeare's play of Henry V.14
BOAD-MAKIN O.
ling-street, leading from London to Canterbury. This road
proceeds out of London from the Elephant and Castle,
where the first part of it is called the Old Kent road, and
the Dover road. It then proceeds through Deptford, and
passing at the back of Greenwich-park, crosses Blackheath,
and passing over Shooter’s-hill, goes on through Bexley
and Crayford, to Dartford.
The part of the road comprised between Deptford and
Dartford is very hilly; and though geographically located
in the valley of the Thames, yet it derives very little advan-
tage from this, being situated in a high and hilly tract of
country, which closely approaches the river at Greenwich,
Woolwich, and Erith; and the road keeps high up on this
elevated ground, crossing the various streams not far from
their sources. The part between Greenwich and Dartford
being quite straight, was probably part of the old Watling-
street, and being designed by the Bomans essentially for
military purposes, was carried by them at such a high level,
as to command the adjacent country, in order that it might
afford sites for observing the motions of their enemies, and
cause the earliest intelligence of a rising or surprise to be
circulated with the utmost rapidity from one station to
another.
It is impossible to review here all the modem interests
that may make it desirable to preserve the road in its pre-
sent direction; but assuredly, as far as levels and the
physical features of the country are concerned, the road is
a very bad one, and far inferior to one which might be
formed by Woolwich, Erith, and thence across the Dartford-
marshes, to join the present Dover road at the village of
Greenhithe, about two miles beyond Dartford. Such a
road, which might either be made within the marshes, or
skirting the rising ground all the way, would be just one
mile longer than the present road; but this excess of dis-
tance would be amply compensated by the improved levels,
and consequent decrease of draught for the horses.
It is remarkable that the next length of this road,
namely, between Dartford and Rochester, is entirely deviated
from, by the modern road which passes round by Green-
hithe, STorthfleet, Gravesend, Chalk, and Gad’s-hill, till it
falls again into the Homan road at Strood. Erom Dartford
to Strood, by the old Watling-street, which is nearly
straight, and may still be traced, with the exception of
about a mile at Swanscomb-park, the distance was elevenDOVEB BOAD.
15
miles, while the distance by the present road is exactly
twelve miles; and here again the distance is as amply com-
pensated as it would have been by a deviation between
Greenwich and Dartford. It may be worth notice, that
Gad’s-hill, the name of a spot already referred to as used
by Shakspeare, is on the deviated road between Gravesend
and Strood, showing that in his day the traffic was carried
on in the same route as at present. This point of Gad’s-
hill is on the Higham ridge of high ground, through which
the Thames and Medway canal is carried by a long tunnel,
about a mile east of Gad’s-hill.
After crossing the Medway at Strood, and proceeding
through Eochester and Chatham, the road proceeds in a
perfectly straight direction through Eainham and Milton,
by Sittingboume and Eaversham, to Canterbury; the whole
of this part being the same road as that used by the Eo-
mans, under the name of Watling-street.
The following notes of the gradients on this road, be-
tween Deptford and Dartford, will show how much has
been sacrificed in order to obtain a straight line: the ascent
from Deptford to Blackheath is at first one in seventeen;
opposite a new church on the north side of the road, one in
fourteen; a little further on, one in eleven: rounding off
again to one in fourteen; and so continuing nearly to the
Green-man inn.
The ascent of Shooter’s-hill, at one hundred yards west
of the eighth mile-stone, is one in eighteen; at fifty yards
west of ditto, one in eleven; at the mile-stone, one in
eleven ; the hill then rounds off gradually to one in
eighteen; and so continues for some distance. The descent
from Shooter* s-hill towards Bexley soon becomes one in
sixteen, and increases to one in thirteen; at fifty yards
further on, one in eleven, and so continues for several
hundred yards. By degrees, it becomes one in thirteen,
and, near the bottom of the hill, slopes off to one in twenty-
two, and so gradually diminishes. Even these gradients
at Shooter’s-hill have been attained by a considerable cut-
ting on the west side, which has been carried westward to
embankment, to raise the foot of the hill. The material is
probably plastic clay, which has slipped to a considerable
extent.
These disadvantageous gradients might all be avoided by
taking the road by Woolwich, and so along the marshes of
Plumstead to Erith, as before pointed out. The road1G
ROAD-MAKING.
through Lee, Eltham, and Bexley, which falls into the
Dover road at Crayford, is also very superior in point of
levels, as it entirely avoids both Blackheath and Shooter’s-
liill, and the access in length is inconsiderable.
THE MAIDSTONE ROAD.
This road passes out of London, like the last, by the
Kent road and Dover road; out of which it branches at
Deptford, and continues by Lee and Eltham, Eootscray,
Earningham, and Wrotham, to Maidstone, where it divides
into two lines, one of which goes on to Hythe, Eolkstone,
and Romney; while the other takes a circuitous course to
Tenterden and Rye.
Erom Deptford nearly to Eltham, this road follows the
course of a branch of the Ravensbourne. At Eltham, it
turns suddenly almost at right angles towards Eootscray,
passing over a summit, and descending to the level of the
Cray, at the latter place. Erom Eootscray, it passes on in
a south-easterly direction, and crossing another summit,
descends at Earningham to the level of the Darent. Erom
this place the road rapidly ascends into an elevated chalk.
district, by Hever-farm, Portobello, and the Horse and
Grroom, and then rapidly descends into Wrotham; and
thence on through a tolerably flat district of country, lying
between the chalk escarpment and the green-sand range to
West Mailing and Ditton, and thence to Maidstone.
The descent at Wrotham must be very steep, and although
a little artifice has been resorted to with a view of increasing
the length of the descent, and so reducing its steepness,
this has not been sufficiently carried out; and this passage
of the chalk range consequently remains a highly objec-
tionable feature in this road. If the road had now to be
made, it is probable that a very different course would be
decided on; and the modem engineer would certainly look
for some natural pass through the chalk, and if he could
find no river passing through it from the south, would next
seek some spot where a great depression existed, indicating
the probability of some ancient rush of waters having for-
merly taken place there. Nothing of the kind has been
done here ; the passage at Wrotham appears to be a forced
and unnecessary one, neither judicious nor expedient, and
quite inconsistent with the most ordinary and common-place
of the rules applicable to such a case Nor shall we haveLONDON TO TU1BBIDGE.
17
to search far for such a gap in the chalk, for Maidstone
actually stands on the Medway, which flows northward
completely through the chalk by Rochester and Chatham.
He would probably, therefore, carry his road straight up.
the valley of the Medway, to Cuxton, where he would cross
it, then continue it by Nursted and Longfield to Sutton-at-
Hone, where he would cross the Darent, using where prac-
ticable pieces of existing road which lie nearly, or quite, in
the proper direction; and thence in a straight line to
Footscray, making the distance from Footscray to Maid-
stone twenty-three miles, exactly as at present, with the
advantage of intersecting a much more level country, and
so obtaining a better road.
The principal branch of this road proceeds from Maid-
stone to Langley and Sutton Valence, where it crosses the
green-sand formation, and then proceeds by Headcorn
through the wealden district of Kent.
The gradients on this road are tolerably good, until it
reaches the chalk district. The principal hill is at Eltham,
where the inclination on each side does not exceed one in
twenty.
HOADS FROM LONDON TO TUNBRIDGE.
Thebe are two roads branching out of the Maidstone-
road last described, which lead to Tunbridge. The first of
these commences two miles north of "Wroth am, crosses the
chalk range at Old Terry’s Lodge, and passes by Ightham
and Shipbome to Tunbridge. This road is liable to the
same serious objection as the one by Wrotham, namely,
that it crosses the chalk where no natural gap nor depres-
sion exists, and that within a mile of the other crossing at
Wrotham. The other road commences at Farningham, and
passes up the valley of the Darent by Lullingstone, Eynes-
ford, Shoreham, and Otford; joining the real London and *
Tunbridge road at Maidstone. This road passes through a
very easy country, and is laid out on the sloping ground of the
valley of the Darent; yet although every facility is afforded
for making a road almost practically level, and with no in-
clination steeper than would be requisite for good drainage,
it does not appear that the natural advantages of the
ground have been followed in a judicious manner, although
there is no steep inclination in climbing over the chalk, as
at Wrotham, or Old Terry’s Lodge. We come lastly to
the so-called direct Tunbridge-road, which although shorter
than either of the others, by Ightham or Otford, is still18
ROAD-MAKING.
made very circuitous by a great number of waves and bends,
for which it is usually difficult to conceive any adequate reason.
This road commences out of the last described, between
Deptford and Lee, and following the course of the Havens-
bourne river, passes through Bromley, and on to Bromley-
common and Famborough. This latter place is situate on a
ridge which nearly ranges with the sources of the Bavens-
bourne and the Cray, and the country here becomes very
irregular in its formation, the valleys and ridges assuming
various directions, and presenting serious difficulties to any
road or railway passing across them. This continues as far
as the summit of the chalk, nearly to the Star inn, opposite
Chevening, a distance of about five miles in a straight line
from Famborough.
The road, however, owing to its numerous bends and
curves, measures about six miles between these points. At
the Star, it descends, by a circuitous course, to tl\e com-
paratively low country between the chalk and the green-
sand, and then ascends by Eiverhead and Sevenoaks, till
it reaches the summit of the sand range, at the south
corner of Knole-park, where it rapidly descends this second
range, and passes on through a tolerably level country to
Tunbridge.
The road here separates into several branches, one of
which proceeds by Tunbridge Wells and Mayfield, to Pe-
vensey and East Bourn. Another goes by Lamberhurst,
Hobertsbridge and Battle, to Hastings; and a third goes
by Lamberhurst and Sandhurst, to Bye.
ROADS FROM LONDON TO LEWES.
The first of these, by W'esterham, Edenbridge, and Hart-
field, is identical with the Tunbridge road, as far as Bromley-
common, where it takes a more southerly direction than the
Tunbridge road, following closer the valley of the Bavens-
boume, up to Keston-common. At Keston village, the
road makes a great angular projection westward, in order
to avoid Holwood-park, and then enters the same elevated
irregular chalk country as that already described between
Farnborough and Chevening. The bends on this road are
also very considerable between Keston and Betsom’s-hill
farm, the summit of the chalk ridge. From Keston to
Bradfield, about one mile and a half, it passes very obliquely
over a projecting tongue of the chalk, and then there is an
attempt to take advantage of one of those long, and some*LONDON TO LEWES.
19
times straight coombes of the chalk, which have been hol-
lowed out by ancient currents of water. This coombe runs
out, as it is called, before coming to the summit at Betsom’s-
hill, so that it forms no gap or depression in the chalk; and
it does not appear, even where the coombe is a distinct and
decided hollow, that the road has been laid out with any
remarkable judgment. The road descends from the high
chalk country at Betsom’s-hill, and passes on by "Westerham
tu'Westerham-common and Cockham-hill-common, the sum-
mit of the sand range, which it penetrates in the same bold
manner as it has already done with the chalk; and having
arrived in the weaiden district, proceeds through a tolerably
flat country, by Edenbridge and Cowden, on to Hartfield,
and by Little Horsted, to Lewes.
The other road to Lewes is identical with the road to
Brighton, (which will presently be described,) as far as
Biddlesdown, about thirteen miles from London, where it
diverges to Godstone, passing over a more favourable dis-
trict of the chalk than those which have lately been noticed.
The chalk summit is passed about a mile north of Godstone,
at a point where there is a considerable depression. The
road then proceeds through the village of Godstone, on to
Tilburstow-hill, which it crosses, and which is composed
chiefly of sand. It then passes on through rather an ele-
vated and irregular part of the weaiden district, by Blind-
ley-heath, Erogwood-heath, and Eelbridge, on to East Grin-
stead, whence it goes on to the west side of Peppingford-
park and Sheffield-park down the valley of the Ouse, to
Lewes.
ROADS FROM LONDON TO BRIGHTON.
The first of these is the old road through Croydon, which
leaves London by the Elephant and Castle, and, after pass-
ing through Croydon, proceeds along Smitham-bottom, up
to Merstham, where it intersects the chalk summit, and
then goes on, by Bed-hill and Earl’s-wood-common, to Hor-
ley and Crawley. This is the weaiden district, in which
the road continues till it meets with the chalk range of
the South Downs, which it ascends at Clayton, and thence
passes down to Brighton.
Most of the roads we have lately been considering have
passed southwards out of London, either up valleys leading
them on to the elevated heights of the chalk formation, or20
UOAD-MAKING.
over comparatively low tracts, sloping gradually upwards to
the chalk, and have experienced no difficulties until they
reach the irregular coombes, or broad furrows, with their
intervening ridges, which everywhere distinguish the chalk
district on the south side of London. The coombes them-
selves are usually filled with deposits of flint gravel, the
debris of chalk, much mixed with the actual matter of chalk,
while the elevated ridges between are usually composed of
chalk itself. The beds of flint gravel, intermixed here and
there with chalk wash, frequently overlie the edges of the
plastic clay; and the hollow points, where they cease and
where the clay commences, are usually the sources of
streams, which flow over the plastic clay into the Thames,
which drains the whole district.
The Bavensboume and the Wan die are the principal
streams which rise in this way in this part of the country;
and it is remarkable that there is a considerable breadth *
between these rivers, and that all the intermediate country
is too high to be penetrated by any but secondary streams,
or feeders, of these two principals; that no stream of any
consequence goes through it to the Thames; and, in fact,
that it embraces no streams whatever except those which
arise from the elevated strata of the district itself, and which
are quite unconnected with the extensive chalk country
lying beyond it.
The country drained by the Wan die and the Bavens-
boume is of a triangular shape, the apex being at Selhurst-
wood, about a mile north of Croydon, where the sources of
the eastern branch of the Wandle and the most western
branch of the Bavensboume are within a quarter of a mile
of each other. These two streams take a circuitous course
round the high district in question, and diverge so far from
each other that the distance from the mouth of the Wandle,
at Wandsworth, to that of the Bavensboume, at Deptford,
is not less than eight miles in a straight line. The high
country lying within these limits includes Clapham-common,
Brixton-hill, Herne-hill, Dulwich, Peckham Bye, Nunhead,
New Cross-hill, Brockley, Forest-hill, Sydenham-hill, Dul-
wich-common, Streatham-hill, TJpper Tooting, Streatham-
common, Upper Norwood, Penge-common, Beggars’-hill,
&c. The district which embraces these spots must be ex-
ceedingly well known to those at all acquainted with the
country round London; but it may not at the same time
have attracted general observation that, with the exceptionLONDON TO BBIGHTON.
21
of the Brighton road, now about to be described, and which
lies rather on the eastern slope of the high ground, there is
no main road leading through it; and that the distance
between this road and the Bromley road last described is
at no place less than four miles; and that at Bromley itself
the distance between the two roads is upwards of six miles.
It is true that there are many roads in most parts of the
district here referred to, leading to all the numerous places
above mentioned; but none of these are main roads, nor
does any of them ever form the road from the metropolis to
places lying beyond the elevated district in question.
The Brighton road, leaving London by the Elephant and
Castle, and passing to Croydon, through Brixton and Streat-
ham, passes, as we have said, through this district, but quite
on the east side of it, where the elevations are much more
depressed than in the more central parts by Norwood, Sy-
denham, and Eorest-hill. In fact, the rise from St. Mat-
thew’s church, Brixton, up to Brixton-hill, and on to Streat-
ham-hill, is the most considerable one between London and
Croydon. The ground at Streatham-common, although high,
is tolerably level; and immediately beyond the common
commences a comparatively new piece of road, three miles
long, and almost perfectly straight the whole way into Croy-
don ; so that upon the whole, the Croydon part of this road
may be termed tolerably perfect, with reference to its selec-
tion and design. It may be added, that though not quite
straight between the Elephant and Croydon, as it bends at
Streatham to the extent of a mile and a half west from a
straight line, yet this appears judicious, as a much lower
country is thereby intersected, and the ascent is much less
than it otherwise would be. The ascent from the Elephant
to Croydon is about 140 feet; and on any other route in-
tended to shorten the length of the line, it is probable that
in several parts the country would attain a greater height
than the level of Croydon, so that there would be a loss of
power in the unnecessary ascent.
Beyond Croydon this road passes up an extensive coombe,
or hollow in the chalk, termed Smitham-bottom, winding to
a trifling extent, to accommodate itself to the irregularities
of the ground. The Brighton railway passes at several
places so close to the road, that diversions of the latter have
been made to keep it clear of the deep cuttings and spoil-
banks of the railway. In passing the Merstham summit,
the railway goes through a tunnel more than a mile in22
UOAD-MAKIKG.
length, with cuttings of great depth at each end. These
are rendered necessary by the comparatively flat inclination
of twenty feet per mile, which has been adopted for the
railway on both sides of its summit, whereas an inclination
of 176 feet per mile on the road will about correspond with
twenty feet per mile on the railway. Descending from
Merstham, the road passes across the flat district of the
gault and upper green-sand to Red-hill, where the soft sand
has been cuf through, and enters Earl’s-wood-common, the
edge of the wealden district. From this place, it continues
through a tolerably flat country, and in a tolerably straight
direction, till it again encounters the chalk at Clayton, near
Brighton.
The other road to Brighton, commonly called the Sutton
road, passes out of London by Clapham, over Clapham-
common, and then proceeds, by Tooting and Mitcham-grove,
to Sutton. Hence it takes nearly a straight course across
the chalk to Banstead-downs, passing over Banstead^heath
and Walton-heath, whence it bends considerably to the
east, in order to gain a somewhat more favourable point for
crossing the chalk. About a mile north of Beigate, the
descent from the chalk commences, the road doubling back
towards the west, in order to diminish the steepness; and
when about half way down, passing for some short distance
quite in a westerly direction, and then making straight for
Beigate, which it enters rather on the west side of the
town. The road emerges from Beigate rather on the east
side, and then skirting Lord Somers’ park, passes by a
deep cutting at Cockham-mills, through the sand ridge, and
then proceeds across the wealden district in nearly a straight
direction over Hookwood-common, to Povey^cross, near
Horley, where it falls into the other Brighton road, at the
distance of twenty^seven miles from London.
The first part of this road, from Kennington to the cross-;
ing of a branch of the Wan die at Tooting, lies still more tq
the westward, on the slope of the high country of Brixton
and Norwood, than the other Brighton road. Clapham?
common is rather an elevated point, but all the inclinations
are very moderate as far as the street of Sutton, where the
ascent is steep. Here also commences the true chalk
country, which continues to ascend over the Downs and
over Banstead-heath and Walton-heath. Between Sutton
and the point of descent from the chalk, the road bends
considerably to the west, in order to take advantage of a
more favourable surface.LONDON TO WORTHING.
23
ROAD FROM LONDON TO WORTHING.
This road diverges from the Sutton road last described,
at Tooting, and passes by Merton-abbey, Mitcham, and
Morden; thence in a straight line nearly to Ewell, then
through Ewell and Epsom, Ashtead and Leatherhead.
Here it enters the celebrated vale of Mickleham, and passes
up the valley of the Mole, through the village of Mickle-
ham, by Burford-bridge, to Dorking. Then it proceeds
through the weaiden country, over Holmwood-common, by
Capel and Warnham, to Horsham. Erom this place it goes
on to "West Grinstead, and at Storrington intersects the
chalk of the South Downs, passing through a deep cutting,
and then descending to Worthing. About a mile south of
Tooting this road makes an extraordinary bend to the west-
ward, whereby in a single mile the length is increased to
the extent of thirty chains. This bend was probably madje
to avoid the grounds of Merton-abbey, and probably because
the straight line would pass across a swampy, imperfectly-
drained tract of ground, bordering the Wandle, from Mit-
cham to Temer’s-bridge. This land is now, however, in a
widely different condition, being in a state of high cultiva-
tion ; and, upon the whole, there does not appear to exist
any obstacle to straightening the road at this part, so as to
effect a saving of thirty chains, or three-eighths of a mile,
in distance. Erom the village of Mitcham, the road is
nearly straight to Ewell, at a little more than thirteen
miles from London. In this part, the road passes over a
clay and gravelly district lying on the chalk, which is easily
reached, between Ewell and Mitcham, by boring a few feet,
or yards, in depth. Erom Ewell to Epsom the road is just
on the verge of the chalk country, and half a mile beyond
Epsom it passes over the common of that name, which,
being rather high ground, consists, for a considerable depth,
of clay. Then it passes on to Ashtead, between which and
Leatherhead it again intersects the chalk. At Leatherhead
the road turns nearly at right angles, and pursues a
southerly direction along the valley of the Mole.
This river, the principal streams of which rise on the
north sides of Tilgate and St. Leonard’ s-forest, after inter-
secting the weaiden country in a very circuitous direction,
and receiving -innumerable small tributaries, which flow
into it from every point of the compass, penetrates the
green-sand range in an oblique, north-westerly direction,24
ROAD-MAKING.
near Betchworth, and flowing round the grounds of Betch-
worth-castle and under Box-hill, assumes a northerly direc-
tion, and completely passes through the chalk by Burford-
bridge, and winding round Norbury-park, passes on to
Leatherhead, and so on, by Stoke d’Abemon, Cobham, and
Esher, into the Thames at East Moulsey.
The vale of Mickleham is probably, with the exception of
the gap at Guildford, the most favourable of all the passes
through the range of the North Downs chalk-hills. Of
course those passes through which rivers flow are superior
to those mere depressions in which no river or stream has
its course. Premising this, the only passes east of Dork-
ing are those of the Darent, which goes through the chalk
north of Sevenoaks, and the Medway, which goes through
Maidstone northward, to Bochester and Chatham.
Now both these latter are much inferior to the Dorking
pass, because opposite to each is a very high part of the
green-sand range, which opposes the carrying of a road or
railroad through them, except in a very circuitous direction.
Thus the Darent, which flows northward from Sevenoaks,
nowhere penetrates the green-sand, the whole of which
range at the south of Sevenoaks, and for miles on each
side, is very high, and presents formidable difficulties. The
Medway again penetrates the green-sand about five miles
west of Maidstone, which makes this passage out of the
question for roads going to the south or south-east, which,
accordingly, cross the green-sand where there is no gap at
all. Erom these considerations it follows that the Dorking
gap is the most favourable of all those lying to the east of
it, while on the west side there is only the Guildford, which
is under nearly similar circumstances.
Between Leatherhead and Dorking the road does not
follow the windings of the river, but adopts a tolerably
straight course, yet has no inclinations of such steepness as
to render any deviation desirable. In passing through the
town of Dorking, the road is deflected about half a mile
further to the west, and then proceeds to Holmwood-
common, where it passes over the greemsand range at a
spot where it is much depressed, and proceeds on, as before
described, through Capel and 'W’amham, to Horsham.
ROADS TO GUILDFORD.
Oxtb road from London to Guildford follows the same
course as the last described, as far as Leatherhead, and inBO ADS TO 0UILDFOBD.
25
fact continues that road in a straight line through the
town, where it crosses the river Mole, and proceeds by
Great Bookham, Effingham, West Horsley, East and West
Clandon, and Merrow, to Guildford. The other road passes
out of London, through Battersea and Wandsworth, goes
over Putney-heath, skirts the south-east side of Richmond-
park, passes over Kingston-hill, and so down into Kingston.
After passing through the town for three-quarters of a mile,
nearly in a westerly direction, it proceeds close alongside
the river Thames for nearly two miles, then goes over
Ditton-marsh, and through the village of Esher. It then
skirts the west side of Claremont-park, goes on to Cobham-
street, passes over Cobham-common and Wisby-common,
and goes on by Ripley, Threefords, and Gasding-hill, to the
east side of Stoke-place park, and on to Guildford, which it
enters at the same spot as the road from Leatherhead. The
distance from London to Guildford by the first of these
roads, namely, that through Epsom and Leatherhead, is
thirty-two miles, and by the other, or the Kingston road,
the distance is twenty-nine miles.
The Leatherhead road, in its passage from Leatherhead
to Guildford, passes over the chalk country in a more*
oblique direction than any of those we have before con-
sidered. Both these towns may be taken to be situate on
the chalk, Guildford being about ten and a half miles west
of Leatherhead, and four miles south of it; and the road we
are now examining connects the two places by forming the
hypothenuse of a right-angled triangle, whose base and
perpendicular are respectively ten and a half and four miles.
It lies nearly at the head of the water-bearing valleys
which open from the chalk of this district, and range in a
northerly direction, and as it approaches Guildford almost
defines the head or summit of the highest combes.
It is scarcely necessary to observe that the Thames is
the general drain of all this district, and receives into its
ample stream all the water rising from this as from every
other part of the North Downs; but the secondary rivers,
which more immediately drain the section of chalk country
between Leatherhead and Guildford, are the Wey and the
Mole; and one or other of these rivers receives all the
Small tributaries which flow down the eombes of the chalk.
It is obvious that a road in the situation of the one here
described, alternately intersecting the hollows in the chalk
surface and the ridges which separate those hollows, in26
EOAD-MAKING.
order to be, the most perfect in its levels, should assume a
wavy or bending direction, approaching the summit of the
chalk range in crossing the hollows, and receding from it in
crossing the ridges. This is, in fact, a similar case to that
of a road passing up the actual valley of a river, and cross-
ing alternately to tributary streams and the ridges which
separate them. This mode of laying out has obviously not
been followed in all cases in the road before us, but it is
unnecessary to point out that it always ought to be followed
where circumstances of another nature do not imperatively
require an opposite course.
The second, or more direct road to Guildford, passes at
first over a flat country, through Lambeth, Battersea, and
Wandsworth, seven miles from London, being nearly on
the extreme western verge of the district already described
as drained by the Bavensbourne and the Wandle. At
Wandsworth the road begins to rise, passing over the
north-west comer of Wimbledon-park, and attaining its
summit on Putney-heath. It then descends to cross a
small stream which rises on the chalk at Cheam, flowing by
Pylford-bridge and Combe-bridge, forming successively, but
on alternate sides, the boundary of Wimbledon-common
and Richmond-park, and continuing by Peace-bridge at
East Sheen, and falling into the Thames on the east side of
Barnes.
Beyond this stream, which is crossed at Bayeley-bridge,
the road goes along the south-east side of Richmond-park,
passes over some high ground called Kingston-hill, and
enters the town of Kingston at the east end. After pass-
ing through the town in a westerly direction, for rather
more than half a mile, it diverges from it at the west end,
and proceeds for a mile alongside the river Thames as far
as Thames Litton, where the Thames bends to the north-
east, while the road pursues the same south-westerly direc-
tion as before. Prom Thames Litton to Cobham the road
may be described as lying in the valley of the river Mole,
being nowhere more than a mile distant from that stream,
and often approaching more nearly to it. The surface of
this district is thrown into irregular shapes by numerous
elevations, sometimes appearing as continuous ridges, and
at other times mere conical hills—consisting of fresh-water
sands deposited on the London clay, and ranked by geolo-
gists of contemporaneous age with the extensive sands of
Bagshot and Primley heaths. These numerous detachedBOADS TO GTTILDFOBD.
27
elevations of sand have probably been continuous over this
part of the country, but the formation has perhaps been
washed away, so as to present at the present day only the
form'of numerous isolated hills, ridges, and elevated plains.
This road, where it borders the Mole, passes over several of
these patches of sand, as at Esher, Claremont-park, Esher-
common, Old Common, near Cobham, &c. The road is
tolerably straight between Thames Ditton and Cobham, but
might probably be improved by sweeping through the valley
of the Mole in a more central direction, instead of keeping
so far on the east side of it, and this without any sacrifice
of distance.
Between Cobham and Eipley the road passes over the
sandy district of Cobham-common, Ked-hill, and Wesley-
common, which divides the river Mole from a branch of the
Wey that flows into it at Ockham-mill, and in fact forms
also the water-shed between the two main streams. Imme-
diately south of Cobham there is a remarkable deviation
made in the straight direction of the road, by which, in a
length of two miles, an increase of distance is made of
nearly half a mile. Thus, instead of passing from Cobham-
street by the side of the Mole, and crossing it at a point
due west of Cobham-court, and shortly after entering Ock-
ham-common a little north of Catley-farm, and then ranging
in a straight line for Bodystone-hill, the road suddenly turns
to the north-west at Cobham-street, immediately crosses the
Mole, and passing round Pains-hill-park goe.s over Common
and Bed-hill, where it again bends into a more southerly
direction, and joins the straight line just described a little
north of Bodystone-hill.
This serious injury to the road appears to have been
inflicted to suit the convenience of the owners of several
parks and superior mansions situate around the borders of
the commons and in the valley of the Mole. Beyond Bip-
ley the road encounters no more of the sand-ridges before
spoken of, and passes gradually off the clay on to a country
where the chalk is near the surface. Prom Bipley to Guild-
ford the road occupies the valley of the Wey, is tolerably
direct in its course, and no improvement of any consequence
suggests itself.
The two main roads from the metropolis which have been
described as meeting at Guildford, there separate and di-
verge in various directions. First, there is the Famham
road, which passes in a singular manner along the very
b 228
HO AD-MAKING.
highest ridge of the chalk, along the actual axis of the
Hogsback, having of course a serious ascent to encounter
in emerging from the level of the Wey at Guildford, and
an equally serious descent from the chalk, about two miles
east of Eamham. This road then goes on by Alton to
Winchester and Southampton, while another branch of it,
diverging at Alton, passes by West Meon and Droxford,
down to Fareham and Gosport. Secondly, the Godaiming
road passes nearly south, and there diverges into three
branches, one of which passes by Bramshot and Petersfield,
down to Portsmouth; another goes through Haslemere and
Midhurst to Chichester and Selsea Bill, while the third goes
to Petworth, and there sends off one branch to Chichester
and another to Arundel. The third road out of Guildford
is the Wonersh-road, which passes on through Aldfeld and
Pulborough to Arundel, Littlehampton, and Worthing.
THE STAINES, OR GREAT WESTERN ROAD.
Of all the roads which pass out of London, the Staines
road is the most level, and with one exception the straight-
est. In the days of coaching, before the introduction of
railways, this road was remarkable for the vast amount of
traffic which passed, and this notwithstanding it only formed
one of the routes to Beading, Bristol, and the West of
England; most of the coaches at that time going to Bead-
ing by Colnbrook and Maidenhead, which, although a longer
road, possesses a much larger population than that which
adjoins the Staines road. The traffic, however, is still very
great on the first eight miles out of London, namely, as far
as Brentford; the whole of this space being at all times
covered by innumerable light vehicles, mixed up with heavy
traffic of almost every description.
This Staines road occupies an entirely different district
from those we have latterly been considering on the south
side of the metropolis. These have generally passed over
a high clay district, which appears in far distant ages, long
before our mundane chronology attempts to record events,
to have withstood the rush of waters which have excavated
the valley of the Thames. Opposed to these, on the north
side of the Thames, we have the high ground of Hampstead,
Highgate, and part of Hornsey, where the fresh-water sands
—a much more recent deposit than the clays of the south—
have not been denuded, but have either formed the banksTHE STAINES, OB 0BEAT WESTEBN BO AH.
29
of the estuary or islands which have never been submerged
beneath its waters. Supposing these sands on the north
side to have bounded the estuary, we find its breadth, from
Battersea to the foot of Hampstead-hill, to have been about
five miles; from Upper Holloway to the rise of Brixton-
hill, about six miles; from the rise of Epping-forest to
Greenwich, about four miles and a half, and so'on, the
breadth varying for some distance from four to six miles.
Although the channel is thus contracted eastward of Lon-
don, there seems on the west side to have been a great
expansion; for, while on the south the boundary appears
to have been the high lands which nearly follow the cir-
cuitous course of the river from Windsor by Staines, Chert-
sey, and Kingston, the northern boundary seems to have
swelled out wider and wider by Uxbridge, Buislip, Pinner,
by Stanmore, Highwood-hill and Southgate, and then to
have trended southward by the side of that high tract which
bounds the Lea on the east side. According to this view,
Harrow-on-the-Hill and the sand-hills of Hampstead and
Highgate w<)uld have been islands in this great lagoon,
whose waters would sweep round and enclose them; but
whether those solitary hills now standing, and composed of
clay, were submerged or not, is difficult to say. With
respect to the sand-hills, it is clear they have never been
submerged.
The road we have now to speak of lies entirely within
this ancient lagoon, the breadth of which, from north to
south, say from Pinner to Chertsey, was not less than fifteen
miles; and it lies" so clear of all high lands and supposed
ancient islands, that it is almost a perfect leveJ the whole
way from London to Staines. This road passes out of
London by Piccadilly and Hyde-park-comer, and proceed-
ing along the south side of Hyde-park and Kensington-
gardens, passes through Kensington, Hammersmith, and
Turnham-green to Brentford, and throughout all this dis-
tance of eight miles, is lined by an almost uninterrupted
succession of houses. From Brentford the road proceeds
in a straight line through Hounslow and East Bedfont on
to Staines, a distance of sixteen and a half miles from Hyde-
park-comer. Throughout this distance, with the exception
of some slight bends at Kensington, Hammersmith, and
Brentford, the road is practically a straight line.
It has already been stated that this part of the road lies30
BO AD-MAKING.
entirely in tlie London clay, and is nearly a dead level
throughout; we have now, therefore, to examine its exten-
sions beyond Staines. In the first place, there are two
roads from Staines to Beading, which we shall distinguish
by the terms “ Upper” and “ Lower” road; these two unite
into one a little beyond Wokingham, and form the original
old great western road through Newbury, Hungerford, and
Marlborough to Bath and BristoL Second, there is the
Bagshot road, which divides at Golden-farmer-hill, a little
beyond Bagshot, into two branches, one of which goes down
to Famham, where it unites with one of the roads already
described as leading from Guildford through Famham,
Alton, and West Meon, down to Gosport; while the other
diverges in a more westerly direction to Basingstoke, Win-
chester, and Southampton; and at the former of these
towns a still more westerly branch leads off to Salisbury,
Exeter, and Plymouth, forming the great road into Devon-
shire and Cornwall.
The upper road to Beading passes through the village
of Egham, and immediately begins to rise up to the high
ground forming Windsor-park, which is one of those exten-
sive and elevated ridges of sand which we have seen pre-
vailing so extensively m the neighbourhood of the roads to
Guildford. This road continues to rise for more than two
miles, before it attains the general level of Windsor Great
Park, at this spot, which is a little, but not much, lower than
the very highest part. . It bends considerably towards the
north in going through the Park, and intersects the sources
of several small streams which flow in a northerly direction
into the Thames. Its course through the Park may be
defined by the following points:—Bishop’ s-gate, Park-place,
Snow-hill, where the long walk terminates, Watch-oak, near
which it crosses the Queen’s-walk, and Holly-grove. It
then skirts the north-west side of Cranboum-wood, and, at
seven miles distance from Staines, turns at right angles into
a westerly direction, and passes over Lovel-hiU by the north
side of Ascot*place-park, then on to Winkfield and Maiden-
green, where it suddenly turns again at right angles into a
nearly southerly direction, and passes on to Haley-green
and Newell-green, turning gradually into the proper or
westerly direction, passing over Cabbage-hill, south of Bin-
field-park, on to Tippen’s-hill. Then it goes south of Ash-
ridge-wood, and shortly after bends into a south-westerlyTHE STAINES, OE GREAT WESTERN ROAD.
31
direction by Toutley-hall on to Toutley-common, where it
joins the lower road to Beading, at the distance of seven
miles from that place.
The lower road to Beading, although much more level
than the upper, is precisely the same length, the distance
from London to Beading by each road being about forty
and a quarter miles. After leaving the village of Egham,
the lower road ascends Egham-hill, and proceeds by Wick-
lodge and the Wheatsheaf, down to Cascade-bridge, where
it touches the comer of Virginia-water, and crosses a small
stream which rises from the sandy strata of Bagshot-heath,
Sunning-hill, Ascot and Windsor-forest, and flows into the
Thames below Chertsey. Just beyond Cascade-bridge the
Beading road separates from the Bagshot road at twenty-
one miles from London, the former taking a westerly direc-
tion, and the latter pointing nearly to the south-west. Erom
the twenty-first mile, the road proceeds along the south side
of Windsor-park through Blacknest and on to Sunning-hill.
It then proceeds in a straight line for nearly three miles,
passing by Sunning-hill wells, the south side of Ascot race-
course, Englemoor-pond, and Martius, soon after which it
curves to the north at the crossing of Bullbrook, when it
appears, from the shape of this part of the country, it
should curve to the south to cross the brook higher up,
and proceeds through the village of Bracknal across Priest-
wood-common, and on to a place called Golden Acorn.
Here the road makes a sudden bend to the south-west, and
goes on to Erognall-green, when it bends into a direction
north of west, and soon after enters Wokingham. In the
town of Wokingham the road makes two bends in opposite
directions, then proceeds in a tolerably straight course to
Beading.
It appears that the levels of this road might be materially
improved between Wokingham and the twenty-seventh
mile, a distance of four miles, the twenty-seventh mile
being at the western extremity of that straight part which
has been already described as commencing at Sunning-hill.
This improvement would also effect a saving of distance equal
to half a mile in a length of four miles. This road, as far
district the London clay scarcely appears, but the plastic
clay is extensively developed between Wokingham and
Beading.32
BOAD-MAKIKG.
The Bagshot read for four and a half miles beyond Starnes,
namely, to the twenty-first mile, is identical with the road
last described. It then proceeds by Shrubs-hill and Broom-
hill-hut, over Bagshot-heath by Bagshot-park into the
town of Bagshot. It then goes on by (xolden-farmer-hill,
between Turf-hill and Crawley-hill on to Osnaburgh-hill,
near the Military College at Sandhurst, about a mile beyond
which, viz. at thirty and a half miles from London, it
crosses the Blackwater river, which joins the Loddon a
little south of Swallow-field, and flows into the Thames at
Wargrave, a little above Henley. Beyond the Blackwater,
the road proceeds over a farther succession of dreary wastes
and commons, the principal of which are Yateley-heath and
Hartford-bridge flats, and passes on through Winchfield
and Old Basing to Basingstoke. This road, for a distance
of fifteen miles, namely, from twenty-one to thirty-six miles
from London, passes almost entirely over dry sandy heaths,
in which little has even yet been done to induce cultivation.
A great part of this district is perfectly flat, the construc-
tion of the road has evidently cost very little, and it is
difficult to see where any improvement could be made
between Staines and Basingstoke.
The Farnham branch, which separates from the Bagshot-
road at Golden-farmer-hill, remains to be noticed. This
road proceeds in nearly a straight course to Frimley, where
it crosses the Blackwater about two miles higher than the
Basingstoke road last described; it then proceeds by Wind-
mill-hill to the west side of Farnborough-place-park, near
which the South-Western railway crosses it,theFamborough
station being fixed at the crossing of this road. Then the
road goes on over Aldershot-heath by Bagman’ s-castle,
crossing the Basingstoke canal at Bow-barge, and proceed-
ing by a place called West-end, touches the eastern extremity
of Hungary-hill, and descends by a rather circuitous course
to the town of Farnham, where, as already explained, it
joins the road from Guildford to Gosport. This road, like
the preceding, passes chiefly over a considerable tract of
sandy heath, very uninteresting and unvaried in its appear-
ance. Here and there large tracts in the neighbourhood of
the road have been planted with fir trees, which will in time
ameliorate the hard knotty soil, containing much unde-
composed fibrous vegetable matter, which forms the surface
of these heaths, while an abundant application of lime, by
decomposing and rotting this vegetable matter, will probablyTHE MAIDENHEAD BOAD.
33
in the course of a few years cause it to bear crops and to
be worth cultivation. Its course being tolerably straight,
no improvement suggests itself as to the mode in which the
road has been laid out.
THE MAIDENHEAD ROAD.
This is another of the roads leading from the metropolis
to Bath, Bristol, and the West of England; and as it joins
the Staines road at Reading, the extensions beyond that
place will apply equally to the road through Maidenhead;
it is remarkable also that the length by each road to Read-
ing is about the same. This road leaves the Staines road at
Hounslow, ten miles from London, and proceeds in a
straight direction to Cranford-bridge, where it crosses the
Yedding-brook, a circuitous stream which works several
flax-mills, powder-mills, and oil-mills, and flows into the
Thames at Isleworth. The road bends into a more westerly
direction at Cranford-bridge, and proceeds by Harlington-
corner and the Magpies to Longford, where it crosses, in
space of less than half a mile, three streams into which the
river Coin is here divided, and proceeds on to Colnbrook,
where, at seventeen miles from London, it crosses the main
stream of the Coin. Erom Colnbrook the road proceeds
in nearly a straight line to Slough, passes over Salt-hill, the
scene of Eton Montem, and on to Two-mile brook, where it
crosses a very small stream which flows into the Thames at
Boveney. Erom this point the road runs nearly straight
to Maidenhead, twenty-six miles from London, after pass-
ing under the Great Western railway at the twenty-fifth
mile, and a little further on passing over the river Thames.
With the exception of the slight rise at Salt-hill, imme-
diately beyond Slough, the whole length of this road from
London to Maidenhead may he considered a practical level;
it lies for the whole distance in the valley of the river
Thames, in a flat, open, and probably diluvial district of
country, almost entirely devoid of irregularity. This road
is superior to the Staines Great Western road, inasmuch as
on that road the low flat country ceases at Egham, eighteen
miles from London, whereas the low flat country continues
on the other road to Maidenhead itself, twenty-six miles
from London. Beyond Maidenhead the road forms a sort
of bow, bending to the north between that place and Twy-
ford, thirty-four miles from London, which has the effect of
B 334
BOAD-MAKIHG.
throwing it into irregular ground at Yines-hill, Stubbing’s-
heath, Knowl-hill, and other places, where the road skirts
an elevated chalk country, which lies between itself and the
river Thames, which here makes a great detowr to the
north. The Great Western railway, between Maidenhead
and Twyford, is a straight line, and the levels of the road
would also be improved by adopting the same course. At
Twyford, the road is on a comparatively low level, as it here
crosses the river Loddon, at less than two miles from War-
grave, where it joins the Thames. The road continues
through a flat district of country from Twyford to Heading.
In addition to the traffic passing through Maidenhead to
Bath and Bristol, this place formed also a point on the
main road through Lechlade and Cirencester to Gloucester
and Cheltenham, and the greater part of South Wales.
Some of the coaches also to Oxford, and even Birmingham,
passed this Way, allured into the more circuitous road by
the hope of passengers who did not possess the advantage
of being located on the great Holyhead road.
THE OXFORD ROAD THROUGH UXBRIDGE.
This road leaves London on the north side of Hyde-park
and Kensington, keeping parallel to the Staines road as far
as Shepherd’ s-bush, nearly three miles from London. It
there diverges into a northerly direction, and passes on, by
Acton and Ealing-common, to the north side of the village
of Ealing, where the Great Western railway almost touches
it. The road then runs parallel to the railway, as far as
Hanwell, and passes under it a little further on, namely, at
eight and a half miles from London. It then passes on
through Southall, over the Paddington canal, at ten and a
half miles, by the Adam and Eve and Hayes-end, to Hil-
lingdon. Here it makes a considerable curve to the south-
west, to avoid the grounds of Hillingdon-house, and soon
after enters Uxbridge, fifteen miles from London. Beyond
Uxbridge, it crosses the Grand Junction canal and the river
Coin, and continues in a straight course, by Ivy-house, to
the west side of the village of Denham, where it bends into
a more westerly direction, and proceeds, by Pinnington and
Woodhill-farm, to Gerard’s-cross-common, a high and open
part of the country. Leaving Gerard’s-cross, the road pro-
ceeds in a tolerably straight course to Beaconsfield, passing
on the north side of Bulstrode-park, and south of Wilton-THE OXFORD ROAD THROUGH UXBRIDGE.
35
park, through a high district of country. Beaconsfield is
twenty-three miles from London, and the road proceeds
from this place in a westerly direction to Holtspur-heath,
immediately beyond which it descends rapidly into the val-
ley of the Loudwater, a stream of short extent, but of
great commercial importance, from the great number of
valuable mills it works. This stream rises from the chalk
beyond West Wycombe, flows down a deep valley in a
south-easterly direction, sweeps round Wobum-hill, and falls
into the Thames half a mile above Cookham. The road
proceeds up the valley of this stream, keeping on the east
Bide of it, and passing through the village of Loudwater
by Wycombe-marsh and Basonbury to High Wycombe.
It then continues, still on the east side of the Loud-
water stream, for two miles in a straight line to West
Wycombe, passing north of West Wycombe house, a little
beyond which it leaves the valley, and bends to the south-
west. It then passes by Mice-farm and St. Andrew’s, and,
bending again, assumes its former north-westerly direction,
and goes on, by Ham-farm, the Hut, and Beacon’s-bottom,
to Stockenham-common, whence it proceeds, through Tets-
worth, Rycote, and Wheatley, to Oxford. This road, as far
as seventeen miles from London, or about two miles beyond
Uxbridge, passes through a flat district of clay, containing
some few ridges and irregularities, but not materially vary-
ing in its character from that adjacent to the Staines and
Colnbrook roads. There is a slight rise at Kensington and
Notting-hill, another at Acton, and also at Hillingdon, near
Uxbridge. With these exceptions, this first part of the
road is tolerably level till it rises on to Red-hill, imme-
diately beyond Denham. Prom this place to some distance
beyond West Wycombe, say from seventeen miles to about
thirty-five, the road may be considered to pass over a chalk
district, because, although the ridges between the valleys
frequently consist of clay or gravel, and sometimes of sand,
these are mere patches resting on the chalk, and have gene-
rally been denuded from the valleys in which the chalk is
exposed. Thus gravel, clay, and sand, are all met with in
the furrowed, broken, and irregular country between Ux-
bridge and the valley of the Loudwater. In this part of
the country, it is very common to find the operations of
brick or tile-making and lime-burning carried on in the
same plot of ground ; the clay being dug from immediately
below the surface, while the chalk for burning into lime is36
ROAD-MAKIUGk
procured from a shaft sunk through the clay, varying from
a few feet to sixty or seventy feet in depth. The chalk is
exposed on each side of the Loudwater valley, as far as West
Wycombe. The main continuation of this road beyond
Oxford goes on through Witney, Burford, and Northleach,
to Cheltenham, Gloucester, and Tewkesbury; while roads
branch off from one or other of those towns to most parts
of Herefordshire, Monmouthshire, and the southern counties
of Wales. Another important road from Oxford passes
through Woodstock, Enstone, Shipston, and Stratford-on-
Avon, and thence, through Henley-in-Arden, to Birmingham.
ROADS TO AMERSHAM AND AYLESBURY.
The most direct road to Amersham branches out of the
Oxford road last described, about a mile beyond Denham,
or eighteen miles from London, and proceeds up the valley
of the Misboum stream, which rises from the chalk about
a mile beyond Great Missenden, and flows into the Coin a
little above Uxbridge. On leaving the Oxford road, the
Amersham road rapidly descends into the Misbourn valley,
and passing by Oak-end, and on the west side of Chaifont-
park, goes on to Chaifont St. Peter, where it crosses the
stream, passing over to the east side of it. Thence it con-
tinues, by Gravel-hill, Water-hall, and Stoneage-pheasant,
opposite to Chaifont St. Giles, which is on the west side of
the stream. The road then proceeds, still on the east side
of the valley, by New-house, the Hut, Harwood-downs,
&c., on to Amersham ; just before coming to which it again
crosses the stream. This road, with the exception of the
abrupt descent on leaving the Oxford road, appears to be
judiciously laid out in its progress up the valley; and even
this descent it would be difficult to avoid without making
an additional line of road, and so joining the Oxford road
at the foot of Bed-hill, which is little above the level of the
* stream opposite Denham.
The other road to Amersham is a mile longer than the
one just described, and passes over a much more irregular
country. It leaves London by the well-known Harrow-
road, which may be viewed as a continuation of the City-
road and New-road, and, passing through Paddington in
rather a crooked direction, crosses the Paddington canal near
Westbourne-green, and proceeds on the north-east side of
the canal by Kensal-green, bounding there the cemetery ofROADS TO AMERSHAM AND AYLESBURY.
37
that name, and crossing at the comer of the cemetery the
London and North-Western railway, which here passes
under an archway, and where the road is carried over, at
the same time that it extends under a corner of the ceme-
tery which it was necessary to preserve intact. The road
then passes on over Honeypot-hill, by Holsden-green,
near Greenhill-house, opposite which it begins to descend
Honeypot-hill, which it never ought to have ascended,
and could very easily have avoided. At five miles from
London commences the descent, by the road suddenly
bending at right angles to the south, from which point it
twists round again into its proper direction, till on crossing
the Brent near the sixth mile, it again attains the north-
westerly course. Before reaching the seventh mile, however,
that is, when just opposite Wembly-park, it again totally alters
its direction, proceeding to the eighth mile in a course rather
south of west,there again changes,pointing now nearly to the
north; and after several other bends, curves, and irregular
unmeaning gyrations, mounts right up into the High-street
of Harrow-on-the-hill. Having attained this elevation,
which is a mere isolated ridge, about three miles in length,
by an average breadth of a mile and a half, and which sends
off streams from innumerable points all round its circum-
ference, the road proceeds along it in the longest direction,
and having completely passed through the village of Har-
row, descends at the north end of it. The road then
proceeds, through the same infinite variety of twists and
bends, to Hooking-green and Pinner, which is probably one
of the most crooked and irregular villages in England. Be-
yond Pinner, the road proceeds over Pinner-green, in a
north-westerly direction, to Batchworth-heath, a little more
than sixteen miles from London. It then passes for a mile
and a half on the south-west side of Moor-park, and, cross-
ing the river Coin and Grand Junction canal, arrives at
Rickmansworth. Thence it passes on the west side of
Bickmansworth-park, which separates it from the valley of
the Chess, and then on to the north side of Chorley-wood
common. It then passes on to Green-street, where it
bends into a westerly direction; is parallel to the Chess,
and within half a mile of it, for a distance of a mile and a
half, when it twists in several directions, and goes on to
Loudhams, within two miles and a half of Amersham. At
Loudhams the road assumes nearly a westerly direction,
passing on the north side of Beel-house. Then, within one38
BOAD-MAKING.
mile of Amersham, it bends at right angles into a southern
direction, and joins the Uxbridge-road to Amersham about
half a mile before entering the town. The two roads being
here united into one, it continues through the town of
Amersham, and proceeds still in the Misbourn valley, pass-
ing by Little Missenden and Great Missenden, and then on
to Windover, through an open gap in the chalk, and so,
with no great variation, to Aylesbury.
This road, between London and Amersham, although
about the same length, or perhaps a little longer than the
road by Uxbridge, ought to be much shorter, its general
direction being much straighter, Harrow and Pinner being
actually in the straight lme between London and Amer-
sham, and Eickmansworth not more than two miles north
of the straight line. On the other hand, the road by Han-
well, Uxbridge, and Chalfont St. Peter, is a complete bow or
arc ; the first of these places being four miles, Uxbridge be-
ing five miles, and Chalfont St. Peter being two miles out of
a straight line drawn from Amersham to Cumberland-gate*
Hyde-park. The reason, then, of the road being much the
straightest in general direction is to be sought for in the in-
numerable short bends and twists which have been noticed in
describing its general course. Pirst, there are the various
bends which it makes in going over Honeypot-hill, and the
bend at Wembly-park. These might all be avoided, with all
the irregularity of ground which the bending, after all, does
not appear designed to meet; and, at the same time, half a
mile of distance may be saved in four miles of road, by
bending it at the corner of Kensal-green cemetery, so as
not to cross the railway at all, and carrying it between the
railway and the Paddington canal, as far as Apperton,
thence sweeping round by a great curve into the present
road at the Swan. With respect to the passage over Har-
row-hill, this of course is not to be avoided, except at the
expense of sacrificing the convenience of the town, which
is probably not to be overlooked. It certainly does seem,
however, that a more direct course might be taken on leav-
ing Harrow ; that between that point and Pinner the road
might be shortened; and, particularly at Pinner, that it
might be very much improved. Prom Harrow to Pinner,
and indeed nearly as far as Eickmansworth, the road passes
over a high country, which although geographically con-
sidered as part of the valley of the Thames, yet has lost its
valley character, and become the summit from which flowTHE ST. ALBAN’S BO AD.
39
the feeders of the Yedding-brook and the river Coin. The
road might be somewhat shortened by removing objection-
able bends between Pinner and Rickmansworth, but perhaps
not materially improved in its levels. Prom Rickmans-
worth the road passes on for nearly seven miles in a tolerably
easy country, which may be termed the valley of the Chess,
a stream which rises a little beyond Chesham, and flows
through the chalk, by Flaunden and Chenies, to Rickmans-
worth, where it joins the river Coin. A part of the road
between Rickmansworth and Amersham may be greatly
improved, and at the same time shortened, by avoiding that
great bend which has been before described, at one mile
from Amersham. The road should turn off at Loudhams,
two and a half miles from Amersham, and curve gradually
round into a westerly direction, until it joins the TJxbridge-
road at the same point as at present. Thus it would have
a much more gradual fall into the valley of the Misboum
than the existing road, and would be fully half a mile
shorter in a distance of little more than two miles. The
extensions of this road beyond Aylesbury go on in one
direction, through Bicester, Enstone, Chipping Norton,
Moreton-in-the-Marsh, Broadway, and Evesham, to Wor-
cester, and thence to Leominster, Tenbury, and Bewdley,
also to Aberystwith and the central counties of Wales.
Another road from Aylesbury leads on, through Bucking-
ham and Banbury, to Stratford, Warwick, Coventry, and
Birmingham.
THE ST. ALBAN'S ROAD.
The road to St. Alban’s through Edgeware possesses
some interest, because it is the shortest route to St. Alban’s
and a host of places beyond, and because there is abundant
evidence of its having been the work of the Romans, whose
skill and sagacity it very strikingly exhibits. It leaves
London at Cumberland-gate, and proceeds through Pad-
dington, in one undeviating straight line, as far as Brockley-
hill, a distance of more than ten miles from Cumberland-
gate. k It passes over what is now called Maida-hill, a
sloping tract of ground lying west of the Regent’s-park,
and proceeds by Kilburn-priory on to Kilbum-wells, where
it crosses over the London and North-Western railway.
It then proceeds through Kilburn-vale, one of those hollows
leading up to the side of Hampstead-hill, and passes on by40
BOAD-MAKING.
Shoot-up-"hill to the Slade and Lower Oxgate farm. Shoot-
up-hill is separated by a depression from the elevated slope
of Hampstead-hill, and through this depression the road
passes. The Slade and Lower Oxgate farm mark two
sources of the river Brent, indicating the road to be still
on comparatively high ground. The road then goes on to
cross other feeders of the Brent, having their sources higher
up in the country towards Eryern Barnet and Whetstone,
passes near a few houses called the Hyde, then adopts the
valley of one of the principal feeders of the Brent, which
rises beyoud Edgware, in fact from the side of Brockley-hill.
The road passes through the long street of Edgware and
Little Stanmore, and ascends to the summit of Brockley-
hill, where was fixed the famous station called Sullonicce.
The road then bends somewhat out of its direction, and
crosses over an intermediate depression to Elstree-hill,
which is only a mile distant from Brockley-hill. At the
end of the village of Elstree, the road takes another bend in
the direction of St. Alban’s, and proceeds in another per-
fectly straight line to St. Stephen’s, one mile from the
centre of the town. Beyond Elstree the road passes by
Medburn, and then proceeds nearly to St. Stephen’s, in the
valley of a branch of the Coin, which branch rises from
several sources springing from the high ground of Elstree,
Brockley-hill, and the neighbourhood. It passes on the
west side of Kendal-hall, west of Aldenham-lodge, by
Colney-street and Park-street, where it crosses the Coin
itself, and then over two small rises in the ground to St.
Stephen’s. Erom this point the ancient road probably
went on still in a straight line to Verulam, the Homan
name for St. Alban’s, but now more particularly applied to
a part situate on the stream of the Coin, westward of the
town. To the part now called Verulam the straight road
from Elstree to St. Stephen’s directly points, but the pre-
sent road bends at St. Stephen’s, and after again crossing
the Coin, rises rather abruptly into the centre of the
town.
The levels of this road are favourable, as it keeps a suf-
ficient distance from the high ground on the western side
of Hampstead to avoid its irregularity. About two miles
further on it begins to ascend, and continues gradually to
the summit of the country at Brockley-hill. The road here
bends to Elstree-hill, obviously for military purposes, and
then gradually descends a valley leading into the Coin,THE GREAT HOLYHEAD ROAD THROUGH BARNET. 41
about a mile and a half south of St. Stephen’s. A modem
engineer would probably see no reason to alter this road
anywhere except at the summit, which he would probably
cross between Brockley-hill and Elstree, in a north-westerly
direction, taking on each side the hollows of the two
streams, which flow on opposite sides and in opposite direc-
tions. On the south side of this crossing he would carry
the road in a straight line nearly in the valley of the
stream, to join the present road somewhere about Edge-
ware, and on the north side would pass close to the reser-
voir, and fall into the present road half a mile north of
Medburn.
THE GREAT HOLYHEAD ROAD THROUGH BARNET.
This was one of the most celebrated of all the roads out
of London, as it carried nearly all the traffic between the
metropolis and Liverpool, Manchester and Birmingham,
besides being the great highway to Ireland, by way of
Chester and Holyhead. It is still under the management
and direction of a parliamentary board, termed the Com-
missioners of the London and Holyhead road; with a
competent staff of officers and assistants, including an
engineer, who reports annually on the state of the whole
road.
Like all other turnpike roads, it is, nevertheless, divided
into trusts ; and the trustees of each district appoint their
own surveyor, and exercise a local management of the
repairs, &c.; but when any improvements are to be made,
these are executed under the control of the parliamentary
commissioners and their engineer.
This road, the most important probably in the kingdom
for purposes of mail-coach travelling, may be said to com-
mence at the General Post Office in St. Martin’s-le-Grand,
whence it passes by Goswell-street to the Angel at Isling-
ton, and thence through Islington to Holloway. The road
formerly ascended up Highgate-hill to the village of High-
gate, and descended on the other side to Abbot’s-farm; but
of late years a great improvement has been made by carry-
ing the road on the east side of Highgate, and making a
deep cutting through the hill. This has had the effect both
of straightening the road and greatly improving its levels.
After leaving Highgate, the road proceeds by Abbot’s-farm
and Brown’s-wefls, crossing near their source two small42
BO AD-M AKIN G.
feeders of the Brent, and then begins to ascend an elevated
ridge of country from which tributaries of the Brent rise
on one side, and those of the Lea on the other. The road
continues about a mile on this ridge, and then passes
through Whetstone. It then very gradually descends,
passing by Grreenhill-grove and the old Poor-house, a little
beyond the tenth mile from London. The ascent from the
fairfield up to Chipping Barnet was formerly very steep,
but of late years has been much improved by a very high
embankment, which fills up the hollow, and reduces the
inclination to about one in thirty. Passing through the
street of Barnet for rather more than a quarter of a mile,
the road bends suddenly to the left in the direction of St.
Alban’s, while the great north road goes straight through
the town in the direction of Hatfield. After leaving
Barnet, the Holyhead road proceeds on to the Green
Dragon, passing between Durham-park on the west, and
Wrotham-park, the seat of Mr. Byng, on the east side. It
then goes on by Laurel-lodge to South Mims, where a new
piece of road has been made to avoid a bend, and then
proceeds in a straight line to Badge-hill, where also the
old course of the road has been diverted, and a deep cutting
made through the hill. Prom Bidge-hill the road proceeds
to London Colney, where it crosses the river Coin, and
thence continues through a tolerably flat country to the
Mile-house, situate one mile from St. Alban’s. Prom this
place it ascends to and enters St. Alban’s on the east side
of the town. Prom St. Alban’s the road proceeds in a
northern direction through Harpenden, Luton, and Barton,
to Bedford; but this road was never much used by coaches
going northward from the metropolis, as they used the
road which leaves the present one at Barnet, and which
will be described next in order. By far the most impor-
tant road from St. Alban’s is the great Holyhead road,
which passes on through Dunstable, Hockliffe, Penny
Stratford, Stoney Stratford, Towcester, Weedon, Daventry,
Dunchurch, and Coventry, to Birmingham. Prom Bir-
mingham the great Holyhead road goes on by Wolver-
hampton and Market Drayton to Chester, and thence by
Conway and Bangor, across the Menai-bridge, and through
the Isle of Anglesea, to Holyhead*
A considerable section of the modem Holyhead road,
namely, from St. Alban’s to Weedon Beck, occupies the
site of the ancient Boman Watling-street, which went onTHE GREAT NORTH ROAD BY BARNET AND HATFIELD. 43
between Clifton and Crick to Wibtoft, near Lutterworth,
where it intersected the great Fosseway, another Homan
road, leading from Cirencester to Lincoln and York. It
then went on in a straight line to Atherstone, and thence
by Ensor and Fazeley, by Drayton Manor, near Tamworth.
Then it went on by Norton and Stretton to Weston and
Wellington, and so to Shrewsbury. The first part of the
Watling-street from London to St. Alban’s has been
already described; and as the Holyhead road first adopts
the old Homan road at St. Alban’s, the question naturally
arises, why was the first section of it from the metropolis
to St. Alban’s rejected in favour of the road by Barnet F
The levels of the Homan road are decidedly superior, the
distance from the Post Office to St. Alban’s about the
same by each road, while from the west end of London
the Homan is two miles shorter, being only nineteen miles,
while the other is twenty-one miles. The principal objec-
tions to the Barnet road are the ascent of the Highgate-
archway road,—which is still serious, notwithstanding the
improvements that have been made,—and the very steep
hill on the south side of Barnet. No convenience connected
with the peculiar department of the Post Office, such as the
delivery of mail-bags at the intermediate villages, could
have compelled the use of the Barnet road by the Holyhead,
Chester, and Liverpool mails, because the great northern
road, which of necessity passes through Barnet, was suffi-
cient to serve for their supply, while the villages between
Barnet and St. Alban’s are very insignificant, and could
have been supplied by foot-posts without any inconvenience.
It still remains, therefore, a matter of considerable sur-
prise, why the Barnet road was preferred to the Homan
road by Edgeware, not only by the mails, but by nearly
all the coaches which made use of the Holyhead road.
THE GREAT NORTH ROAD BY BARNET AND HATFIELD.
This road, as before explained, is identical with the
Holyhead road as far as Barnet. It goes on through the
long street of that place, and passes by Monken Hadley,
skirting for a mile and a half on the east side of Wrotham-
park, passing thence by Gar wick-corner to Potter’s-bar;
then on to Littleheath and Swanley-bar, on the east side of
Brockman-park, by Bell-bar and Woodside, whence it goes
on for a mile through Hatfield-park, the seat of the Mar-u
BO AD-M AKIN Gh
quis of Salisbury; then bends to the north, and skirts the
park on the west side as far as the town of Hatfield,
through the street of which the descent is very rapid, very
crooked, and dangerous. Beyond Hatfield the road goes
on by Welwyn and Hitchin to Shefford, Bedford, Higham
Ferrers, Kettering, Market Harborough, and Leicester.
Another branch, being in fact the great north road, goes
off at Welwyn through Baldock, St. Neot’s, Alconbury-
hill, Stilton, Stamford, Grantham, Newark, East Retford,
Bawtry, Doncaster to York, Leeds, Newcastle, Carlisle,
Edinburgh, and Glasgow, and all parts of Scotland. The
principal objection to this road near London, is the danger-
ous and inconvenient hill in the town of Hatfield. It is
singular that this has been allowed to exist so many years,
when the slightest observation of the natural drainage of
the country would at once point out how it might be
avoided. For a mile and a half before approaching Hat-
field, the valley in which the road ought to pass, here
distant about half a mile to the west, is distinctly visible.
As the Great Northern railway is to pass down this valley
for some miles, altogether on the west side of Hatfield-
park, an arrangement has been made, and an Act of Parlia-
ment obtained, for carrying the road alongside the railway
for several miles, by means of which the highly objection-
able hill in the town of Hatfield will be entirely avoided,
and the new piece of road will join the present one at the
lower and northern end of the town, where the ground is
quite flat. Many other objections might be taken, not
only to the rest of the road between Hatfield and St.
Alban’s, but to the whole of the road to London. It
appears, in fact, that the whole of the first fourteen miles,
namely, from London to Potter’s-bar, would be improved
by adopting the road now used by some of the Hatfield
coaches, by Ball’s pond, east of Hornsey, Southgate, be-
tween Beech hill and Trent-park, and joining the present
road at Potter’s-bar. This road is not longer than the
present turnpike road, which it entirely avoids. Highgate-
hill, and the summit corresponding with Bamet-hill, is
crossed under much more advantageous circumstances.RUDIMENTS
OP THB
ART OF CONSTRUCTING ROADS.
CHAPTER I.
THE EXPLOBATION OF BO ADS.
No surer indication can be afforded of the extent of a
country’s trade, or even of its advancement in civilisation,
than the existence of good and sufficient means of internal
communication: for since it is one of the wise dispensa-
tions of Providence that many of those commodities which
the present artificial state of society teaches us to regard as
necessaries, are very unequally distributed, some being
wanting in certain localities where again others are only
found, it becomes necessary, in order that all may be
equally well served, that an interchange of these commodi-
ties should take place, so that the whole country may par-
ticipate equally in the enjoyment and use of those things
Which would otherwise be confined to only certain districts.
Thus, we may have in one part of a country huge forests,
stocked with various kinds of timber; in another, extensive
tracts of fertile land, capable, if properly cultivated, of
yielding supplies of com and other produce, sufficient for
the support of a densely-populated country; in a third,
mineral treasures, coal and iron, or the more precious
metals; in another, stone, well adapted for the construction
Of houses, and for other building purposes: and yet, with
all these latent treasures dispersed throughout the country,
of what avail would they be, unless the means were pos-
sessed of conveying them to every part of the land, and46
THE EXPLORATION OP ROADS.
thus distributing to all what would otherwise be enjoyed
but by a few ?
It is not, however, only for the purposes of its own inter-
nal trade that good means of communication are required;
they become even more necessary, to ensure an extensive
commerce with foreign countries, to enable the peculiar
produce of the several districts to be brought together to
those parts of the coast which have been either naturally
or artificially formed into ports, and then again to distri-
bute to every part of the country the goods brought in
exchange from foreign lands, comprising frequently the
necessaries as well as the luxuries of human life.
And further, good means of internal communication are
essential for the proper defence of a country (whether island
or continental) against either the attacks of foreign aggres-
sors or civil tumults, rendering a much smaller standing
army necessary for this purpose than would otherwise be
required, and reducing one of the most costly and most
odious burdens which a civilised country can be subjected
to.
Such being the case, it will not be a matter of surprise
that, from the earliest periods, and in all nations having
any pretensions to civilisation, the establishment and im-
provement of the means of internal communication has
always been regarded as a consideration of primary im-
portance ; and one which has engaged the highest talents
of the civil engineer, the result of whose exertions devoted
to this object has been the perfection of common roads,
.railways, and canals.
It is not necessary to enter into the comparative merits
or advantages of these several means of communication, in
order to establish the importance and necessity of com-
mon roads. For although, under certain circumstances, it
might be questionable which of the three would be the best
adapted for serving the tract of country through which it
was to pass, there are an innumerable number of cases in
which only the common road could be advantageously em-
ployed. Railways and navigable rivers or canals may boTHE EXPLORATION OE ROADS.
47
regarded as the arteries of traffic; while common roads are
simply the veins or smaller ramifications through which the
means of conveyance are carried into every nook and comer
of the land. It would he quite impracticable so to inter-
sect any country with canals or railways as to obviate the
necessity of common roads, or to make the former univer-
sally supersede the latter.
The formation of a perfect general system of railway
communication necessitates the construction of several new
common roads, in order that towns situated at some dis-
tance from the nearest line of railway may fully participate
in the benefits to be derived from it.
We have been led into these remarks because many
might think that, since the general adoption of railways,
the construction of common roads had become of minor
importance, and was hardly worthy of much consideration;
whereas, in truth, they are in a great degree mutually de-
pendent upon each other, as regards their utility and suc-
cess. The present work is confined entirely to the art of
constructing common roads, in situations where none pre-
viously existed, and to the repair of those already made.
Before entering into the practical details of their con-
struction, it will be desirable to go into the subject of the
exploration of roads, or the manner in which a person should
proceed in exploring a tract of country for the purpose of
determining the best course for a road, and the principles
which should guide him in his final selection of the same.
Let us suppose that it is desired to form a road between
two distant towns, A and b, fig. 1, and let us, for the pre-
sent, neglect altogether the consideration of the physical
Fig. 1.
i>48	THE EXPLORATION OP ROAD 9,
features of tlie intervening country; assuming that it is
equally favourable, whatever line we select. Now, at first
sight, it would appear that, under such circumstances, a
perfectly straight line drawn from one town to the other
would be the best that could be chosen. On a more care-
fill examination, however, of the locality, we may find that
there is a third town, c, situated somewhat on one ride of
the straight line which we have drawn from A to b ; and,
although our primary object is to connect only the two
latter, that it would, nevertheless, be of considerable ser-
vice if the whole of the three towns were put into mutual
connection with each other. Now this may be effected in
three different ways; any one of which might, under cer-
tain circumstances, be the best. In the first place, we
might, as originally suggested, form a straight road from
a to b, and, in a similar manner, two other straight roads
from a to c, and from b to c, and this would be the most
perfect way of effecting the object in view; the distance
between any two of the towns being reduced to the least
possible. It would, however, be attended with considerable
expense, and it would be requisite to construct a much
greater length of road than according to the second plan,
which would be to form, as before, a straight road from a
to b, and from c to construct a road which should join the
former at a point d, so as to be perpendicular to it; the
traffic between a or b and c, would proceed to the point n,
* arid then turn off to o: with this arrangement, while the
length of the roads would be very materially decreased,
only a slight increase would be occasioned in the distance
between c and the other two towns. The third method
would be to form only the two roads a c and c B, in which
case the distance between A and b would be somewhat in-
creased, while that between a and c, or b and c, would be
diminished; the total length of road to be constructed
would also be lessened.
As a general rule it may be taken, that the last of these
methods is the best, and most convenient for the public;
that is to say, that if the physical character of the countryTHE EXPLORATION OF ROADS.
49
does not determine the course of the road, it will generally
be found best not to adopt a perfectly straight line, but to
vary the line so as to pass through all the principal towns
near its general course; for the reason, that the public may
be conveyed from town to town with greater facility and
less expense than if the straight line were adopted, and the
towns were merely made to communicate with it by means
of branch roads: since, with the first arrangement, any
vehicles established to convey passengers or goods between
the two terminal towns, would pass through all those which
were intermediate; while, if the straight line and branch-
road system were adopted, it would be requisite also to
have a system of branch coaches to meet the coaches on
the main line.
In laying out a road in an old country which has been
long inhabited, and in which the position of the various
towns, &c., requiring road accommodation is therefore al-
ready determined, we are left less at liberty in the choice
and selection of the line of road, and must be guided in
that choice by different considerations to those which would
determine the line of a road made through a new country,
where our only object was to establish the easiest and best
road between two distant stations. In the first case we
should take into consideration the position of the various
towns and other inhabited districts situated near the in-
tended road, and its course would be, to a certain extent,
controlled thereby; while, in the second case, we should
simply examine the physical characters of the country, and
base all our proceedings on the result.
Whichever of these two cases, however, may have to be
dealt with, in the ultimate selection and adoption of the
line of road between those points which are fixed by other
circumstances, the same careful examination of the physical
character of the country should be made, and the same
principles should control the choice.
In examining almost any tract of country, one of the first
points which must attract our notice is the unevenness or
undulations of its surface; but if we extend our observation
e50
THE EXPLORATION OP ROADS.
a little further, we shall perceive, even in the most appa-
rently irregular countries, the same general principle of
conformation. We shall find the country intersected in
various directions by rivers decreasing in size as they leave
their point of discharge; from these main rivers we shall
find lesser ones branching off on both sides, and running
right and lefb through the country, and from these again
still smaller streams and brooks; furthermore, we shall find
the ground falling in every direction towards these natural
watercourses, forming a ridge, more or less elevated, run-
ning between them, and separating from each other the
districts drained by each separate stream.
In all cases it should be the first business of a person,
engaged in laying down a line of road, to make himself
thoroughly acquainted with all these features of the
country; he should possess himself of a plan or map,
showing accurately the course of all the rivers and princi-
pal watercourses, and upon this he should further mark the
lines of greatest elevation, or the ridges separating the
several valleys through which they flow; it would also be
of peculiar service if the plan contained contour lines
showing the comparative levels of any two points, and the
rates of declivity of every portion of the country’s surface.
The system of showing upon plans the levels of the
ground by means of contov/r lines is one of so much utility,
not only in the selection of roads and all other lines of
communication, but in the drainage of towns, as well as
their supply with water, in the drainage and irrigation of
lands, and for almost all purposes, that we have inserted a
plan of the City of London* (fig. 2), which illustrates its
application. It will be observed that, upon this plan, there
are a number of fine lines traversing its surface in various
directions, and, where they approach the borders of the
map, having figures written against them: these lines are
termed contour lines, and they denote that the level of the
ground is identical throughout the whole of their course, that
* This plan is taken from the Report on the Health of Towns, and is
made from levels taken from Mr. Butler Williams.I52
THE EXPLORATION OF ROADS.
is, that every part of the ground over which the line passes
is a certain height above some known fixed point, which
height is indicated by the figures written against the line.
If we examine the map, for example, we shall find at the
point a, in Smithfield Market, a line with the figures 57
attached, which indicates that the ground in that spot is 57
feet above some point to which all the levels are referred.
If we now trace the course of the line, we shall find that it
cuts Newgate Street at the point b, passes thence to the
bottom of Paternoster Bow at the point i, through St.
Paul’s Churchyard at c, to Cheapside at d ; it then curves
round towards the point from which it first started, and
crosses Aldersgate Street twice, at E and f ; it then, after
intersecting Pore Street, Cripplegate, in the point a, again
meets the boundary of the City at h. We learn, there-
fore, by tracing the course of this line, that each of these
points is the same height, namely, 57 feet above a certain
fixed point, termed the datum; and which point, in the
present instance, is 10 feet below the top of the cap-stone
at the foot of the step, on the east side of Blackfriars
Bridge. Each of the lines in fig. 2 indicates a difference of
level of 18 inches; so that by counting the number of these
lines which intersect a street or road in any given distance,
we ascertain at once the rise or fall in the same. Thus, if we
look at the line of Bishopsgate Street, we see near the
north end the contour line 45, indicating that that point in
the street is 45 feet above the datum, and we find nine
lines intersecting the street between this point and the
top of Comhill; we know, therefore, that this point is
(1*5 x9=) 13*5 feet above the other end of the street, or
58*5 feet above the datum. We are also enabled to judge
of the rate of inclination of the ground by the proximity
or distance of these lines; thus we see that on the north-
ern side of the City, where the ground is comparatively
level, the lines are far apart; whereas, on the side next the
Thames, and again on each side of the line of Parringdon
Street (which marks the course of the valley of the old
river Pleet), where the surface is very hilly, we find the
contour lines close together.THE EXPLOBATION OP BO ADS.
53
We have prepared a plan (fig. 3) showing an imaginary
tract of country, to illustrate more clearly the mode of show-
ing by means of contour lines the physical features which
may belong to it. The hatched line, e r a h i, is supposed to
be the elevated ridge, encircling the valley shown in the
plan; the fine black lines are contour lines, indicating that
the ground over which they pass is at the altitude above
some known mark expressed by the figures written against
them in the margin; and it will be observed that these
lines, by their greater or less distance, produce the effect
of shading, and make apparent to the eye, at one view,
the undulations and irregularities in the surface of the
country.
In laying out a line of road there are three cases which
may occur, and each of these is exemplified in the plan
(fig. 3) : first, the two places to be connected may be both
situated in the same valley, and upon the same side of it,
that is, not separated from each other by the main stream
which drains the valley, as the towns a and b on the plan;
and this is the simplest case which can occur : secondly,
although both in the same valley, they may be on the oppo-
site side of the valley, as a and o, being separated by the
main river: thirdly, they may be situated in different
valleys, so as to be separated by an intervening ridge of
ground more or less elevated, as a and d. In laying out an
extensive line of road, it frequently happens that each of
these cases occurs, and that, perhaps, frequently, during its
course; we shall, therefore, now proceed to point out the
various methods which might in each case be pursued, and
afterwards to lay down the general principles which should
determine our choice of them.
Before doing so, however, we should perhaps observe,
although it must be almost obvious to all, that the most
perfect condition of a road is that in which its course is
perfectly straight, and its surface perfectly level; and that,
all other things being the same, that is the best road which
approaches nearest to this state.
Now, in the first case supposed (that of two towns situ-54
THE EXPLORATION OF EOADS.
Fig. 3.
9	12 15	15	15	18 21	24 27	30THE EXPLORATION OP ROADS.
65
ated on the same side of the main valley), there are two
methods which might be pursued in forming a communica-
tion between them: we might either make a road following
the direct line between them, shown by the thick dotted line
a B, or we might adopt a line which should gradually and
equally incline from one town to the other, supposing them
to be at a different level, or, if at the same, keeping at that
level throughout its entire course, and following all the
sinuosities and curves which the irregular formation of the
country might render necessary for the fulfilment of these
conditions. And in the first method (that of a direct line
between the two places), we might either form a level or
equally-inclined road from one to the other, forming em-
bankments and cuttings where necessary to attain these
objects, or we might avoid these expensive works, and make
the surface of the road conform to that of the country.
Now, of all these the best is the straight and equally-
inclined (or level, as the case may be) road, although at
the same time it is the most expensive ; and if the import-
ance of the traffic passing between the places is not suf-
ficient to warrant so great an outlay, it will then become a
matter of consideration whether the course of the road
should be kept straight, its surface being made to undulate
with the natural face of the country, or whether, a level or
equally-inclined line being taken for its surface, the course
of the road should be made to deviate from the direct line,
and follow the winding course which such a condition is
supposed to necessitate.
In the second case, that of two places situated on oppo-
site sides of the same valley, we have, in like manner, the
choice of a perfectly straight line to connect them, which
would probably require a heavy embankment if the road
were kept level, or steep inclines if it followed the surface
of the country; or we may, by winding the road, carry it
across the valley at a higher point, where, if the level road
were taken, the embankment would not be so high, or, if
kept on the surface, the inclination would be reduced.
In the third case, we have in like manner the alternative50
THE EXPLOBATIOX OF BOADS.
of carrying the road across the intervening ridge in a per-
fectly straight line, or of deviating to the right or left, and
crossing at a point where the ridge is less elevated.
In all these cases, the proper determination of the
question, which of these courses is the best under certain
circumstances, involves one of the most difficult points to
solve, which is, the comparative advantages and disadvan-
tages of inclines and curves; that is, what additional in-
crease in the length of a road would be equivalent to a
given inclined plane upon it, or conversely, what inclination
might be given to a road, as an equivalent to a given
decrease in its length. In order to a correct solution of
these questions, it is requisite that we should know the
comparative force required to draw different vehicles with
given loads upon level and variously-inclined roads. We
shall, therefore, before proceeding further, investigate this
subject, and show the manner in which we may determine
the tractive force required upon roads of any given inclina-
tion.
It has been attempted to investigate mathematically the
resistances which oppose themselves to the motion of
various descriptions of vehicles drawn along horizontal
roads, whose surfaces were formed of different materials,
and in different states of smoothness. No satisfactory
result, however, has been obtained, because we are ignorant
of the data which are essentially requisite to enable us to
arrive at a correct conclusion. We should, for instance,
know the relative amounts of resistance occasioned by a
wheel drawn along a hard smooth road, such as a good
macadamized road, so hard that the wheel can make no
appreciable impression upon it; upon the same road when
newly covered with stones, and when the passing of the
wheel over them crushes these stones in a greater or less
degree; upon a gravel road, the surface of which is soft, so
that the wheel in its passage sinks into the road and forms
a rut; upon a similar road covered with stones which are
partially crushed and partially forced down into the soft
road by iiie wheel passing over them; or upon a stone pave-THE EXPLORATION OE ROADS.
57
ment, such as is common in the streets of towns, laid with
more or less regularity, and in passing over which the
resistance is felt in jerks, as the wheels hound from stone
to stone. Many other cases might be mentioned, in which
we should be equally at a loss to assign a correct value to
the resistance which would be experienced by a carriage
drawn along the particular description of road supposed.
Although, therefore, some of the attempts which have
thus been made have been very ingenious, and have shown
the mathematical skill of the investigator, they have done
little besides, and would be out of place in the present
work. In cases of this description, the best practical
method of proceeding is by experiments sufficiently careful
and extensive to determine the amount of resistance in each
particular case, from which we may then determine an
empyrical formula or rule, which will enable us to generalise
the results of our experiments, and apply them with suf-
ficient accuracy for practical purposes to any particular, case
we may wish.
The following are the general results of the experiments
made by M. Morin upon this subject, at the expense of the
French Government:—
1st. The traction is directly proportional to the load, and
inversely proportional to the diameter of the wheel.
2nd. Upon a paved or hard macadamized road the resist-
ance is independent of the width of the tire, when it
exceeds from three to four inches.
3rd. At a walking pace the traction is the same, under
the same circumstances, for carriages with springs and
without them.
4th. Upon hard macadamized, and upon paved roads, the
traction increases with the velocity : the increments of
traction being directly proportional to the increments of
velocity above the velocity 3*28 feet per second, or about
2± miles per hour. The equal increment of traction thus
due to each equal increment of velocity is less as the road
is more smooth, and the carriage less rigid or better hung.
5th. Upon soft roads of earth, or sand or turf, or roads
c 358
THE EXPLORATION OF ROADS.
fresh and thickly gravelled, the traction is independent of
the velocity.
6th. Upon a well-made and compact pavement of hewn
stones, the traction at a walking pace is not more than
three-fourths of that upon the best macadamized roads
under similar circumstances; at a trotting pace it is equal
to it.
7th. The destruction of the road is in all cases greater,
as the diameters of the wheels are less, and it is greater in
carriages without than with springs.
The next experiments which we shall quote, are those of
Sir John Macneill,* made with an instrument invented by
him for the purpose of measuring the tractive force re-
quired on different descriptions of road, under various
circumstances. The general results which he obtained are
given in the following table, the numbers in which exhibit
the tractive force requisite to move a weight of a ton under
ordinary circumstance, at a very low velocity upon the
several kinds of road mentioned.
Description of road.	Force, in pounds, re- quired to move a ton.
On a well-made pavement .			33 46 65 147
On a road made with six inches of broken stone of great\ hardness, laid either on a foundation of large stones, set in L the form of a pavement, or upon a bottoming of concrete.. J On an old flint road, or a road made with a thick coating of) broken stone, laid on earth 	J On a road made with a thick coating of gravel, laid on earth..	
Sir John Macneill has also given the following arbitrary
formulae,t for calculating the resistance to traction on
various kinds of roads; they have been deduced from a
considerable number of experiments made on the different
kinds of road specified below, with carriages moving at
various velocities. Putting r for the force required to
* Sir H. Parnell on Roads, p. 73.	+ Ibid., p. 464.THE EXPLORATION OE ROADS.
59
move the carriage, w the weight of the carriage, w that of
the load, all expressed in pounds, v the velocity in feet per
second, and c a constant number, which depends upon the
surface over which the carriage is drawn, and the value
of which for several different kinds of road is as follows ;—
On a timber surface ........................................ c =»	2
On a paved road............................................. „	2
On a well-made broken stone road, in a dry clean state ...... ,,	5
On a well-made broken stone road, covered with dust........... „	8
On a well-made broken stone road, wet and muddy............... „	10
On a gravel or flint road, in a dry clean state ............. ,,	13
On a gravel or flint road, in a wet and muddy state........... „	32
We have, in the case of a common stage wagon-
B =W + W. + Z+OVi .
93	40
and in the case of a stage coach—
B=W-+w + — + e v;
100	40
(1-)
(2.)
These formulae, being reduced to verbal rules for the
convenience of those not conversant with algebraical ex-
pressions, are as follows :—
Bule.—Divide the weight of the carriage when loaded,
in pounds, by 93 if a wagon, or 100 if a coach, and to the
quotient add one-fortieth of the weight of the load only;
the sum, added to the velocity in feet per second, multiplied
by the proper number taken from the above table for the
particular kind of road, will give the force in pounds
required to draw the carriage at the given velocity upon
that description of road.
Bor example: what force would be requisite to move a
stage-coach weighing 2,060 lbs., and having a load of 1,100
lbs., at a velocity of 9 feet per second, along a broken stone
road covered with dust ?
Here we have60
THE EXPLOBATIOH OF BO ADS.
2060 + 1100
100
+
ii2? +8x9 = 181-1 lbs.
40
for the force required.
We next pass on to consider the additional resistance
which is occasioned when the road, instead of being level,
is inclined in a greater or less degree. In order to simplify
the question, let us suppose the whole weight to be sup-
ported on one pair of wheels, and that the tractive force is
applied in a direction parallel to the surface of the road.
On this supposition let a b (fig. 4) represent a portion of
an inclined road, c being a carriage just sustained in its
Fig. 4.
B D
position by a force acting in the direction c d ; now it is
evident that the carriage is kept in its position by three
forces, namely, by its own weight (equal w) acting in the
vertical direction c r, by the force (equal r) applied in the
direction c d parallel to the surface of the road, and by the
pressure (equal p) which the carriage exerts against the
surface of the road acting in the direction c e, perpendicu-
lar to the same. To determine the relative magnitude of
these three forces, draw the horizontal line ag, and the
vertical one B g ; then, since the two lines c r and b g are
parallel, and are both cut by the line a b, they must make
the two angles geb and abg equal; also the two angles
o e f and a G b are equal, being both right angles ; there-
fore the remaining angles fce and bag are equal, and the
two triangles cee and abg are similar. And as the three
sides of the former are proportional to the three forces by
which the carriage is sustained, so also are the three sidesTHE EXPLORATION OF ROADS.
61
of the latter, namely, a b, or the length of the road is pro*
portional to w, or the weight of the carriage, b g, or the
vertical rise in the same to f, or the force required to sus-
tain the carriage on the incline, and a g on the horizontal
distance in which this rise occurs to p, or the force with
which the carriage presses upon the surface of the road.
We have, therefore,
and
w
w
AB
AB
F
p
GB,
AG.
And if we make a g such a length that the vertical rise of
the road is exactly one foot, we shall have
F =
W
A B
W
Va G2 + l“
w . sin £
(3.)
,	W. AG
and p = ----:
AB
W. AG
—-------— W . COS
s/ AG2 +1
&
(4.)
in which 0 is the angle bag.
These formulae reduced to verbal rules are as follows:—
To find the force requisite to sustain a carriage upon an
inclined road (the effects of friction being neglected), divide
the weight of the carriage, including its load, by the inclined
length of the road, the vertical rise of which is one foot,
and the quotient is the force required.
To find the pressure of a carriage against the surface of
an inclined road, multiply the weight of the loaded carriage
by the horizontal length of the road, and divide the product
by the inclined length of the same; the quotient is the
pressure required.
Example.—What is the force required to sustain a car-
riage weighing 3,270 lbs. upon a road, the inclination of
which is one in thirty, and what is the pressure of the
same upon the surface of the road ?
Here the horizontal length of the road (a g) being 30,
the inclined length (ab=v/ ag2 + 1) is 30*017, and we
have, by the first rule, 3,270 -5- 30*017 = 108*93 lbs. for
the force required to sustain the carriage on the road; and,62
THE EXPLORATION OF ROADS.
by the second rule, (3,270 X 30) -a- 30 017 = 3,269*9 lbs.
for the pressure of the carriage upon the surface of the
road.
Since the pressure of a carriage on a sloping road is found
by multiplying its weight by the horizontal length of the
road and dividing by the inclined length, and as the former
is always less than the latter, it follows that the force with
which a carriage bears upon an inclined road is less than
its actual weight, as will be seen in the foregoing example,
in which it is about two pounds less; unless, however, the
inclination is very steep, it is not necessary to calculate the
pressure, which may be assumed to be equal to the weight
of the carriage.
If r expresses the resistance which has to be overcome
in moving any particular carriage at a given rate upon a
horizontal road, then r x f will be the resistance upon
ascending a hill, and R — F upon descending a hill, with
the same velocity, in both cases neglecting the decrease in
the weight of the carriage produced by the inclination of
the road. Taking, however, this decrease into considera-
tion, the following modification in the formulae (1.) and
(2.) will be requisite to adapt them to an inclined road:—
sin -f cv. (5.)
and in that of a
(w + w w\
~Qq~ +4q I. cos & + (w + «)).Bm0 + cv . (6.),
the upper sign being taken when the vehicle is drawn down
the incline, and the lower when it is drawn up the same.
Neglecting the decrease in the weight of the carriage, in
order to ascertain the resistance in passing up or down a
hill, we have only to calculate by the rule already given at
page 64 the resistance on a level road, to which, if the
carriage ascends the hill, we must add, or if it descends,
subtract, the force requisite to sustain the carriage on the
(w -f w w\
*~93 ^"40/ -cos/S + Cw + w).
in the case of a common stage wagon,
stage coach,THE EXPLOBATIOH OF EOADS.
63
inclined road, calculated by the rule at page 66; the sum
or difference, as the case may be, will express the resistance
required.
As an example, let us take, as before, the case of a stage-
coach weighing 2,060 lbs., besides a load of 1,100 lbs., and
having to be moved at a velocity of 9 feet per second, along
a broken stone road whose surface is covered with dust, and
inclined at the rate of one in thirty.
Then the force to sustain the coach on this slope will be
3160
= 105*3 lbs.
which, added to the force already found at page 60 as being
requisite to move the same coach on a level road, will be
(105*3 + 131*1 = ) 236*4 lbs. for the force required to
move the coach with a velocity of 9 feet per second up an
inclination of one in thirty ; and subtracted from the same,
will be (131*1—105*3 =) 25*8 lbs., the force required to
move the coach with the same velocity down the same
inclination.
The same example worked by formula (6) will give
/2060 + 1100\
V 100	)
• 9995 + (2060 + 1100) *0333 + 8 x9
= 236*3 lbs.
when the carriage is drawn up the incline, and
/2060 + 1100\ (

100
V
■ 9995 — (2060 + 1100) *0333 + 8 x9
= 25*84 lbs.
when the carriage is drawn down the incline, the result
being the same as that given by the rule.
The following table has been calculated in order to show
with sufficient exactness for most practical purposes the
force required to draw carriages over inclined roads, and
the comparative advantage of such roads and those which
are perfectly level. The first column expresses the rate
of inclination, and the second the equivalent angle; the64
THE EXPLORATION OP ROADS.
two next columns contain the force requisite to draw a
common stage-wagon weighing with its load 6 tons, at a
velocity of 4*4 feet per second (or 3 miles per hour) along
a macadamized road in its usual state, both when the hill
ascends and when it descends; the fifth and sixth columns
contain the length of level road which would be equivalent
to a mile in length of the inclined road, that is, the length
which would require the same mechanical force to be ex-
pended in drawing the wagon over it as would be neces-
sary to draw it over a mile of the inclined road; the four
next columns contain the same information as the four last
described, only with reference to a stage coach supposed to
weigh with its load 3 tons, and to travel at the rate of 8*8
feet per second, or 6 miles per hour.THE EXPLORATION OF ROADS.
65
		Anolb with the Horizon.	For a Stags Wagon.				For a Staob Coach.			
	Rats or Inclination*		Force required to draw the wagon up the in- cline.	Force required to draw i the wagon down the i incline.	Equivalent length of level road for an as- cending; wagon.	Equivalent length of level road for a de- scending wagon.	Force required to draw the coach up the in- cline.	Force required to draw the coach down the incline.	Equivalent length of level road for an as- cending coach.	Equivalent length of level road for a de- scending coach.
l in 600		o t // 0 5 44	lbs. 286	lbs. 241	Miles. 1*085	Miles. *9150	lbs. 373	lbs. 350	Miles. 1030	Miles. *9690
”	575	0 5 59	287	240	1*088	*9116	373	350	1032	•9676
	550	0 6 15	288	239	1*093	*9074	374	349	1033	•9662
	525 0 - 6 33		289	238	1*097	*9029	374	349	1*035	*9646
	500 0 6 53		291	237	1*102	*8979	375	348	1-037	•9629
	475 0 7 14		292	235	1*107	*8926	376	347	1-039	•9605
	450	0 7 38	294	234	1*113	*8869	377	347	1041	•9588
	425	0 8 5	295	232	1*120	*8801	377	346	1043	•9563
	400	0 8 36	297	230	1*128	*8725	378	345	1-046	•9535
	375	0 9 10	300	228	1*136	•8642	380	344	1*049	•9505
	350	0 9 49	302	225	1*146	*8543	381	342	1053	•9469
?j	325	0 10 35	305	222	1*157	*8433	382	341	1056	•9430
w	300	0 11 28	309	219	1*170	*8301	384	339	1061	*9381
j>	290 0 11 51		310	217	1*176	*8245	385	338	1064	*9358
	280 0 12 17		312	216	1*182	*8179	386	338	1066	.9336
>9	270 0 12 44		314	214	1*189	*8111	386	337	1068	•9314
99	260 0 13 13		315	212	1*196	*8039	387	336	1*071	•9286
99	250 0 13 45		317	210	1*204	*7963	388	335	1*074	•9259
99	240 0 14 19		320	208	1*212	*7876	390	334	1*077	•9226
99	230	0 14 57	322	205	1*222	*7785	391	332	1*080	•9192
99	220	0 15 37	325	203	1*232	*7683	392	331	1084	•9156
99	210	0 16 22	328	200	1*243	*7573	394	330	1088	•9115
99	200	0 17 11	331	197	1*255	*7451	395	328	1*092	*9071
99	190	0 18 6	334	193	1*268	*7319	397	326	1097	•9024
99	180	0 19 6	338	189	1*283	*7171	399	324	1*103	•8968
99	170	0 20 13	343	185	1*300	•7004	401	322	1*109	•8908
99	160	0 21 29	348	180	1*319	•6814	404	320	1*116	•8839
99	150	0 22 55	353	174	1*341	•6587	406	317	1*123	•8761
99	140	0 24 33	360	168	1*364	•6359	410	314	1*132	•8673
99	130	0 26 27	367	160	1*392	*6079	413	310	1*142	•8573
99	120	0 28 39	376	152	1*425	*5752	418	306	1154	•8451
99	110 0 31 15		386	142	1*451	*5491	423	300	1*169	•8308
99	100	0 34 23	398	129	1*510	*4903	429	294	1*185	•8142
99	95	0 86 11	405	122	1*537	*4634	432	291	1*195	•8045
99	90	0 38 12	413	114	1*566	*4338	43 6	287	1*206	*7937
99	85	0 40 27	422	106	1*600	*4004	441	282	1-219	*7801
99	80	0 42 58	432	96	1*637	•3629	446	278	1*232	*767766
THE EXPLOBATION OF ROADS
Rats os Inclination.		Angle with thb Horizon.			For a Stags Wagon.				For a Stags Coach.			
					Force required to draw the wagon up the in- cline.	Force required to draw the wagon down the incline.	Equivalent length of level road for an as- cending wagon.	Equivalent length of level road for a de- scending wagon.	Force required to draw the coach up the in- cline.	Force jrequired to draw the coach down the incline.	Equivalent length of level road for an «w- cending coach.	Equivalent length of level road for a de- scending coach.
		o	/	//	lbs.	lbs.	Miles.	Miles.	lbs.	lbs.	Miles.	Miles.
1 in	75	0	45	51	443	85	1*680	•3204	451	272	1-247	•7522
11	70	0	49	7	456	72	1-728	•2719	457	266	1-265	•7345
11	65	0	52	54	470	57	1-784	•2161	465	258	1-285	•7143
11	60	0	57	18	488	40	1-850	1505	474	250	1-309	•6903
„	55	1	2	30	508	19	1-926	0736	484	239	1-337	•6620
11	50	1	8	6	533	—	2019	—	496	227	1-371	•6283
11	45	1	16	24	562	—	2133	—	511	212	1-412	•5871
11	40	l	25	57	600	—	2274	—	530	194	1-464	•5354
n	35	1	38	14	648	—	2-456	—	554	170	1-530	•4690
15	34	1	41	8	659	—	2-499	—	559	164	1-546	•4535
55	33	1	44	12	671	—	2-544	—	565	158	1-562	4370
15	32	l	47	27	684	—	2-593	—	572	152	1-580	•4193
15	31	1	50	55	697	—	2-644	—	578	145	1-599	•4007
55	30	1	54	37	712	—	2-699	—	586	138	1*619	-3805
55	29	1	58	34	727	—	2-758	—	593	130	1-640	•3592
•<5	28	2	2	5	744	—	2-820	—	602	122	1-663	•3363
15	27	2	7	2	762	—	2-888	—	610	113	1-688	•3119
H	26	2	12	2	781	—	2-960			620	103	1-714	•2854
15	25	2	17	26	801	—	3-038	—	630	93	1-743	•2566
55	24	2	23	10	823	—	3-120	—	641	82	1-774	•2257
55	23	2	29	22	847	—	3-213	—	653	69	1-808	•1919
15	22	2	36	10	874	—	3-313	—	666	56	1-844	•1554
15	21	2	43	35	903	—	3-423	—	681	42	1.884	•1150
11	20	2	51	21	933	—	3-538	—	696	26	1-926	•0730
15	19	3	0	46	970	—	3-677	—	714	8	1*977	•0221
55	18	3	10	47	1009	—	3-826	—	734	—	2032		
55	17	3	21	59	1053	—	3-991	—	756	—	2092		
55	16	3	34	35	1102	—	4178	—	780	—	2160		
55	15	3	48	51	1157	—	4-388	—	807	—	2-234	,—'
15	14	4	5	14	1221	—	4-629	—	839	—	2-322	—
55	13	4	23	56	1294	—	4-906	—	875	—	2-423		
51	12	4	45	49	1379	—	5-229	—	918	—	2-540		
15	11	5	11	40	1480	—	5-611	—	968	—	2-679	—
15	10	5	42	58	1600	—	6067			1028	—	2-846		
15	9	6	20	25	1747	—	6-623	—	1101			3048		
55	8	7	7	30	1929			7-315	—	1192	—	3-300		
15	7	8	7	48	2162	—	8199	•—'	1308	—	3-621	—THE EXPLOBATIOff OE HOADS.
67
The foregoing table may be considered as affording a
view of the comparative disadvantage of hilly roads with
light and heavy traffic; the stage wagon, weighing 6 tons
and travelling at the speed of 3 miles per hour, may be
taken as a fair average for goods traffic, and the stage
coach, weighing 3 tons and running 6 miles an hour, for
passenger traffic. Prom the table we perceive that hills
act much more unfavourably on the former than on the
latter. The force which would be requisite to move the
wagon on a level road would be 264 lbs., and that to move
the coach 362 lbs., being an excess of 98 lbs. for the trac-
tion of the coach; but with a road inclined at the rate of
1 in 600, this excess is only (373 — 286 =) 87 lbs., and
when the inclination of the road amounts to about 1 in 70
the forces required to draw them become equal; as the
inclination of the road increases beyond this, the excess of
the force requisite to draw the wagon over that necessary
to move the coach increases rapidly (as will be seen in the
table), until, at an inclination of 1 in 7, it amounts to
(2162 - 1308 =) 854 lbs.
If we compare the forces required to draw either the
wagon or coach up and down any given incline, we shall
find that the former is as much greater than the force re-
quired on a level road as the latter is less than the same;
it might thence be concluded that in the case of a vehicle
passing alternately along the road, no real loss would be
occasioned by the inclination of the road, since as much
power would be gained in the descent of the hill as was
lost in its ascent. Such is not, however, practically the
fact, for while the inclinations of the road render it neces-
sary in the ascending journey to have either a greater num-
ber or more powerful horses than would be requisite if the
road were entirely level, no corresponding reduction can be
made in the descending journey; we must still have horses
sufficient to draw the vehicle along the level portions of the
road; nor will (generally speaking) the horses have less to
do in descending the hill, since they have frequently to68
THE EXPLOBATION OF BO AD 3.
push back, to prevent the speed of the coach becoming
accelerated beyond the bounds of safety.
In a practical point of view, therefore, we may consider
that the fifth and ninth columns in the foregoing table ex-
press the length of level road which would be equivalent
to a mile of road with the stated inclination, the former
giving the result for heavy traffic, and the latter for pas-
senger traffic. For instance, opposite 1 in 75, we find in the
ninth column 1*247 miles, or nearly a mile and a quarter,
stated as the length of a road having that inclination which
would be equivalent to one mile of a similar road perfectly
level, because the same force would be requisite to move a
coach of 3 tons at a velocity of 6 miles per hour along one
as along the other. Although, however, they might be
considered equal as far as the power requisite for traction
was concerned, in other respects one might be more advan-
tageous than the other; as for instance, the shorter road
would cost least for repairing, and would occupy least time
in being passed over. The table, therefore, merely expresses
the equivalent length as far as the mechanical power re-
quired for the traction is concerned; the relative merits in
other respects depending generally upon so many various
circumstances as to render it quite impossible to lay down
any specific rules for their determination.
We shall now return to the subject of the selection of
route, and proceed to explain the course which should be
pursued to obtain the requisite data, to enable a correct
determination to be arrived at.
In laying out a new line of road, the first proceeding is
usually, after a general examination of the country, to lay
down upon the best map which can be procured one or
more lines, for the purpose of being more carefully exa-
mined. If possessed of a contour map of the district, such
as we have described, this proceeding will be greatly faci-
litated; we shall, however, suppose that such is not the
case, since there are very few instances in which a road-
maker would be likely to find such a plan for his use. HisTHE EXPLORATION OE ROADS.
G9
next proceeding should be, to make an accurate survey
of the lands through which the several lines that he has
sketched out pass, which should he afterwards plotted, or
laid down to such a scale as will allow the smallest features
to be shown with sufficient accuracy and distinctness: a
scale of ten chains to the inch for the open country, with
enlarged plans of towns and villages upon a scale of three
chains to the inch, will generally be found sufficient.
Careful levels should also be taken along the course of each
line; and at certain distances (depending upon the nature
of the country) lines of levels should be taken at right
angles with the original line. In taking these levels the
heights of all existing roads, rivers, streams, or canals,
should be noted, and bench marks should be left at least
every half-mile, that is, marks made on any fixed object,
such as a gate-post, or the side of a house or bam, &c., the
exact height of which is ascertained* and registered in the
level-book, so that, in case of a deviation being made in
any portion of the lines, the levels of that part may be
taken without the necessity of again going over the other
parts of the line. A section should be formed from these
levels, having the same horizontal scale as the general plan,
and such a vertical scale as will show with distinctness the
inequalities of the ground: if the horizontal scale is ten chains
to the inch, the vertical scale may be 20 feet to the inch.
Pig. 5 is supposed to be such a plan as we have described,
plotted on a scale of ten chains to the inch, and showing a
district through which it is wished to form a road; we have
shown one line running nearly straight across the plan, and
a deviation therefrom, which, although longer, would run on
more favourable ground. Pigs. 6 and 7 are sections show-
ing the levels of the surface of the ground, the former on
the straight line, and the latter on the deviation from it.
We have shown in these sections and on the plan the in-
formation which will be requisite in enabling the engineer
to lay down the course of the road, and to arrange the
position and dimensions of the various culverts, bridges,
and other works belonging to the same.Scale of Chains.
Fig. 5.
iJunction witb\
Existing Road.)
RSver.
Sueam.
B iver.
St cam.
K
Junotion
Existing Road./
THE EXPLORATION OP ROADS.	71
3/ia. 6.
I	97*25
Horizontal Scale.	Vertical ScaleFig. 7.
41 26
auirj- mu^if (£THE EXPLORATION OP HOADS.
73
By reference to these drawings, it will be seen (fig. 5)
that the straight line has to cross a stream at b, and the
river twice at c and d ; and also that it must pass from b
to e, over a swamp or morass of such a nature that, if a
solid embankment is formed, it is probable that a very
large quantity of ground will be absorbed, beyond what
the section would indicate; added to which, from the river
being liable to be flooded, it will be necessary to form
bridges with several capacious openings at those points
where the intended road crosses the river. These disad-
vantages attending the more obvious route would induce
the engineer to sketch out some other line, by which they
would be avoided. And he would then have the levels
taken, and the requisite information, to enable him to
choose between the two.
The manner in which the sections should be drawn, and
the informatioii to be given upon them, are shown in figs.
6 and 7. In addition to which the following data should
be obtained, and entered either in the survey field-book, or
in the level-book.
At the point B (fig. 5) the line crosses a stream 8 feet in width and
1 foot deep; in flood this stream brings down a considerable quantity of
water.
At the point 0 on the section the river is much narrower and not so
deep as at other places, in consequence of a great portion of its waters
finding a passage through the marshy ground on either side. Its width
is 16 feet, and its depth 2 feet; the velocity of its current is 95 feet per
minute; the height of its surface at the present time is 30*10 feet abov*
the datum; and the angle of skew which the course of the stream makes
with the line of the road is 62 degrees.
At the point n the river is 27 feet wide, and 2£ feet in depth; its
velocity 87 feet per minute; the height of its surface above the datum
29*96 feet; and the angle of skew 49 degrees.
The ground from b to b is of a very soft boggy nature, and full of
water.
The height to which the river has risen during the highest flood
known, at the bridge at f on the plan, is 35 feet above the datum; the
water-way at that time was 90 feet, and the sectional area of the open-
ings through which the water then flowed was 550 square feet. The
same flood at the lower bridge, at 6 on the plan, was 35*3 feet above'
D74	THE EXPLORATION OF ROADS.
the datum; the water-way was 102 feet, and the sectional area nearly
600 square feet.
The deviation line only crosses one stream at M on the plan and sec-
tion. The present width of this stream is 15 feet, and its depth 18
inches; hut in times of flood it rises to the same height as the river, and
brings down a large body of water. The present height of its surface
above the datum is 31*25 feet, and the angle which its course makes
with the line of road 85 degrees.
We have introduced the foregoing in order to show the
kind of data which should be obtained by those engaged in
taking the levels and survey for road-making.*
A cross section should also be taken of each of the exist-
ing roads near their junction with the intended road; the
use of which is to show to what extent, if any, the levels
of the existing roads might be altered, the better to suit
that of the new road.
Possessed of the sections, figs. 6 and 7, we next proceed
to lay down the line of the road, or, in other words, to de-
termine the levels at which it shall be formed. As it is
desirable that the road should always be dry, it should be
at least a foot above the level of the flood; and if kept at
37*25 feet above the datum, which is the height of the
existing road at i, we shall effect this object. Upon draw-
ing a line at this level upon the section, we perceive that
an embankment will have to be formed from the road at i,
across the valley to the point where this line meets the
ground at k, and that the remainder of the road from k
to h will be in a cutting. Now the obvious principle, in
arranging the levels of a road, would be so to adjust the
cuttings and embankments that the ground taken from one
should form the other. In the present instance, however,
this is impossible, because the level of the road is deter-
mined by other circumstances, and necessitates the forma-
tion of a very long embankment with but very little cutting,
* The information relative to the rivers crossed, such as is given above,
should always be obtained, in order that the bridges constructed over them
may be adequate for the passage of the water brought down in time of
floods.THE EXPLOBATION OB BOADS.
75
therefore rendering it necessary for ground to be obtained
from some other source, with which to form the embank-
ment. In order to produce as much cutting as possible,
the line should be kept at the same level as before until it
becomes necessary to rise to attain the level of the existing
road at H; if an inclination of 1 in 50 be given to this last
part of the road, the distance at which the rise will com-
mence will be 200 feet from h, the difference of level being
4 feet. We have therefore to add to the other disadvan-
tages already mentioned, as belonging to the straight line
of road, that of requiring the formation of a large embank-
ment, and the necessity of making an excavation in some
other place, to afford the earth for that purpose.
We will now examine the section of the deviation line,
and see what improvement can be thereby effected. We
must, as before, keep the level of the lowest portion of the
road 37*25 feet above the datum; and if we draw a line at
that level on the section, fig. 7, we shall find that the quan-
tity of embankment is very much reduced, and that there
will now be no difficulty in adjusting the cutting between
H and L, so as exactly to afford the amount of filling re-
quired. A few trials will show that if the line be kept at
the same level until within sixteen chains of h, and then
carried up at a regular inclination, this object will be
effected, and that the amount of cutting and embankment
will be very nearly equal. This latter will therefore be
the line which the engineer would select as the best; and
having done so he would proceed to mark the course of the
road on the ground, by driving a stake into the ground on
its centre line at every chain (or 66 feet) ; he would then
take very careful levels of the height of the ground at every
one of these points, and at any intermediate point, where
any undulation or change of level occurred, and wherever
the level of the ground varied to any extent in a direction
at right angles with the course of the road, he would take
levels from which to make transverse or cross sections of
the ground.
Prom these levels a working section should be made,
n 21--2	3	45	67	8	9 IT. 1
Datura 45 Feet below top of Milestone at A on Plan.THE EXPLORATION OF ROADS.
77
having a horizontal scale of not less than five chains to the
inch, and a vertical scale of 20 feet to the inch; a portion
of the section plotted to these scales is shown in fig. 8;
the level of the surface of the ground above the datum, at
every chain at the points where stakes have been driven
into the ground, should be figured-in on the section, as
shown in the column a, and the depth of cutting or height
of embankment, at the same points, should be given in
another column, b. This last column is obtained by taking
the difference between the level of the surface of the ground
and the level of the road. It will be observed that upon
the section there are two parallel lines drawn as represent-
ing the line of road; the upper line is intended to repre-
sent the upper surface of the road when finished, while the
lower thick line represents what is termed the formation
surface, or the level to which the surface of the ground is
to be formed, to receive the foundation of the road; in the
section we have made the formation 15 inches below the
finished surface of the road, which will therefore be the
thickness of the road itself. All the dimensions on the
section are understood to refer to the formation level; and
the height of the latter above the datum should be figured-
in wherever a change in its rate of inclination takes place,
which should be marked by a stronger vertical line being
there drawn, as shown at c.
When the cuttings are of any depth, trial pits should be
sunk at about every ten chains to the depth of the intended
cutting, in order to ascertain the nature of the ground, and
to determine the slopes at which the sides of the cutting
would safely stand; and also at what slopes the same earth
would stand when formed into the embankments. The cut-
tings and embankments should then be numbered on the
section, and the slopes intended to be given to each stated
upon the same. The contents of the cutting or embank-
ment, that is, the number of cubic yards which will have
to be moved for its formation, with the intended slope,
should then be calculated and stated upon the section. The
manner of calculating these quantities will be explained78
THE EXPLORATION OP ROADS.
in a subsequent chapter, on estimating the cost of the
road.
Wherever rivers or streams are crossed, bridges or cul-
verts must be introduced, and of these detail drawings
should be prepared, and reference made to them on the
working section;
A working plan should also be constructed on the same
horizontal scale as the section, upon which the position of
the center stakes should be shown; and on this plan the
road should be drawn in of its correct width on its upper
surface, and another line showing the foot of the slopes.
The stakes on the plan should be numbered consecutively,
to facilitate reference to any part of the line, and the width
of land required at every stake should be calculated in the
manner which we are about to describe, and entered in a
kind of table, from which the width of land required for
the purpose of the road may be ascertained at every chain.
We will suppose that, in the present case, the finished
width of the road itself is to be 40 feet, and that an addi-
tional 6 feet will be required on each side for the ditch and
bank; we have then 26 feet as the side width of the road
without ally slopes, or where the road is on the same level
as the ground, and wre shall observe that in the following
table, wherever there is no cutting or embankments (as at
stakes Nos. 1 and 30), this is the width given in the fourth
column. To find the heights at the other stakes we must
add to the constant width (viz. 26 feet) the height of em-
bankment or depth of cutting (as the case may be) multi-
plied by the ratio of the slope. Thus, in the first cutting,
the ratio of the slopes being (as stated on the section)
1 to 1, we have simply to add the depths of the cutting at
each stake to 26 feet, and we obtain the numbers given in
the fourth column. After the 21st stake we leave the cut-
ting, and the ratio of the slopes then becomes 1-J- to 1; we
have then to add one and a half times the height of the
embankment, and we then in like manner obtain the num-
bers in the fourth column.THE EXPLORATION" OP ROADS.
79
No. of stake on the plan.	Depth of cutting.	Height of em- bankment.	Distance of side fence from cen- ter line.	No. of stake on the plan.	| 1 0 1 Q	Height of em- bankment.	Distance of side fence from cen- ter line.
	Feet.	Feet.	Feet.		Feet.	Feet.	Feet.
1	0*00	—	260	17	2*33	—	283
2	0*58	—	26*6	18	2*52	—	28-5
3	093	—	26-9	19	2*20	—	28-2
4	1*20	—	27*2	20	1*60	—	276
5	1*56	—	27*6	21	075	—	26*8
6	1*91	___	27*9	22	_	0*55	268*
7	2*04	—	28-0	23	—	2*20	29*3
8	1*87	—	27*9	24	—	352	31*3
9	1*90	—	27*9	25	—	400	320
10	2*07	—	28*1	26	—	379	31*7
11	2*17	—	28*2	27	—	2*60	299
12	2-35	—	28-4	28	—	1-25	27*9
13	2*30	—	28*3	29	—	030	26*5.
14	2*25	—	283	30			000	260
15	250	—	28*5	31	—	0-33	26*5
16	205	—	28*1				
After ascertaining the side widths as above, the next
operation is to set out the same on the ground, driving in
another stake at every chain at the correct distance on each
side of the center one. A grip about 4 or 5 inches wide
should then be cut from stake to stake, so as to mark both
the center and sides of the road upon the ground by a
continuous line. The side lines thus set out, it must be
remembered, are not the foot of the slopes, but include
6 feet on each side for a bank and ditch; another stake
should therefore be driven at every chain 6 feet within the
outer stakes on each side, and another grip cut to mark the
foot of the slopes.
A strong post should next be fixed into the ground upon
the center line wherever a change in the inclination of the
road takes place (as at the 17th stake in the present in-
stance), upon which a cross piece should be placed at the
intended height of the formation surface of the road, and
* The slopes here change from 1 to 1, to 1J to 1.80
ON THE SECTION OE ROADS.
intermediate heights should be put up at such distances as
will enable the workmen to keep the embankments to their
proper level. In cuttings, pits must be sunk in a similar
manner, at certain intervals, to the depth of the formation
surface, to serve as guides to the excavators in forming the
cutting.
CHAPTER II.
ON THE SECTION OE ROADS.
Having in the preceding chapter explained at length the
objections which belong to inclined roads, and given rules
for determining, with as much accuracy as the nature of
the question will admit, the amount of resistance which
they oppose to the haulage of vehicles, it will not be neces-
sary in this place to say much on the longitudinal inclina-
tion, or gradient, as it is technically termed, of roads.
"Where hills or gradients are necessary, they should be
made as easy as possible; and, although with 'all hills a
certain amount of additional power must be required to
draw a carriage up them, so long as the inclination is within
certain limits, the hilly road may be considered as safe as a
level one would be. This limit depends upon the nature
and condition of the surface of the road, and is attained in
any particular case when the inclination of the road is made
equal to the limiting angle of resistance for the materials
composing its surface, that is, when it is such that a car-
riage once set in motion on the road would continue its
descent without any additional force being applied. As
soon as this limit is past, the carriage would descend with
an accelerated velocity, unless the horses or other moving
force were employed to restrain it; and, although in such a
case the use of a drag, by increasing the resistance, would
in a measure obviate the danger, yet the injury done to theON THE SECTION OE ROADS.
81
surface of the road by the use of the drag renders it desira-
ble to dispense with it altogether. The following table,
taken from the second volume of the Rudiments of Civil
Engineering, shows the rate of inclination at which this
limit is attained on the various kinds of roads mentioned in
the first column. The values of the resistances on which
this table is calculated are those given by Sir John Mac-
neill, and already quoted at page 58.
Description of the road.	Force in lbs. required to move a ton.	Limiting angle of re- sistance.	Greatest inclination which should be given to the road.
Well-laid pavement 		33	o / 0 50	1 in 68
Broken stone surface on a bottom of rough't			1 in 49
	46	1 11	
pavement or concrete 		j			
Broken stone surface laid on an old flint road	65	1 40	lin 34
Gravel road 		147	3 45	1 in 15
The following table of gradients will be found of con-
siderable value in laying out and arranging roads ; the first
column contains the gradient, expressed in the ratio of the
height to the length; the two next, the vertical rise in a
mile and a chain respectively; the fourth column, the angle
(fi page 61) of inclination with the horizontal; and the last
column, the sine of the same angle, which is inserted for
facilitating the calculation of the resistances occasioned by
the gradient.82
ON THE SECTION OF EOADS,
I Gradient.		Vertical rise in a mile.	Vertical rise in a chain.	Angle (0) -which gra- dient makes with the horizontal.			Sine of angle 0.	Gradient.		Vertical rise in a mile.	Vertical rise in a chain.	Angle (0) which gra- dient makes with the horizontal.			Sine of angle 0.
1 in 10		528*0	6-60	o 5	42	// 58	09960	1 in 60		88*0	1-10	o 0	57	18	01667
	11	480*0	6-00	5	11	40	•09054	99	65	81*2	1-02	0	52	54	•01539
	12	440*0	5*50	4	45	59	•08309		70	75-4	*94	0	49	7	•01429
	13	406*1	5*08	4	23	56	•07670	99	75	70-4	•88	0	45	51	01334
	14	377*1	4-71	4	5	14	•07128	99	80	66-0	*82	0	42	58	•01250
	15	352*0	4*40	3	48	51	•06652		85	62-1	*78	0	40	27	•01177
	16	330-0	4-12	3	34	35	•06238	99	90	58*7	*73	0	38	12	•01111
	17	310-6	3-88	3	21	59	•05872	99	95	55-6	•69	0	36	11	*01053
	18	293-3	3-67	3	10	47	•05547	95	100	52*8	•66	0	34	23	•01000
	19	277-9	3*47	3	0	46	•05256	91	no	48*0	*60	0	31	15	•00909
	20	264-0	3-30	2	51	21	•04982	95	120	44-0	*55	0	28	39	•00833
	21	251-4	3-14	2	43	35	•04757	99	130	40 *6	*51	0	26	27	•00769
	22	240 0	3*00	2	36	10	04541	99	140	37-7	•47	0	24	33	•00714
99	23	229*6	2-87	2	29	22	•04344	99	150	35*2	•44	0	22	55	•00666
99	24	220-0	2-75	2	23	10	•04163	99	160	33-0	*41	0	21	29	•00625
99	25	211-2	2-64	2	17	26	•03997	99	170	31*1	*39	0	20	13	•00588
99	26	203*1	2*54	2	12	2	•03840	99	180	29-3	•37	0	19	6	00556
99	27	195-5	2-42	2	7	2	•03694	99	190	27*8	*35	0	18	6	•00527
99	28	188-5	2-36	2	2	5	•03551	99	200	26-4	*33	0	17	11	00500
99	29	182*1	2*28	1	58	34	•03448	59	210	25-1	*31	0	16	22	•00476
99	30	176*0	2-20	1	54	37	•03333	9*	220	24-0	*30	0	15	37	00454
99	31	170-3	2*13	l	50	55	•03226	99	230	230	•29	0	14	57	•00435
99	32	165-0	2-06	l	47	27	•03125	99	240	22-0	•27	0	14	19	•00417
99	33	160-0	200	1	44	12	•03031	99	250	21-1	•26	0	13	45	•00400
99	34	155-3	1*94	1	41	8	•02941	99	260	20-3	•25	0	13	13	•00385
99	35	150-9	1-88	1	38	14	•02857	99	270	19-6	•24	0	12	44	•00370
99	36	146-7	1-86	1	35	28	•02777	99	280	18-9	*24	0	12	17	•00357
99	37	142-7	1*78	1	32	53	•02702	99	290	18-2	•23	0	11	51	•00345
99	38	138 9	1-74	1	30	27	•02631		300	17-6	•22	0	11	28	•00334
99	39	135-4	1-69	1	28	8	•02563	99	325	16*2	*20	0	10	35	•00308
99	40	1320	1-65	1	25	57	•02500	<9*	350	15-1	•19	0	9	49	•00286
99	41	128-8	1-61	1	23	50	•02438	99	375	140	*18	0	9	10	•00267
99	42	125*7	1-57	1	21	50	•02380	99	400	13-2	*17	0	8	36	•00250
99	43	122-8	1-53	1	19	56	•02325	99	425	12*4	•16	0	8	5	•00235
99	44	120-0	1-50	1	18	7	•02272	99	450	11-7	•15	0	7	38	•00222
99	45	117-3	1-47	1	16	24	•02222		475	11-1	•14	0	7	14	•00210
99	46	114-8	1*44	1	14	43	•02173	99	500	10-6	*13	0	6	53	•00200
*9	47	112*3	1-40	1	13	8	•02127	99	525	10-1	*12	0	6	33	•00191
99	48	110 0	1 37	1	11	37	•02083	99	550	9-6	•12	0	6	15	•00182
99	49	107*7	1-35	1	10	9	•02040		575	9-2	•11	0	5	59	•00174
99	50	105-6	1*32	1	8	6	•01981	99	600	8-8	*11	0	5	44	•00167
99	55	96-0	1-20	l	2	30	*01818								ON THE SECTION OE HOADS.
83
"We next come to the subject of the width and transverse
form which should be given to roads. As regards the first,
the width to be given to the road, we should certainly
recommend a wide road; it is an error to suppose that the
cost of repairing a road depends entirely upon the extent
of its surface, and consequently increases just as we increase
its width; the cost per mile of road depends more upon
the extent and nature of the traffic, and unless extremes be
taken, it may be asserted that the same quantity of material
would be necessary for the repair of a road, whether wide
or narrow, which was subjected to the same amount of
traffic; with the narrow road, the traffic, being confined
more to one track, would wear the road more severely than
when spread over a larger surface ; the expense of spread-
ing the material over the wider road would be somewhat
greater, but the cost of the materials might be taken as the
same. One of the advantages of a wide road is, that the
wind and sun exercise more influence in keeping its surface
dry. The first cost of a wide road is certainly greater than
that of a narrow one, and that nearly in the ratio of its
increased width.
For roads situated between towns of any importance,
and exposed to much traffic, the width should certainly not
be less than 30 feet, besides a footpath of 6 feet; and in
the immediate vicinity of large towns and cities, the width
should be still further increased. No specific rules can,
however, be given for the width in such situations; ex-
perience will soon show what width is requisite in any
given situation.
The form to be given to the cross section of a road is a
subject of much importance, and one upon which much
difference of opinion exists. Some advocate a considerable
curvature in the upper surface of the road, with the view
of facilitating the drainage of its surface; while others
(and that the majority) are averse to a road being much
curved, for reasons which we will presently state. Again,
it is the practice of some to form the road on a flat surface
transversely; while others propose giving a dip to the84
OK THE SECTIOK OE ROADS.
formation surface each way from the center, on the sup-
position that the drainage of the road will be thereby
facilitated.
Now it must be obvious to all, that the only advantage
resulting from curving the transverse section of the road is,
allowing the water, which would otherwise collect upon its
surface, to drain freely off into the side ditches. It has
been urged by some that, in laying on fresh material upon
a road, it is necessary to keep the center much higher than
the sides; because, in consequence of the majority of
carriages using the center of the road, that portion will
wear quicker than the sides, and, unless made originally
much higher, when so worn it will necessarily form a hollow
or depression, from which the water cannot drain. Now it
is entirely overlooked by those who advance this argument,
that the only reason why carriages use the center in pre-
ference to the sides of a road, is because of its rounding
form, it being only in that situation that the carriage stands
upright; if the road were comparatively flat, every portion
would be equally used; but on very convex roads, the
center is the only portion of the road on which it is safe to
travel. On this subject Mr. M‘Adam remarks, in giving
evidence before a committee of the House of Commons,*
“ I consider a road should be as flat as possible with regard
to allowing the water to run off it at all, because a carriage
ought to stand upright in travelling as much as possible.
I have generally made roads three inches higher in the
center than I have at the sides, when they are eighteen
feet wide; if the road be smooth and well made, the water
will run off very easily in such a slope.’* And, in answer
to the question, “ Do you consider a road so made will not
be likely to wear hollow in the middle, so as to allow the
water to stand, after it has been used for some time ?” he
replies,—“No; when a road is made flat, people will not
follow the middle of it as they do when it is made extremely
convex. Gentlemen will have observed that in roads very
convex, travellers generally follow the track in the middle,
* Parliamentary Report on the Highways of the Kingdom, 1819, p. 22.OK, THE SECTION OF ROADS.
85
which is the only place where a carriage can run upright,
by which means three furrows are made by the horses and
the wheels, and water continually stands there ; and I think
that more water actually stands upon a very convex road
thm on one which is reasonably flat” And on the same
subject, Mr. Walker remarks,* “ A road much rounded is
dangerous, particularly if the cross section approaches to-
wards the segment of a circle, the slope in that case not
being uniform, but increasing rapidly from the nature of
the curve, as we depart from the middle or vertical line.
The over-rounding of roads is also injurious to them, by
either confining the heavy carriages to one track in the
crown of the road, or, if they go upon the sides, by the
greater wear they produce, from their constant tendency to
move down the inclined plane, owing to the angle which
the surface of the road and the line of gravity of the load
form with each other; and, as this tendency is perpendi-
cular to the line of draught, the labour of the horse and
the wear of the carriage wheels are both much increased
by it.”
The drainage. of the surface of the road is then the only
useful purpose which will be answered by making it con-
vex ; and even this in but a very imperfect manner, in
consequence of the irregularities and roughness which we
find even in the best roads. The surface of a road is much
more efficiently drained by a small inclination in the direc-
tion of its length, than by a much greater transverse slope;
on this subject Mr. Walker has very justly remarked,+
“ Clearing the road of water is best secured by selecting a
course for the road which is not horizontally level, so that
the surface of the road may, in its longitudinal section,
form, in some degree, an inclined plane; and when this
cannot be obtained, owing to the extreme flatness of the
country, an artificial inclination may generally be made.
When a road is so formed, every wheel-track that is made,
being in the line of inclination, becomes a channel for
* Parliamentary Report, 1819, p. 49,
t lb. p. 48.86
OK THE SECTIOK OE ROADS.
Eig.
9. carrying off the water much more effectually than
can he done by a curvature in the cross section or
rise in the middle of the road, without the danger
or other disadvantages which necessarily attend
the rounding a road much in the middle. I con-
sider a fall of about an inch and a half in ten feet
to be a minimum in this case, if it is attainable
without a great deal of extra expense.” While,
then, the advantages attending the extreme con-
vexity of roads is so small, the disadvantages are
considerable; on roads so constructed, vehicles
must either keep upon the crown of the road, and.
so occasion an excessive and unequal wear of its
surface, or use the sides, with the liability of being
overturned. The evidence of coach-masters and
others, taken before the Committee of the House
of Commons, and appended to the report from
which we have already quoted, quite bears out the
view here taken, and shows that many accidents,
and much danger, have arisen from the practice of
forming roads with an excessive amount of con-
vexity.
In making the above remarks, we must be under-
stood as only disapproving of the practice (which
has been but too prevalent) of forming roads with
cross sections rounding in an extreme degree, and
not as advocating a perfectly, or nearly, flat road,
as many, who have fallen into the opposite error,
have done. We should recommend, as the best
form which could be given to a road, that it cross
section should be formed of two straight lines in-
clined at the rate of about 1 in 30, and united at
the center or crown of the road by a segment of a
circle, having a radius of about 90 feet. This form
of section is shown in fig. 9, and the rate of incli-
nation there given is quite sufficient to keep the
surface of a road drained, provided it is in good
order and free from ruts; if such is not the case,OK THE SECTION OF ROADS.
87
no amount of convexity which could be given to the road
would be of any avail, as the water would still remain in
the hollows or furrows.
The form of cross section here suggested is equally
adapted to all widths of road, as the straight lines have
merely to be extended at the same rate of inclination, until
they meet the sides of the road.
The foregoing remarks apply only to the exterior or
upper surface of the finished road; with regard to the form
which should be given to the bed upon which the road is
to be formed, a similar difference of opinion exists as to
whether it should be flat or rounding. In this case we are
of opinion that, except where the surface upon which the
road has to be formed is a strong clay or other soil imper-
vious to water, no benefit will result, as far as drainage is
concerned, in making the formation surface or bed of the
road convex. It should be borne in mind that, after the
road materials are laid upon the formation surface, and have
been for some time subjected to the pressure of heavy
vehicles passing over them, they become, to a certain ex-
tent, intermixed; the road materials are forced down into
the soil, and the soil works up amongst the stones, and the
original line of separation becomes entirely lost. If the
surface upon which the road materials were laid were to
remain a distinct flat surface, perfectly even and regular,
and into which the road materials could not be forced, then
it would be of use to give such an inclination to it as would
allow any water which might find its way through the
crust or covering of the road to run off to the sides of the
same; although, even then, it would have to force a pas-
sage between the road materials and the surface on which
they rest; such is, however, as we have already remarked,
far from being the case; and, therefore, we hold that, unless
under peculiar circumstances, no water which had found
its way through the hard compact service of the road itself
would be arrested by the comparatively soft surface of its
bed, and carried off into the side ditches, whatever the
slope which might be given to it. While, however, we88
ON THE SECTION OF BO ADS.
believe that, as far as drainage is concerned, it is useless to
form the bed or formation surface of the road with a trans-
verse slope, we should, nevertheless, give it the same, or
nearly the same, form as that which we have just recom-
mended for its upper finished surface; with the object of
making the two surfaces parallel, and so giving an equal
depth of road material over every portion of the road. In
this respect we do not agree with some road-makers, who not
only recommend a less depth of road materials to be put on
the sides than on the center of the road, but further advise
that an inferior description of material should there be
employed. On this subject we cannot do better than quote
the following remarks, which Mr. Hughes has made on
this point, and which are very much to the purpose :*—
“ A very common opinion is, that the depth of material in
the center of the road should be greater than at the sides,
but, for my part, I have never been able to discover why
the sides of the road should be at all inferior to the middle
in hardness and solidity. On 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 practice is, obviously, to make the sides equally hard
and solid with the center. In many roads, even where
considerable traffic exists, the ‘ only good part of the road
consists of about eight or ten feet in the center, 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 center 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 center. Another mischievous consequence
is, that when it becomes necessary to repair the center 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
* The Practice of Making and Repairing Roads, by Thomas Hughes.
1838, p. 12.ON THE SECTION OF BO ADS.
89
coaches. On the other hand, if equal labour and materials
be expended on the whole breadth of the road, it is evident
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 road: and this
alone will of course render it necessary to curve the bed
of the road.”
Too much attention cannot be paid to the drainage of
roads, both as regards their upper surface, and that of the
substratum on which they rest. To assist the surface
drainage, the road should be formed with the transverse
section which we have shown in fig. 9, and on each side of
the road a ditch should be formed of sufficient capacity to
receive all water which can fall upon the road, and of such
a depth, and with a sufficient declivity, to conduct the same
freely away. When footpaths have to be constructed on
the sides of the roads, a channel or watercourse should be
formed between them, and small drains, formed of tiles or
earthem tubes (such as are used for underdraining lands),
should be laid under the footpath, at such a level as to take
off all the water which may collect in this channel, and
convey it into the ditch. In the best-constructed roads,
these side channels should be paved with flints or pebbles ;
the drains under the footpath should be introduced about
every 60 feet, and should have the same inclination (viz. 1
in 30) as we recommended for the sides of the road, as
shown in fig. 9: a greater inclination would be objection-
able. It is a very frequent mistake to give too great a fall
to small drains, the only effect of which is, to produce such
a current through them as to wash away or undermine
the ground around them, and ultimately cause their own
destruction. When a drain is once closed by any obstruc-
tion, no amount of fall which could be given to it would
again clear the passage; while a drain, with a considerable
current through it, would be much more likely to be
stopped from foreign matter being carried into it, which a
less rapid stream could not have transported there.90
ON THE SECTION OP ROADS.
In the case of a road whose surface was drained in the
way which we have just described, and whose surface was
composed of proper materials in a compact state, very little
water would find its way through to the substratum; with
some descriptions of soil, however, it would be desirable to
adopt means for maintaining the foundation of a road in a
dry state; as, for instance, when the surface was a strong
clay through which no water could percolate, or when the
ground beneath the road was naturally of a soft, wet, or
peaty nature. Under such circumstances it would be de-
sirable to provide for its proper drainage, by a species of
underdrainage. As soon as the surface of the ground had
been formed to the level intended for the reception of the
road materials, trenches should be formed across the road,
from a foot to eighteen inches in depth, and about a foot
wide at the bottom, the sides being sloped as shown in
fig. 10. The distances at which these drains ought to be
formed would depend in a great measure on the nature of
the soil; in the case of a strong clay soil, or one naturally
very wet, there should be one about every 20 feet, and this
Fig. 10.
Formation Surface.
Fig. 11.
ROAD-WAV
lOK THE SECTION OF BOADS.
91
distance might be increased as the ground
became firmer or drier. In these trenches,
a drain not less than 4 inches square inter-
nally should then be formed either of old
bricks, drain-tiles, flat stones, or in any other
mode used for underdrains, and the re-
mainder of the trench should be filled with
coarse stones free from all clay or dirt, in
the manner shown in fig. 10. Of course
these drains must have a fall given them
from the center of the road into the ditches
on either side; an inclination of 1 in 30 will
be sufficient. When the road is level in the
direction of its length, these drains should
run straight across, but on those portions
of the road which were inclined, the drains
should be formed, as shown on the plan, fig.
11, somewhat in the form of a very flat v,
the point being in the center of the road,
and the drains making an acute angle with
the line of the road, in the direction in which,
it falls; the amount of this angle should not
be greater than is shown in fig. 11.
WTien a road with footpaths is under-
drained in the manner which we have just
described, it will not be necessary to form
drains from the side channel under the foot-
path into the > ditch, as shown in fig. 9, but
merely to carry up a little shaft, constructed
in the same way as the drain, from the drain
to the channel, covering the same with a
small grating to prevent leaves or other sub-
stances, which might choke the drain, being
carried into it. This method of forming the
drains is shown at a in fig. 12.
Fig. 12.
Materials92
ON THE CONSTRUCTION OF ROADS.
CHAPTER III.
ON THE CONSTRUCTION OF ROADS.
"We next proceed to the mode which should be pursued in
the construction of the road itself, but before doing so, we
must say a few words on the foundation upon which the
road materials are to be placed. On this subjct, again,
a great difference of opinion exists. By a few, amongst
whom we may mention Mr. M‘Adam, it has been main-
tained that a yielding and soft foundation for a road is
better than one which is firm and unyielding; and he has
gone so far as to say that he “ should rather prefer a soft
one to a hard one,” and even a bog, “If it was not such
a bog as would not allow a man to walk over it.”* The
principles upon which this opinion was founded were, that
the road on the soft foundation being more yielding or
elastic, the materials of which the covering of the road was
formed would be less likely to be crushed and worn away
by the passage of a heavy traffic over them than when
placed on a hard solid. The contrary opinion is, however,
that which has received the largest number of advocates,
and is that which we ourselves hold; and we feel assured
that there is no more general cause of bad roads than their
being formed upon a soft foundation. We would most
strongly urge the necessity of securing a firm, solid, and
dry substratum for the road materials to rest upon; and
we are quite satisfied that, however good the materials
themselves may be, and however much care may be be-
stowed upon the manner in which they are put on, unless
a good foundation has been previously prepared, the whole
of the materials and labour will be only thrown away. The
outer surface of the road should be regarded merely as a
covering to protect the actual working road beneath, which
latter should be sufficiently firm and substantial to support
* Parliamentary Report, 1819, p. 23.ON THE CONSTBUCTION OF ROADS.
93
the whole of the traffic to which it may be exposed. The
real use of the road materials laid over it should be only to
protect this actual road from being worn and injured by
the horses’ feet and the wheels, or from the action of the
weather. And this lower, or sub^road, as it may be called,
being once properly constructed, would last for ever, merely
the outer case or covering requiring to be renewed from
time to time, so as always to preserve a sufficient depth for
the protection of the sub-road.
We may very conveniently class roads, according to the
manner in which their foundation is formed, as follows:—
1st. Roads having no artificial foundation, but in which
the covering materials are laid on the ground.
2nd. Roads having a foundation of concrete.
3rd. Roads having a paved foundation.
And each of these might be again divided according to the
kind of material employed as a covering.
The first of these classes will certainly contain by far the
largest proportion of the roads in this country. But it
should only be employed in cases where the importance of
the road is not sufficient to warrant any large expenditure,
and when the amount of traffic to be anticipated is small;
for we are certainly of opinion that is a very mistaken eco-
nomy which would incur a large permanent annual outlay
for repairs, to save in the original cost of constructing the
road, and we are satisfied that, in this sense, a road with
a paved or concrete foundation will always be found less
expensive than one formed without such a foundation.
Where, however, circumstances may render it necessary
to construct a road upon the natural surface of the ground,
every care should be taken to make it as solid as possible.
If the ground is at all of a soft or wet nature, deep ditches
should be cut on each side of the line of the road, and cross
underdrains should be formed in the manner already de-
scribed at page 91. And where the ground is very soft, a
layer of faggots or brushwood, from 4 to 6 inches in depth,
should be laid over the surface of the ground before laying
on the road materials. In cases of embankments, or where94
ON THE CONSTRUCTION OP ROADS.
the ground under the road has been recently deposited, the
surface should be either rolled or pmned, that is, beaten
with heavy beetles, so as to ensure as great a degree of
solidity as possible. The same mode of proceeding should
be followed, even where it is intended to form either a
paved or concrete foundation, for, as we before remarked,
too much care cannot be bestowed on that part of the
road.
The employment of concrete composed of gravel and
lime was first proposed by Mr. Thomas Hughes, and the
following remarks upon its use are quoted from his work
on roads.#
“ The use of lime concrete, although an introduction of
modem times, and certainly one of rather a novel charac-
ter, derives its real origin from a very remote period, We
have indisputable evidence that the Romans, in construct-
ing 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 consequence 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 proportion of gravel to lime is
that of four to one. 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 slacked and saturated. The
bed of concrete having been spread to the depth of 6 inches
over the half breadth of the road, the surface is then
covered over with 6 inches of good hard gravel or broken
The Practice of Making and Repairing Roads, p. 44.OK THE COKSTBTTCTIOK OE BOAES.
95
stone, and tliis depth is laid on in two courses, of 3 inches
at a time, the first course being frequently laid on a few
hours after the concrete has been placed on 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 become 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 be-
come hard before laying on the first covering. The bene-
ficial 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 par-
tially into the concrete, and thus remain fixed in a matrix,
from which they could not easily be dislodged. The lower
pebbles being thus fixed, and their rolling motion conse-
quently prevented, an immediate tendency to bind is com-
municated 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.
“ The experiment of using concrete on the Brixton-road,
although not at present on a very extensive scale, has been
tried under circumstances very far from being favourable,
and on a part of the road .which had hitherto baffled every96
ON THE CONSTBTJCTION OE HOADS.
attempt to make it solid. Since the concrete 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 exten-
sive way, to several trusts under whom he acts.”
Mr. Penfold, himself, states the result of an experiment
made by him upon the Walworth-road. " It was raised by
nine inches of concrete, and six of granite and Kentish
rag-stone mixed; and in some parts it was covered by rag
and flints. The improvement is so great, with respect to
the draught, and so desirable with respect to the saving in
the annual repair, that the trust have directed it to be ap-
plied to upwards of two miles of road upon which the
greatest traffic exists.” *
One of the principal advantages attending the employ-
ment of concrete as a foundation for roads is, that in this
manner a good and solid road may be made with materials,
such as round pebbly gravel, which, in any other mode of
application, would be but very ill suited to the purpose, and
would form a very imperfect road. And this description of
gravel is that which is by far the most frequently met with.
The gravel selected for this purpose should be free from
any kind of dirt, clay, or other impurity, and should consist
of stones and sand, mixed in about such proportions that
the latter would just fill the interstices of the former.
The gravel should then be mixed with the proper quantity
of ground unslacked lime—in ordinary cases five or six
parts of gravel and one of lime will be found to answer;
after which, sufficient water being added to effect the slack-
ing of the lime, the whole should be quickly, but thoroughly,
mixed up, and then immediately thrown into place, and
trimmed off at once to the proper form intended to be
given to its upper surface; the first layer of broken stones'
or screened gravel, as the case may be, should then, as Mr.
* A Practical Treatise on the best Mode of Making and Repairing Roads,
by Charles Penfold, p. 31.Off THE COffSTBTJCTIOff OP BOADS.	97
Hughes directs, be put over just at that period when the
concrete is about to set, and which time a very few trials
will suffice to determine.
The other mode of forming an artificial foundation to
which we have alluded, was introduced by Mr. Telford, and
consists in forming a rough pavement on the top of the for-
mation-surface, which is afterwards covered by the road
materials. The following is an extract from one of Mr.
Telford’s specifications for a portion of the Holyhead-
road:—“ Upon the level bed prepared for the road mate-
rials, a bottom course or layer of stones, is to be set by
hand, in form of a close firm pavement; the stones set in
the middle of the road are to be 7 inches in depth: at 9
feet from the center, 5 inches; at 12 from the center, 4
inches; and at 15 feet, 3 inches. They are to be set on
their broadest edges lengthwise across the road, and the
breadth of the upper edge is not to exceed 4 inches, in any
case. All the irregularities of the upper part of the said
pavement are to be broken off by the hammer, and all the
interstices to be filled with stone chips, firmly wedged or
packed by hand, with a light hammer; so that whep the
whole pavement is finished, there shall be a convexity of
4 inches in the breadth of 15 feet from the center.” *
The stone which Telford employed for this purpose, was
generally such as would have been totally unfit for most
other purposes, both on account of its inferior quality, and
from the smallness of its dimensions. In comparing the
relative merits of these two methods of forming the founda-
tions of roads, due regard must be had to the nature of the
materials found in the locality in which the road has to be
formed. Where stone is plentiful, and easily procured, the
paved foundation would be the best; while, in a neigh-
bourhood where stone was scarce, but gravel and lime
abundant, the preference must be given to the concrete
foundation.
The foundation of the road having been prepared, in
Sir H. Parnell on Hoads, p. 1S3.98
ON THE CONSTRUCTION OF ROADS.
either of the inodes which we have described, the next pro-
ceeding is, to form a firm and compact covering to protect
the foundation from being injured, and to form a smooth
surface for carriages to travel upon. Wow, in order to fulfil
this double office efficiently, the materials of, which this
covering is composed should possess the property of becom-
ing quickly united into one solid mass, whose surface should
be smooth and hard, and at the same time not liable to be
broken to pieces, or ground into dust, by the wheels or the
horses’ feet. All the materials which have been applied
for this purpose belong to one of two kinds; either angular
fragments of broken stone of different sorts, or gravelly
pebbles, more or less round: and it is essential to the
formation of a good road that the distinction here pointed
out be kept always clearly in view, because a totally differ-
ent mode of proceeding must be adopted to form a perfect
road with these two classes of material. The want of
attention to the distinction which we here point out has led
to much discussion and misapprehension upon the subject
of employing clay, chalk, or other material, as a binding
upon roads.
If the materials of which the road covering is to be
formed are in angular masses, then no binding of any
description is requisite; as it is found that they quickly
become united by dovetailing, as it were, amongst each
other, and that in a much firmer manner than they would
become by the use of any kind of artificial cement.
When, however, the stones, instead of being angular,
are round and pebbly, like gravel stones, it then becomes
necessary to mix with them just sufficient foreign matter,
of a binding nature, as will serve to fill up the interstices
between the stones, which otherwise would roll about, and
prevent the road from becoming solid.
We have, then, two methods of cementing or solidifying
the surface of a road: one, by the mechanical form of the
materials themselves forming a species of bond; the other,
by the use of some cementing or binding matter. And in
comparing the relative merits of the two, the preferenceON THE CONSTRUCTION OE ROADS.
99
must certainly be given to the former, that in which the
stones are caused to unite from their dovetail form, without
the use of any cementing material. The principal reason
for giving this preference is, that roads formed with stones
so united, are not affected materially by wet or frosty
weather; whereas, those whose surfaces are composed of
pebbly stones united by some cementing material become
loose and rotten under such circumstances, from the
cementing material becoming softened by the wet, and
reduced to a loose pulverulent state by subsequent frost.
The first method, that of forming the road-covering entirely
with angular pieces of stone, without any other material, was
first strongly recommended by Mr. M‘Adam, and all sub-
sequent experience has shown its superiority over every
other which has been employed. The most important
quality in stone for road-making is toughness ; mere hard,
ness without toughness is of no use, as such stone becomes
rapidly reduced to powder by the action of the wheels.
Those stones which have been found to answer this purpose
best are, the whinstones, basalts, granites, and beach
pebbles. The softer descriptions of stone, such as the sand-
stones, are not fitted for this purpose, being far too weak
to resist the crushing action of the wheels. The harder
and more compact limestones may be employed; but,
generally speaking, the limestones are to be avoided, in
consequence of their great affinity for water, which causes
them, in frosty weather, which has been preceded by wet,
to split up into a pulverulent state, and destroys the solidity
of the road.
Next in importance to the quality of the stone is its
proper preparation; this consists in reducing it to angular
fragments of such a size that they will pass freely through
a ring of 2£ inches in diameter in every direction; that is,
that their largest dimensions shall not exceed that mea-
sure.
The stone, having been thus prepared, should then be
evenly spread over the surface prepared for the foundation
of the road, to the depth of about 6 inches; and the road
r 2100
OH THE CONSTBTJCTION OE HOADS.
should then be opened for traffic. In Mr. Telford’s
specifications, he usually directed that on the top of this
coating of broken stone a layer of good clean gravel, about
an inch and a half in depth, should be spread before throw-
ing the road open for use. The reason for this practice
was, to lessen the extreme unevenness of the surface, and
to render the road more pleasant to pass over when first
opened; it would be better, however, for the public to put
up with the temporary inconvenience of a rough road,
because the gravel does a permanent injury to the road,
and lessens in a considerable degree the property which
the stones possess of uniting into a compact solid mass*
Broken stone, being so superior to gravel for the pur-
pose of road-making, should always be employed where it
can be easily obtained. There are, however, many situations
in which gravel is the only available material. The quality
of gravel varies so considerably, that while some kinds may,
when properly prepared, form a very excellent road, others
may be entirely worthless; of this last are those kinds of
gravel the stones composing which are of the sandstones
and flints, for even these last, although hard, are so exces-
sively brittle as to be immediately crushed by the passing
of the wheels over them. The gravel when taken from the
pit should be passed over a screen which will allow all
stones less than three quarters of an inch to pass through
it, and the fine stuff, or hoggin, as it is technically termed,
thus obtained, should be reserved for forming the footpaths;
the remainder, which has not passed through the screen,
should have all the stones whose greatest dimension is more
than inches removed and broken, and it would be de-
sirable that these broken stones should be reserved for the
upper layer. In screening the gravel, especially as it first
comes out of the pit, a certain portion of loam will gene-
rally be found to adhere to the stones, and this should by
no means be separated from them, for, as we have already
mentioned, although angular broken stones require no ex-
traneous substance to cause them to bind, the case is diffe-
rent with the pebbles, of which most gravel is composed,ON THE CONSTRUCTION OF ROADS.
101
which require a certain amount of loam, clay, or chalk, to
fill up the interstices between the stones, and prevent them
from being rolled about, as they otherwise would be. On
this subject, Mr. Hughes has made some observations so
much to the purpose that we cannot do better than quote
them: *—“ In laying on this upper covering many surveyors
commit a great error in not making a distinct difference be-
tween 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 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 conse-
quently 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 pro-
portion 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? * * * A long
course of experience, accompanied by attentive observa-
tions on these details in the practice of road-making, has
convinced 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 substance. When
the gravel is placed on a road without being sufficiently
* The Practice of Making and Repairing Roads, p. 15.102
ON THE CONSTRUCTION OF ROADS.
cleaned, the constant wear and tear, aided by the occur-
rence of wet weather, causes the harder material or actual
gravel to be pressed close together; and the surplus of soft
binding material remaining 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
pulverised 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 sufficiently cleaned. Kegardless 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
it becomes entirely divested of all that may properly be
considered the binding part of the material.’*
The gravely when thus prepared by screening, should be
laid on and spread to a uniform depth of not more than
6 inches over the whole road, which may then be thrown
open to the use of the public: particular care and atten-
tion, however, is required to be given to new roads when
first opened for traffic; a sufficient number of men should
be employed to keep every rut raked in the moment it
appears, and guards or fenders should be placed on the
road, to oblige the vehicles to pass over every part of its
surface in turn. If these precautions are not taken, years
may elapse before the road attains a firm condition; and
many roads have been permanently ruined through the
want of proper attention when first used. When ruts areOK THE CONSTRUCTION OF EOAfcS.	103
once formed, every succeeding vehicle using the road keeps
in the same track, deepening and increasing the rut, which
in wet weather becomes filled with water, which, having
no other means of escape, slowly penetrates the sides and
bottom of the rut, rendering them so soft as to be still
further acted upon by each succeeding carriage. These
ruts once formed, a much larger outlay is required to re-
pair the injury than would have prevented its occurrence,
besides the inconvenience, danger, and expense to the pub-
lic, in being obliged to travel on a road when in such a
condition.
Amongst the substances which we mentioned might be
mixed with clean gravel to enable it to bind was chalk.
Now we think it necessary to say a few words on the use
of chalk on roads, as much misapprehension exists on the
subject, and many roads have been ruined from its improper
use. There are two modes in which chalk may be advan-
tageously employed in the construction of roads. It may
be laid in the very bottom of the road, to form the founda*
tion; but it must be at such a depth as to be entirely beyond
the influence of frost, otherwise it will quickly destroy the
road, for chalk has a very powerful affinity for water, or
rather, to speak more correctly, capillary attraction for it,
in consequence of which it readily absorbs all the moisture
which finds its way through the road covering; and herein
consists its value if judiciously applied, for the water thus
absorbed would otherwise have penetrated to the founda-
tion of the road and rendered it soft. If, however, the
chalk be placed within the influence of frost, the water,
which is only mechanically held by the chalk, will, in the
act of congealing, expand, and by so doing rend the chalk
into a thousand fragments, and reduce it in fact to a pulve-
rulent state, which the succeeding thaw changes into a soft
paste or mud. The other purpose for which chalk may be
employed is, as we have already mentioned, to be mixed
with gravel in order to make it bind; in using chalk, how-
ever, for this purpose, it should be borne in mind that it is
only required when the gravel is perfectly clean and free104
ON BEPAIBING AND IMPBOVING BOADS.
from other binding matter; the mixing it with gravel al-
ready containing sufficient clay or loam is not only useless,
but is positively injurious; and, even when the gravel is of
such a nature as to require being mixed with chalk, great
care should be taken not to add too much, for it is not
with chalk as with the loam or clay, with which gravel is
naturally combined; the latter, generally speaking, pos-
sesses little power of absorbing water, but the superabun-
dant chalk would soon be reduced to the state of a soft
paste by the action of the weather, in the manner which
we have just described. Chalk, therefore, if used as a bind-
ing material with gravel on the surface of roads, should he
reduced to a state of powder, and should he perfectly and
thoroughly mixed with the gravel before the latter is spread
on the road.
We would also remark here, that, although we have re-
commended the use of bushes or bundles of faggots, to form
the foundation of roads over very soft or boggy ground,
they should only be employed in such situations, and at
such a depth below the surface, as will ensure their always
being damp; for when in a situation where they would be
alternately wet and dry, they would quickly become rotten,
and form a soft stratum beneath the road.
CHAPTER IY.
ON EEPAIBING AND IMPBOVING EXISTING BOADS.
The improvement of existing roads may be divided into
two distinct branches; namely, the improvement of their
general course and levels, and the improvement of the ma-
terials of the road. The first of these consists in the
application of the principles which we have laid down forOIT BEPAIBIKG AOT IMPBOYIKG BOADS.
105
the construction of new roads to the altering of those
already existing, and consists generally in straightening
their course by avoiding unnecessary curves and bends;
improving their levels by either avoiding or cutting down
hills, and embanking valleys ; increasing their width, where
requisite, and rendering it uniform throughout. As these
principles are the same in both cases, and their application
has been already explained at length, it will be unnecessary
to recapitulate them here.
It is to the second class of improvements that we are
about to direct attention; namely, that of the surface of
the road ; and this consists in bringing its transverse
section to the form which we have shown in fig. 9, page 86,
filling up all ruts, cleansing and deepening, if necessary,
the side ditches, cutting down trees or hedges by the side
of the road, removing mud-banks which but too often exist
on the road-sides, and putting proper materials on its
surface.
Of all these, the most important to explain, because the
most difficult to effect, and the least generally understood,
is the method by which to improve the condition of the
surface of the road. With most surveyors the universal
remedy for a bad road is to heap on fresh material; whereas,
as Mr. M‘Adam has very justly observed,* “ Generally, the
roads of the kingdom contain a supply of materials suf-
ficient for their use for several years, if they were properly
lifted and applied.” Generally speaking, the cause of bad
roads is their imperfect transverse form, and the improper
manner in which the road materials are used. The re-
medial measures to be adopted must, in a great degree,
depend upon the nature of the materials composing the
upper surface of the road; but, whatever these may be, the
road must be brought to the proper form of section before
much improvement can be expected. This should be done
by cutting down those parts which are too high, and rais-
ing the depressed parts; where, however, the surface of
£ 3
Parliamentary Report, 1819, p. 21.106
OK EE PAIRING AND IMPROVING ROADS.
the road is so rotten or brittle that the materials so taken
off are not fit to be again used this may be done gradually,
and rather by the addition of fresh material to the lowest
parts. Unless the materials of which the road has been
formed are found to be thus brittle or rotten, or to be
already very thin, the course to be pursued is that which is
technically termed lifting the road, which consists in loosen-
ing and turning the surface of the road to a depth of about
four inches, and carefully removing such portions of the
materials as may be found in an improper state; such
as large stones, which should be broken into pieces of
the proper dimensions, and then restored to the road.
Where, however, the materials of the road are of such a
nature that in lifting they would crumble or fall to powder,
a different mode of proceeding must be adopted; in this
case we must carefully cleanse the surface of the road, from
all mud and dirt, after which fresh material, prepared as
we have described in the preceding chapter, should be laid
on in a very thin coat, never exceeding at one time three
inches, and, under ordinary circumstances, not more than
two inches in thickness. Where the surface of a road,
although hard, is found to be very thin, instead of lifting
the old materials, it will be requisite to add a fresh coat,
preparatory to doing which it would be well just to loosen
the surface of the road with a pick, so that the new mate-
rial may become more rapidly incorporated with the old
road.
The best time of the year for repairing roads is in the
autumn, when the roads are in a wet state, as the depressed
and soft parts of the road are not only then more readily
detected, but the surface of the road is then softer, and the
new materials are more easily worked into it. As we
before observed, the quantity laid on at one time should
never exceed three inches in depth, and, generally speak-
ing, a half, or even a third, of this thickness would suffice,
if judiciously employed. It is certain that more roads are
spoilt from having too much material put upon them than
there are from having too little. On this subject Mr. Pen-OK REPAIRING AND IMPROVING ROADS.
107
fold, whose experience in road-making cannot be questioned,
remarks:—“ It is one of the greatest mistakes in road-
making that can be committed, to lay on thick coats of
materials, and when understood, will be no longer resorted
to. If there be substance enough already in the road, and
which, indeed should always be carefully kept up, it will
never be right to put on more than a stone’s thickness at a
time. A cubic yard, nicely prepared and broken, as before
described, to a rod superficial, will be quite enough for a
coat, and, if accurately noticed, will be found to last as long
as double the quantity put on unprepared and in thick
layers. There is no grinding to pieces when so applied;
the angles are preserved, and the material is out of sight
and incorporated in a very little time. Each stone becomes
fixed directly, and keeps its place; thereby escaping the
wear and fretting which occur in the other case.” *
We have mentioned above, that the most proper time for
repairing roads is in the autumn; it must not, however, be
supposed that it is only at this season that roads require to
be repaired; they should, so to speak, be always under
repair: every road should be divided into lengths, on each
of which an intelligent labourer, who thoroughly under-
stands his business, should be placed, to attend constantly
and at all times to the proper state of the road, and for
which he should be responsible. His office would consist
in keeping the road always scraped clean and free from
mud, in filling any ruts or hollow places, the moment they
appeared, with broken stone’s, which should be kept in
depdts or recesses formed on the sides of the road, and one
of which should be provided in each quarter of a mile.t
Each man should be provided with a wheelbarrow, a shovel,
a pickaxe, and a scraper; each of these, and the other tools
and implements requisite for the formation or repair of
* A Practical Treatise on the best Mode of Making and Repairing Roads,
p. 15.
+■ These Depots should be capable of containing about 30 cubic yards of
material, and are beat when the sides are formed with walls, so that the
quantity of material in them can be easily ascertained.108
ON EEPAIEING AND IMPEOYING EOADS.
roads, will be hereafter described. As the autumn ap-
proached, when more had to be done to the road, additional
labourers should be engaged to assist; but the constant
labourers would be alone responsible for the good order of
the road, and the others would act under their direction.
It might be supposed that the system here proposed, of
keeping men constantly and permanently to look after
the roads, would be attended with great and unnecessary
expense; but this opinion will not be held by those who
have tried the two methods ; it will be found in this, as in
most other cases, that the old adage is true, which asserts
that “ prevention is better than cure ;” it is vastly cheaper
to prevent a road from getting out of repair, than it is to
restore it again to a proper state.
Not only should the mud formed in wet weather be care-
fully scraped off from its surface to the sides, and removed
altogether as soon as it becomes sufficiently solid, but in
dry weather the roads should be constantly and regularly
watered. In recommending this, we are not considering
the comfort of passengers using the road, although that
alone would be a sufficient reason, but on account of the
road itself. After a long season of drought, the surface of
roads becomes, as it were, baked i and in this state, being
brittle, would quickly be injured and worn to dust by con-
stant traffic; a regtdar and moderate supply of water, how-
ever, entirely obviates this, and preserves the road in a
proper state. Care should* however* be taken that the
water is properly applied, as much injury might be done by
discharging the water, either in too great quantity, or not
evenly distributed; the manner in which the water should
be poured upon the road should resemble, as nearly as pos-
sible, a gentle shower of rain. The system of watering
roads in particular states, even in winter, has been prac-
tised with advantage, as the following extract from the
evidence of Mr. Benjamin Earey, surveyor of the White-
chapel-road, before the Committee of the House of Com-
mons, will show:—“ The wheels stick to the materials, in
certain states of the road, in spring and autumn, when it isFig. 13.

Side Drain,
§
o
«o
CTi
2110
ON REPAIRING AND IMPROVING ROADS.
between wet and dry, particularly in heavy foggy weather,
and after a frost; by which sticking of the wheels the
Whitechapel-road is often, in a short time, dreadfully torn
and loosened up; and it is for remedying this evil that I
have, for' more than eight years past, occasionally watered
the road in winter. As soon as the sticking and tearing-up
of the materials is observed to have commenced, several
water-carts are employed upon these parts of the road, to
wet the loamy and glutinous matters so much that they
will no longer adhere tb the tire of the wheels, and to allow
the wheels and feet of the horses to force down and again
fasten the gravel-stones ; the traffic, in the course of four
to twenty hours after watering, forms such a sludge on the
surface as can be easily raked off by wooden scrapers,
which is performed as quickly as possible; after which, the
road is hard and smooth: the advantages of this practice of
occasional winter-watering have been great; and it might,
I am of opinion, be adopted with like advantages on the
other entrances into London, or wherever else the traffic is
great, and the gravel-stones are at times observed to be
torn up by the sticking of the wheels.”#
We shall next proceed to a description of the ^
tools or implements employed in the construc-
tion and repair of roads. The most important
of these is the level used for forming the true
transverse section of the road. It is shown in
figure 13, and consists of a horizontal straight-
edge or bar A c, having in the center of its
length a plummet b d, for ascertaining when
the straightedge is horizontal. Thus far it ex-
actly resembles an ordinary bricklayer’s level.
A line is drawn near the end A of the bar, and
at every four feet from this line a gauge (a, b,
c, dy) is fixed in a dove-tailed groove, in such
a way as to be capable of being moved up or
down, so as to adjust the depth of its lower end
below the horizontal line of the bottom of the straightedge;
# Parliamentary Report, 1819, p. 40.
iON EEPAIBING AND IMBBOVING BOADS.
Ill
and there are thumb screws (one of which is shown on an
enlarged scale in figure 14) passing through each gauge, by
tightening which the gauge can be fixed when so adjusted.
When the bottoms of the gauges a9 b, c, and d, have been
adjusted as shown in fig. 13, they will coincide with the
surface recommended to be given to a road 30 feet in
width, and such as we have shown in fig. 9; and, in
order to ascertain whether the surface of any existing
road is constructed to the proper inclination and form,
it is only requisite to«apply the level, which, when placed
perfectly horizontal, by means of the plummet b d, should
rest upon the road at the lower extremity of each of
the gauges a, b, c, and d. For forming the sides of
roads of greater width than 30 feet, it would be convenient
to have a level constructed in the manner shown in fig. 15,
in which A b is a straightedge about 15 feet long, having in
the center of its length a plummet c d, so adjusted that
when hanging truly in its place, the lower side of the
straightedge should be inclined from a horizontal line
at the rate of 1 in 30.
The jpiclc used for lifting the surface of Fig. 16.
roads is shown in fig. 16. The bent iron
head a b should weigh about ten pounds,
haying a large eye in the center (c), in which
is fitted the handle, which should be of ash,
rather more than two feet in length; one
extremity a should be tformed like the end
of a chisel, while the other b should termi-
nate in a blunt point. Both ends should «'
be tipped with steel.112
ON REPAIRING AND IMPROVING ROADS.
3Tig. 17. The most useful form of shovel for road
purposes is shown in fig; 17. The blade
should he somewhat pointed, and the handle
bent, so as to enable the person using it to
bring the blade flat upon the surface of the
road without excessive stooping.
The ordinary wheelbarrows are of ash or
elm, with cast-iron wheels ; but it would be
an advantage if wheelbarrows for road pur-
poses were made of wrought iron, which
would combine strength and durability with
lightness. Of whatever material, however,
they are constructed, they should not ex-
ceed nine inches in depth, and their sides
| should be splayed with a slope of 2 to
1. It would be also very desirable to have
hooks placed on their sides to receive a
sh’ovel and pick.
The screens, or sieves, employed for sepa-
rating the coarse gravel from the hoggin or small gravel,
consist of iron wires or slender rods, placed at equal dis-
tances apart, and fixed in a frame of wood, the sides of
which are raised about five inches above the plane of the
wires. In the screens the frames are rectangular, about 5
feet 6 inches in height and 3 feet wide, and the wires are
stretched in the direction of its length at distances varying
from half an inch to an inch and a quarter, according to the
size of the stone required; and these wires are kept in
place by others crossing them at intervals of five or six
inches. When used, they are placed so that the plane of
the wires is inclined about 30° from the upright, and the
gravel to be screened being dashed or thrown forcibly
against them, the finer particles pass through and fall on
the further side of the screen, while the large stones roll
down its surface and fall on the nearest side. The sieves
are somewhat different in form, the frame being circular,
forming a cylinder about 6 inches in depth and 20 inches in
diameter, the wires being placed either as we have alreadyOK BEPAIEIKG AKD IMPBOYIKG EOADS. 113
Tig. 18.	I'm. 19.	I’m. 20.
14 inches.114
OK BEPAIBIKG AKD IMPBOVIKG BO ADS.
described or equally close in both directions, and forming a
kind of bottom to the cylinder. The sieve is held hori-
zontally by one man, while the other throws into it a
shovelful of gravel; upon shaking the sieve the fine hoggin
falls through, leaving the stones in the sieve, which are then
thrown by the man into anything which may be placed to
receive them. The latter is generally the best and cheapest
mode of screening gravel.
The hammers generally employed for breaking stones
are of two sizes, and are shown in figs. 18 and 19. The
handles should be of straight-grained ash, and the iron
heads of the weight and form shown in the drawings ; the
faces should be spherical, and case-hardened or steeled.
Fig. 20 represents the ring to be used for testing the
size of the broken stones. Its internal diameter is 21-
inches, and the largest stones should be able to be passed
through the ring in every direction.
Fig. 21 represents a pronged forJc, to be used instead of
a shovel for taking up the stones to throw upon the road.
The advantages attending its use are, that a man can take
up the stones much quicker and easier than with a shovel,
and free from all dirt and extraneous matter, which, in the
case of broken angular stones, is of importance.
It is sometimes advantageous to roll the surface of new
roads, in order to consolidate the material, and for this
purpose a cast-iron roller is usually employed, about five
feet wide, four feet in diameter, and weighing about four tons.
The rakes, which should be employed in filling in ruts
and hollow places in the surface of roads, should be formed
with prongs between 2 and 3 inches in length, fixed at the
distance of three-quarters of an inch apart, into a wooden
head about 11 inches in length. Their handles should be
formed of ash, and should be about six feet in length.
Scrapers are indispensable for preserving roads in a
proper state and free from mud. They are usually con-
structed of wood shod with wrought iron, but it is much
beti er to make them entirely of iron. They should be 6
inches in depth, and about 18 inches in length, and slightlyOK HEDGES AKD FEKCES.
115
curved at each extremity to prevent the escape of mud at
each side.
Scraping Machines have been invented, and are very
generally employed, by means of which the surface of a road
may be scraped much more regularly and quickly than
with the old scrapers. They consist of a number of
iron scrapers, attached to a frame mounted on wheels,
which are so placed that, when the body of the machine is
raised somewhat, the wheels are lifted from the ground,
and the whole weight of the machine is thrown upon the
scrapers, which, upon the machine being drawn across the
road, scrape all the mud from its surface, and carry it to
the sides.
A machine has also been invented by Mr. Whitworth, of
Manchester, which has been extensively employed both at
that place and in London, for sweeping up the mud from
the roads and carrying it away at once. It consists of a
species of endless broom, passing round rollers attached to
a mud cart, and so connected by cogged wheels with the
wheels of the cart that, when the latter is drawn forwards,
the broom is caused to revolve, and sweeps the mud from
the surface of the road up an inclined plane into the cart.
The machine is drawn by one horse; and by its aid the
roads are swept much more rapidly and better than by the
old system of scraping, and with far less injury to the sur-
face of the road and annoyance to the passengers.
CHAPTER V.
OK HEDGES AKD FEKCES.
Ik most situations fences of some description are re-
quired to mark the boundaries of roads, and separate
them from the adjoining lands. They should, however,
always be dispensed with wherever it is possible to do so,116
Off HEDGES AffD EEffCES.
for the reason, that all fences, of whatever kind, to a
greater or less extent deprive the surface of the road of a
free exposure to the action of the wind and sunshine, both
of which are essential to maintain it in a dry state. Few
persons are aware of the extent to which a road may be
injured by being fenced in with high hedges, or lined with
trees; the latter are worse even than hedges, because they
not only shelter the road from the effects of the air and
sun, but further injure it by the drippings of rain which
fall from their leaves, and retain the road in a wet state
long after it would otherwise have become dry.
Where fences are indispensable, they should therefore
be kept as low as possible, and thrown as far as they can
be from the sides of the road. When the road has a deep
ditch on either side, it then becomes necessary, to prevent
accidents, that the fence should be placed between the road
and the ditch ; but in all other situations the fence should
be placed on the field side of the ditch; for the double
reason, that in so doing the surface drainage of the road
into the side ditches is less interfered with, and that the
road is then not so much sheltered by the fence itself.
The different descriptions of fence which may be em-
ployed are very various; in districts where stone is plen-
tiful, and especially in the immediate neighbourhood of
the quarries, where stone rubble can be obtained at a
trifling cost, dry walls built of this description of stone,
without any mortar, are very good and cheap, and when
once built require little or no repairing.
As far as the road itself is concerned, an open post-and-
rail fence is the best which can be employed, because it
scarcely impedes the action of the wind and sun upon the
surface of the road; but the great practical objection to
a timber fence of any description is, its liability to decay,
which occasions a frequent and constant expense to be
incurred in its renewal.
The most general, and, all things considered, the most
useful, fence is the quickset hedge : and, if properly planted,
and carefully attended to for the first few years, a naturalON HEDGES AND FENCES.
117
fence may thus be obtained, sufficiently strong to resist
the efforts of every description of cattle to get through it,
and to maintain which hut a very small annual sum will be
requisite, A bank or mound of earth, at least two feet
in depth, should be prepared for the reception of the
quicks, which should be three-years plants which have been
transplanted two years. The best description of soil is one
of a light sandy nature, which will admit sufficient moisture
to nourish the plants, aud retain a portion even in dry
seasons. Heavy clay soils are not sufficiently pervious to
water, and plants placed in such soils are never found to
thrive. A mixture of peat or rotten leaves is of great use,
and causes the plants to grow with much vigour. The
most usual way is, to plant the quicks in a single row, at
distances of about four inches apart. But a much better
hedge is formed by planting them in a double row, as
shown in fig. 22, with a space of six inches between the
two rows, and the plants the same distance apart in each
Fig. 22.
O O O O o
o 0 O o o o
row, and so arranged that the plants in one row are oppo-
site the spaces in the other. By this arrangement,
although the plants are really not so crowded, but have
more space round their roots from which to derive nou-
rishment, they form a thicker hedge. The proper time for
planting quicks is either during the autumn or spring, and
in fine seasons the operation may be continued during the
whole winter. A temporary fence should be put up to pro-
tect the young plants from injury, or from having the
shoots eaten off by cattle; and this fence should be kept up
until the hedge has attained sufficient strength to require
its protection no longer, which, under favourable circum-
stances, will be in about three or four years after the
quicks have been planted. In order that the plants
should thrive, they must be very carefully attended to at118
ON PAVED ROADS AND STREETS.
first, and it is essential that they should be properly cleaned
and weeded at least twice every year; and once every
year, towards the conclusion of the summer, the hedge
should he judiciously trimmed, not to such an extent as to
produce stunted plants, but merely cutting off the upper
and more straggling shoots, so as to bring it to a level and
even surface: by proceeding in this manner, in about
three years after planting, a neat, strong, and compact
hedge of healthy plants will be obtained.
When the hedge or fence is placed between the road and
the side ditches, it is essential that small drains be formed
at least every fifteen yards, to convey the water from the
side tables or gutters through the fence into the ditches.
CHAPTEB VI.
ON PAVED ROADS AND STREETS.
In constructing roads, or rather streets, through towns or
cities, where the amount of traffic is considerable it will be
found desirable to pave their surface. The advantages be-
longing to pavements in such situations over macadamised
roads are considerable; where the latter are exposed to an
incessant and heavy traffic, their surface becomes rapidly
worn, rendering constant repairs requisite, which are not
only attended with very heavy expense, but also render the
road very unpleasant for being travelled upon while being
done; they also require much more attention in the way of
scraping or sweeping, and in raking-in ruts. And some
difficulty would be experienced in towns to find places in
which the materials, which would be constantly wanted for
repairing the road, could be deposited. In dry weather
the macadamised road would always be dusty, and in wet
weather it would be covered with mud. The only advan-
tage which such a road really possesses over a pavement is,
the less noise produced by carriages in passing over it; butQN PAVED EOAD8 AND STEEETS.	.	119
this advantage is very small when the pavement is properly
laid.
In laying pavements, as in forming roads, the first and
one of the most important objects should be, to obtain a
firm and unyielding foundation. It should be borne in
mind, that the pavement itself, whatever may be its thick-
ness, and however carefully and closely the stones of which
it is composed may be fitted together, must be entirely in-
adequate to support the heavy load to which all roads are
occasionally exposed; and unless the foundation beneath
the pavement is sufficiently firm to support these loads it-
self, the pavement will subside, and its surface soon become
uneven. The real object of paving is nothing more than
to give to the road a hard surface, not so liable to wear as it
would itself be.
Several different methods have been employed of forming
the foundations of pavements, such as concrete and broken
stone ; but where it can be done, it is perhaps best to lay
the new pavement on the old surface of the road, whether
paved or macadamised, taking care of course that its sur-
face has been brought first to an even state, and of the
required form of cross section.
The practice of laying the new pavement on the top of
the old has been a great deal used in Paris, and has there
been found to answer extremely well. It is usual to take
up and relay the old pavement, in order that its surface
may be even and true, after which it is just covered with
gravel, on which the new stones are bedded. Mr. Telford
strongly recommended the surface upon which the pave-
ment was intended to be laid to be prepared as though in-
tended for a macadamised road, and, in that state, that it
should be used by carriages until it had become thoroughly
consolidated, when the pavement should be laid on the top
of the hard road so formed, the stones being properly
bedded in a kind of coarse mortar; and Mr. Edgeworth, in
his work on roads, states that this method of forming paved
roads had been extensively employed in Dublin, and had
been found to be attended with considerable success.120	Off PAYED BO ADS AND STBEETS.
In cases, however, in which it would not be practicable
to lay the new pavement upon the surface of the existing
road, the following method should be employed for forming
a good foundation. The loose ground at the surface should
first be entirely removed; the depth to which it may be
requisite to do this must depend upon the nature of the
ground itself; unless the ground be very solid, it should be
removed to such a depth as will allow of 18 inches of con-
crete being put in beneath the pavement. In some situa-
tions so great a thickness as this may not be requisite, but
it is much better, and in the “long run” much cheaper,
to err rather in forming too strong a foundation, than one
the failure of which necessitates the taking up and relaying
of the pavement. As soon as the loose ground has been
removed, a layer of concrete, prepared in the manner
already described at page 96, should be evenly spread
over the whole area of the intended road: its depth, as
before remarked, must depend on the nature of the sub-
soil, and the extent of traffic to which the road will be
exposed; it should never, however, be less than 12 inches,
and, under ordinary circumstances, not less than 18 inches.
Its upper surface should be formed to the true form of
cross section intended to be given to the road, which
should under no circumstances be greater than that already
recommended at page 86 to be given to the surface of
common roads, and in most cases a less inclination would
be found sufficient and preferable.
The stones should be well bedded upon the concrete in
a kind of coarse mortar, which should also be well filled in
between their joints.
With regard to the stone to be employed for this pur-
pose, several of the harder kinds are used, such as granite,
whinstone, limestone, and freestone; of these two last,
however, only the very hardest varieties should be used.
Of all materials granite is the best, and more particularly
those kinds, such as the Guernsey and Aberdeen, whi^h do
not wear smooth and acquire a polished surface, which is a
great practical defect attending the employment of exces-ON PAYED ROADS AND STREETS.
121
sively hard stone. With regard to the form of the stones,
experience has shown that the best is that of rectangular
blocks, from 8 to 15 inches in depth (depending on the
amount and nature of the traffic), about 18 inches in length,
and not more than 3 or 4 inches in width. Until lately it
was considered better to have stones of much greater
width, under the supposition that having a larger base
they would be better able to support the superincumbent
weight, but experience has shown that the narrow stones
are by far the best. Great care should be taken in sorting
the stones according both to their depths and widths: for
if the stones are of unequal depth, and the surface of the
concrete has been made, as it should be, even and parallel
to the intended surface of the road,
any stones less than the general Ym. 23.
depth would require more mortar to	|--1----1--1----j
be placed under them, and would	\	|	|	\	]
consequently settle down more than	1	1	1	! I
the others, and form hollows on the	I	_ 1	1	t I	~1
surface of the road. They should	*--1----L--1—J
also be sorted according to their
width, so that they may run entirely across the street in
parallel courses, as shown in fig. 23, and the stones in each
course should be so selected as to break joint with those
in each adjoining course, as there shown.
It is essential to the formation of a good pavement that
a firm and substantial curb should be well laid on each side
of the road, for it to abut against; and in laying the pave-
ment the courses should be commenced at each side, and
worked towards the center; the joints between the stones
should be as thin as possible, and the last stone should fit
tightly, so as to form a kind of key to the whole. After
the stones have been set they should be well rammed down
with a heavy punner, and any stone which went down
below the general level should be taken up, and packed
underneath. It is not usual to go to the expense of bed-
ding the stones in mortar in the manner here recommended,
but only to pour a thin grouting of sand and lime over the122
OK PAYED BOADS AKD STREETS.
surface, after the pavement has been laid, which finds its
way, although very imperfectly, into the interstices be-
tween the stones. It is, however, a mistaken economy,
as a pavement laid as here described upon a firm concrete
foundation, and having the joints perfectly formed with
good mortar, would last almost for ever, since nothing less
than the positive wearing away and destruction of the stone
would render its renewal necessary.
Some little attention is necessary to be given to paved
roads for a few months after being opened for traffic, in
order to prevent irregular settlement in the stones, and
consequently an uneven and irregular surface. The mo-
ment any portion of the road is found to settle below the
general level it should be taken up, and a sufficient quan-
tity of fine concrete put underneath it to bring it again
slightly above the level of the remainder. Great attention
should also be paid to the manner in which the pavement
is re-laid after being disturbed for the repair of sewers or
water and gas pipes; the excavated ground, when thrown
back, should be well punned, or beaten down in layers of
not more than a foot in thickness, and at least 18 inches
of concrete should be laid on the top, under the pavement;
the surface of this concrete should be about an inch above
the general level, and the stones should be properly bedded
in the manner already described, care being taken that the
stones correspond in depth and width with those already in
place on either side, and furthermore that the last stone,
in making good each course, fits tightly into its place.
In laying pavement in streets having Fin.
a considerable inclination, two methods
have been employed to afford a more
sure and perfect hold for the horses’
feet than the ordinary pavement. The
first method is shown in fig. 24, and
consists in laying between each row of
paving-stones a course of slate, rather
less than an inch in thickness, and to about the same extent
less in depth than the stones themselves. By this means
Big. 25.ON PAVED ROADS AND STREETS.
123
a series of small channels or grooves, about an inch in
width and depth, are formed between each row of stones,
which afford sufficient stay for the horses* feet; this me-
thod has been adopted in Tooley-street, Southwark. The
other method is somewhat simpler, and consists in merely
placing the ordinary paving-stones somewhat canted on
their beds, as shown in fig. 25, so as to form a series of
ledges or steps, against which the horses* feet being planted,
a secure footing is obtained.
Of late years wood has been introduced as a material
for paving streets, and has been rather extensively em-
ployed both in Russia and America. It has been tried in
various parts of London, and generally with small success,
the cause of its failure being identical with the cause of
the enormous sums being spent annually in the repairs of
the streets generally, namely, the want of a proper founda-
tion ; a want which was sooner felt with wood than with
granite, in consequence of the less weight and inertia of
the wood. The comfort resulting from the use of wooden
pavement, both to those who travelled, and those who lived
in the streets, from the diminished jolting and noise, was
so great, that it is just matter of surprise that so little care
was taken in forming that which a very little considera-
tion would have shown to be indispensable to its success,
namely, a good foundation. Slipperiness of its surface, in
particular states of the weather, was also found to be a
disadvantage belonging to wooden pavement, but means
might be devised which would render its surface at all
times safe, and afford a secure footing for horses. As re-
gards durability, it has scarcely been used for a sufficient
period to allow a comparison being made with other mate-
rials, but from the result of some observations communi-
cated by Mr. Hope to the Scottish Society of Arts, which
are given by Mr. Leahy in a note at page 76 of his work
on roads, it appears that wooden blocks when placed with
the end of the grain exposed, wear less than granite. At
first sight this result might appear questionable, but it is
a well-ascertained fact that, where wood and iron move in
p 2124 ON TAKING OUT QUANTITIES EOB ESTIMATES.
contact in machinery, the iron generally wears more rapidly
than the wood, the reason appearing to be, that the surface
of the wood soon becomes covered with particles of dust
and grit, which become partially embedded in it, and, while
they serve to protect the wood, convert its surface into a
species of file, which rapidly wears away whatever it rubs
against.
CHAPTER VII.
ON TAKING OUT QUANTITIES FOB ESTIMATES.
Tiie operation of making out an estimate for any descrip-
tion of engineering work may be divided into two distinct
parts: namely, in the first place, calculating the actual
quantity of each description of work to be executed; and,
in the second place, affixing to these quantities just and
reasonable prices, such as the work might really be exe-
cuted for.
It is only upon the first of these, namely, taking out the
quantities, that we propose to speak here; not that the
other is the less important, but because it would be difficult
to lay down any principles for priceing work, or to fix any
standard prices, without the probability of leading to erro-
neous results. The cost of different descriptions of work
depends upon so many varying circumstances, and is af-
fected so greatly by the nature of the locality, that it would
be impossible to give any standard prices. The surest
method to obtain correct information on this matter is, by
inquiries as to the usual cost of such work in the particular
locality itself.
In the construction of roads, the principal item of ex-
pense is the earthwork, or the cost of forming the cuttings
and embankments to obtain the required levels for the
formation surface, in excavating the ditches and formingOK TAKING OUT QUANTITIES- FOB ESTIMATES. 125
the banks, and in laying on the metalling or ballast to form
the road. Of all these different descriptions of work, the
first, namely, the cuttings and embankments, are the only
ones the estimation of the quantity of which is attended
with any difficulty. The others, being generally constant,
are readily obtained by ascertaining the quantity in a given
length, as a yard, and then multiplying that quantity by
the total length of the road.
In estimating the cubic content of any cutting or em-
bankment, the operation will be simplified by considering
the slopes apart from the trunk or main body of the cut-
ting. Tor example, let fig. 26 be the section of a cutting,
A d being the natural surface of the ground; then if b c is
the width of the formation surface, bcpe will be the trunk
br central portion of the cutting, and AEB,rcD, will be
the side slopes. Now the width of the first is constant,
being the formation width, while its depth varies as the
depth of the cutting; and therefore its cubic content for a
given length forward is directly proportional to the depth of
the cutting. If, for instance, the line g h were the natural
surface of the ground instead of a d, the cutting being now
twice as deep as before, the cubic content of the trunk
I b o k would be twice as great as that of ebcp. The
cubic content, however, of the slopes increases in the pro-
portion of the square of the depth of the cutting, as is evi-
dent from the figure, in which I B being twice as great as
E B, the slope g i b is four times as great as A E B, the
triangles a, b9 c, and d being evidently equal. It is in con-
sequence of these two quantities varying in a different pro-126 ON TAKING OUT QUANTITIES FOB ESTIMATES.
portion that it is found convenient to estimate them sepa-
rately. In order to facilitate the calculation of earthwork,
several tables have been published, the most complete and
elaborate of which are those by Sir John Macneill. The
following table will be found very useful in estimating the
content of cuttings or embankments of moderate depth,
and will give the result very nearly true, except in cases in
which the two ends of the cutting are of very different
depths. The first, fourth, and seventh columns contain the
depth of the cutting or height of embankment, in feet, for
every tenth of a foot, from OT to 25*2 feet; the second,
fifth, and eighth columns express the content, in cubic
yards, of one foot in width, and one chain in length, of a
portion of the trunk or central part of a cutting, whose
mean depth is shown in the preceding column. The quan-
tities taken from these columns must be multiplied by the
formation width. The third, sixth, and ninth columns ex-
press the content in cubic yards of a length of one chain of
both slopes, when the slopes are formed at 1 to 1. "With
any other ratio the quantities derived from these columns
must be increased in the same proportion. Thus, if the
slopes are 3 to 1, the quantity obtained from the table
must be multiplied by 3.OK TAKING OUT QUANTITIES TOE ESTIMATES. 127
Height or depth.	Content for a length of one chain.		Height or depth.	Content for a length of one chain.		Height or depth.	Content for a length of one chain.	
	Of each foot in width of trunk.	Of slopes taken at 1 to 1.		Of each foot in width of trunk.	Of slopes taken at 1 to 1.		Of each foot in width of trunk.	Of slopes taken at 1 to 1.
Feet	Cab. yds.	Cub. yds.	Feet.	Cub. yds.	Cub. yds.	Feet.	Cub. yds.	Cub. yds.
0*1	*24	*02	4*3	10*51	45*20	8-5	20*78	176-6
0-2	•49	•10	4*4	10*76	47-32	8-6	21*02	180-8
0*3	•73	•22	4*5	11-00	49-50	8-7	21*27	1850
0*4	•99	•39	4-6	11*24	51*7*2	8*8	21*50	189-3
0*5	1*22	*61	4*7	11-49	54-10	8*9	21-76	193-6
0*6	1*47	*88	4-8	11-73	56-42	90	2200	1980
07	1-71	1*20	4-9	11-98	58-79	9*1	22*24	202-4
0*8	1*96	1*56	5-0	12-22	61*11	9*2	22*49	206*9
0-9	2*20	1*98	5-1	12-47	63-58	9-3	22-73	211*4
10	2*44	2-44	5-2	1271	6610	9*4	22-98	216-0
1*1	2*69	2-96	5-3	1296	68-66	9-5	23-22	2206
1*2	293	3*52	5-4	13 20	71*28	9*6	23*47	•225*3
1*3	3*18	413	5*5	13*44	73-94	9*7	23-71	2300
1*4	3*42	4*79	5*6	13*69	76*66	9*3	23*96	234*8
1-5	3*67	550	5*7	13*93	79*42	9*9	24-20	239-6
1*6	3*91	6*26	5-8	14*18	82*23	10-0	24*44	244*4
17	416	7*06	5-9	14-42	8509	10*1	24*69	249*4
1-8	4*40	792	60	14-67	8800	10-2	24*93	254*3
1*9	4*64	8*82	6*1	14-91	90-96	10-3	25*18	259*3
20	4*89	9-78	6-2	15*16	93-96	10*4	25*42	264-4
21	513	10-78	6-3	15*40	97*02	10*5	25*67	269-5
2*2	5*38	11*83	6-4	15-64	100-1	10-6	25*91	274*6
2-3	5*62	12-93	6-5	1589	103-3	10*7	2616	279-9
2*4	587	14*08	6*6	16-13	106-5	10*8	26*40	285*1
2-5	611	15-28	6-7	16*38	109*7	10*9	26*64	290*4
2-8	6*36	16*52	6-8	16*62	113*0	11*0	26-89	295*8
2*7	6*60	17*82	6-9	16-87	116-4	11*1	2713	301*2
2*8	6*84	1916	7*0	17*11	119*8	11*2	27*38	306*6
2-9	7-09	20-56	7*1	17*36	123-2	11*3	27*62	3121
30	7*33	2200	7-2	17-60	126*7	11*4	27*87	317*7
3*1	7*58	23-49	7*3	17*84	130*3	11*5	28-11	323-3
3*2	7*82	2503	7*4	18*09	133*8	11*6	28-36	328-9
3-3	807	2662	7*5	18-33	137*5	11*7	28-60	334*6
3*4	8*31	28-26	7*6	18-58	141*2	11-8	28-84	340*4
3*5	856	29-94	7-7	18-82	144*9	11*9	2909	346-2
3*8	8*80	31*68	7*8	1907	148-7	12*0	29-33	3520
3*7	9*04	33*46	7-9	19-30	152-6	12*1	29*58	3579
3*8	9*29	35*30	80	19-56	156*4	12*2	29-82	363-8
3*9	9*53	37*18	8*1	19*80	160-4	12-3	30-07	369*8
4*0	9*78	39*11	8-2	20-04	164-4	12*4	30*31	375*9
4*1	1002	41*09	8-3	20*29	168*4	12*5	30*56	381*9
4*2	1027	43*12	8*4	20-53	172*5	12-6	30*80	388*1128 ON TAKING OUT QUANTITIES FOB ESTIMATES.
Height or depth.	Content for a length of one chain.		Height or depth.	Content for a length of one chain.		Height or depth.	Content for a length of one chain.	
	Of each foot in width of trunk. 1	Of slopes taken at 1 to 1.		Of each foot in width of trunk.	Of slopes taken at 1 to 1.		Of each foot in width of trunk.	Of slopes taken at 1 to 1.
Feet.	Cub. yds.	Cub. yds*	Feet.	Cub. yds.	Cub. yds.	Feet.	Cub. yd*.	Cab. yds.
12*7	31*04	394*3	16*9	41*31	698*2	21 *1	51*58	1088
12*8	31*29	400 5	17*0	41*56	706*4	21*2	51*82	109.9
12*9	31*53	406*8	17*1	41*80	714*8	21*3	5207	1109
13*0	31*78	413*1	17*2	42*04	723*2	21*4	52*31	1119
13*]	32*02	419*5	17*3	42*29	731*6	21*5	52*56	1130
13*2	32*27	425*9	17*4	42*53	740*1	21*6	5*2*80	1140
13*3	32*51	43*2*4	17*5	42*78	748*6	21*7	53*04	1151
13*4	32*76	438*9	17*6	43*02	757*2	21*8	53*29	1162
13 5	3300	445*5	17-7	43*27	765*8	21*9	53*53	1172
13*6	33*24	452-1	17 8	43*51	774*5	22*0	53*78	1183
13*7	33*49	458*8	17-9	43*76	783*2	22*1	54*02	1194
13*8	33*73	465*5	18*0	44*00	792*0	22*2	54*27	1205
13*9	33*98	472*3	18*1	44*24	800*8	22*3	54*51	1216
140	34*2*2	479*1	18*2	44*49	809*7	22*4	54*76	1227
14*1	34*47	486*0	18*3	44*73	818*6	22*5	5500	1238
14-2	34*71	492*9	18*4	44*98	827*6	22*6	55*24	1249
14*3	34*96	499*9	185	45*22	836*6	22*7	55*49	1260
14*4	35*20	506*9	18*6	45*47	845*7	22*8	55*73	1271
14-5	35*44	513*9	18*7	45*71	854*8	2*2*9	55*98	1282
14*6	35*69	521*1	18*8	45*96	864*0	23*0	56*22	1293
14*7	35*93	528*2	18*9	46*20	873*2	23*1	56*47	1305
14*8	36*18	535*4	19*0	46*44	882*4	23*2	56*71	1316
14*9	36*42	542*7	19*1	46*69	891*8	23*3	56*96	1327
150	36*67	550*0	19*2	46*93	901*1	23*4	57*20	1339
15*1	36*91	557*4	19*3	47*18	910*5	23*5	57*44	1350
15*2	37*16	564*8	19*4	47*42	920*0	23*6	57*69	1362
15*3	37*40	57*2*2	19*5	47*67	929*5	23*7	57*93	1373
15*4	37*64	579 7	19*6	47*91	939*1	23*8	58*18	1385
15*5	37*89	587*3	19*7	48*16	948*7	23*9	58*42	1397
15*6	38*13	594*9	19*8	48*40	958*3	24*0	58*67	1408
15*7	38*38	602*5	19 *9	48*64	968*0	24*1	58*91	1420
158	38*6*2	610*2	20*0	48*89	977*8	24*2	59*16	1432
15*9	38*87	618*0	20*1	49*13	987*6	24*3	59*40	1443
16*0	39*11	625*8	20*2	49*38	997*4	24*4	59*64	1455
16*1	39*36	633*6	20*3	49*62	1007	24*5	59*89	1467
16*2	39*60	641*5	20*4	49*87	1017	24*6	60*13	1479
16*3	39*84	649*5	20*5	50*11	1027	24*7	60*38	1491
16*4	40 09	657*5	20*6	50*36	1037	24*8	60*62	1503
16*5	40*33	665*5	20*7	50*60	1047	24*9	60*87	1516
16*6	40*58	673*6	20*8	50*84	1058	25*0	61*11	1527
16*7	40*82	681*7	20*9	51*09	1068	25*1	61*36	1540
16*8	41*07	689*9	21*0	51*33	1078	25*2	61*60	1552ON TAKING OUT QUANTITIES FOB ESTIMATES. 129
As an example of the use of this table, we shall proceed
to estimate the quantities in the cutting and embankment
shown on the working section, fig. 8. In the following
table, the first column contains the number of the peg, the
second the depth of cutting or height of embankment, the
third the cubic content of the corresponding portion of the
trunk, and the fourth column the content of the slopes.
Cutting No. 1.
No. of peg.	Depth of cutting.	Trunk.	Slopes.
1	*0	*37	*11
2	•6	1-47	•88
3	*9	2*20	1*98
4	1*2	2-93	3*52
5	1*6	3*91	6*26
6	1*9	464	8-82
7	20	4*89	9 78
8	1*9	4*64	8*82
9	1-9	4*64	8*82
10	2*1	5*13	10*78
11	2*2	5*38	11*83
12	2*4	5*87	14*08
13	2*3	5*62	12 93
14	2*3	5-62	12 93
15	2*5	611	15*28
16	2*1	513	10*78
17	2*3	562	12*93
18	25	611	15*28
19	2-2	5-38	11*83
20	1-6	3*91	6*26
21	•a	1-96	1*56
		91*53 40 3661*20 185*46 3846*66 -	185*46 cub. yds.
Embankment No. 1.
ti <b	c o S		
O 6 fc	J= g 5 a % O)	Trunk.	Slopes.
22	•6	1*47	*88
23	2*2	5*38	11*83
24	3*5	8*56	29*94
25	40	9*78	39 11
26	3*8	9*29	35*30
27	2*6	6*36	16*52
28	1*3	3*18	4*13
29	•3	•73 44*75 40 1790*00 137*93 68*96	•22 137*93
		1996*89 cub. yds.	
It will be remarked that, at peg 1, where the cutting has
no depth, we haye yet inserted quantities in the third and
f 3130	PROFESSOR MAHAN’S ELEMENTARY
fourtli columns. The manner in which these were derived
is as follows. Although at the peg itself there is no cutting,
at the next peg the depth is 0*6, and therefore the mean
depth is 0*3, which, in the table, gives 0*73 and 0*22. As,
however, we have here only half a chain (as it is the com-
mencement of the section), we insert half these quantities,
or 0 37 and 0T1. The sum of all the separate portions of
the trunk, being obtained by addition, is then multiplied
by 40, the width of the formation, to which the sum of the
slopes being added, gives 3846*66 cubic yards as the con-
tent of the cutting. In the case of the embankment, the
slopes being to 1, we add one and a half times the sum
of the slopes, and thus obtain 1996*89 cubic yards as its
content. By reference to the working section, fig. 8, it
will be seen that the quantities there given agree with the
above.
CHAPTER YIII.
PROFESSOR MAHAN*S ELEMENTARY ESSAY ON ROAD-
MAKING.
In establishing a line of internal communication of any
character, whether it be an ordinary road, railroad, or
canal, the main considerations to which the attention of
the engineer must be directed in the outset are—1, the
probable character and amount of traffic over the line;
2, the wants of the community in the neighbourhood of
the line; 3, the natural features of the country, between
the points of arrival and departure, as regards their adap-
tation to the proposed communication.
As the last point alone comes exclusively within the
province of the engineer’s art, and within the limits pre-
scribed to this work, attention will be confined solely to its
consideration.
Reconnaissance.—A thorough examination and study of
the ground by the eye, termed a reconnaissance, is an in-
dispensable preliminary to any more accurate and minuteESSAY ON BOAD-MAKING.
131
survey by instruments, to avoid loss of time, as by this
more rapid operation any ground unsuitable for the pro-
posed line mil be as certainly detected by a person of
some experience, as it could be by the slow process of an
instrumental survey. Before, however, proceeding to make
a reconnaissance, a careful inspection of the general maps
of that portion of the country through which the commu-
nication is to pass, will facilitate, and may considerably
abridge, the labours of the engineer; as from the natural
features laid down upon them, particularly the direction of
the water-courses, he will at once be able to detect those
points which will be favourable, or otherwise, to the ge-
neral direction selected for the line. This will be suffi-
ciently evident when it is considered—1, that the water-
courses are necessarily the lowest lines of the valleys
through which they flow, and that their direction must also
be that of the lines of greatest declivity of their respective
valleys ; 2, that from the position of the water-courses the
position also of the high grounds by which they are separated
naturally follows, as well as the approximate position at
least of the ridges, or highest lines of the high grounds,
which separate their opposite slopes, and which are at the
same time the lines of greatest declivity common to these
slopes, as the water-courses are the corresponding lines of
the slopes that form the valleys.
Keeping these facts (which are susceptible of rigid ma-
thematical demonstration) in view, it will be practicable,
from a careful examination of an ordinary general map, if
accurately constructed, not only to trace, with considerable
accuracy, the general direction of the ridges from having
that of the water-courses, but also to detect those depres-
sions in them which will be favourable to the passage of a
communication intended to connect two main or two
secondary valleys. The following illustrations may serve
to place this subject in a clearer aspect.
If, for example, it be found that on any portion of a map
the water-courses seem to diverge from or converge towards
one point, it will be evident that the ground in the first
case must be the common source or supply of the water-
courses, and therefore the highest; and, in the second case,
that it is the lowest, and forms their common recipient.
If two water-courses flow in opposite directions from a
common point, it will show that this is the point from
ivhich they derive their common supply, at the head of132	pbofessob Mahan’s elemektaby
their respective valleys, and that it must be fed by the
slopes of high grounds above this point; or, in other
words, that the valleys of the two water-courses are sepa-
rated by a chain of high grounds, which, at the point where
it crosses them, presents a depression in its ridge, which
would be the natural position for a communication con-
necting the two valleys.
If two water-courses flow in the same direction and pa-
rallel to each other, it will simply indicate a general incli-
nation of the ridge between them, in the same direction as
that of the water-courses. The ridge, however, may pre-
sent in its course elevations and depressions, which will be
indicated by the points in which the water-courses of
the secondary valleys, on each side of it, intersect each
other on it; and these will be the lowest points at which
lines of communication, through the secondary valleys,
connecting the main water-courses, would cross the dividing
ridge.
If two water-courses flow in the same direction, and
parallel to each other, and then at a certain point assume
divergent directions, it will indicate that this is the lowest
point of the ridge between them.
If two water-courses flow in parallel but opposite direc-
tions, depressions in the ridge between them will be shown
by the meeting of the water-courses of the secondary val-
leys on the ridge; or by an approach towards each other,
at any point, of the two principal water-courses.
Furnished with the data obtained from the maps, the
character of the ground should be carefully studied both
ways by the engineer, first from the point of departure to
•that of arrival, and then returning from the latter to the
former, as without this double traverse natural features of
essential importance might escape the eye.
Surveys.—From the results of the reconnaissance, the
engineer will be able to direct understanding^ the requisite
surveys, which consist in measuring the lengths, deter-
mining the directions, and ascertaining both the longitudinal
and cross levels of the different routes, or, as they are
termed, trial lines, with sufficient accuracy to enable him
to make a comparative estimate both of their practicability
and cost. As the expense of making the requisite surveys
is usually but a small item compared with that of con-
structing the communication, no labour should be spared
in running every practicable line, as otherwise naturalESSAY OK BOAD-MAKIKG.
133
features might be overlooked which might have an import*
ant influence on the cost of construction.
Map and Memoir.—The results of the surveys are ac-
curately embodied in a map exhibiting minutely the topo-
graphical features and sections of the different trial lines,
and in a memoir which should contain a particular descrip-
tion of those features of the ground that cannot be shown
on a map, with all such information on other points that
may be regarded as favourable, or otherwise, to the pro-
posed communication; as, for example, the nature of the
soil, that of the water-courses met with, &c., &c.
Location of Common Hoads.—In selecting among the
different trial lines of the survey the one most suitable to
a common road, the engineer is less restricted, from the
nature of the conveyance used, than in any other kind of
communication. The main points to which his attention
should be confined are—1, to connect the points of arrival
and departure by the most direct, or shortest line; 2, to
avoid unnecessary ascents and descents, or, in other words,
to reduce the ascents and descents to the smallest practi-
cable limit; 3, to adopt such suitable slopes, or gradients,
for the aaris, or centre line of the road, as the nature of the
conveyance may demand; 4, to give the axis such a posi-
tion, with regard to the surface of the ground and the
natural obstacles to be overcome, that the cost of con-
struction for the excavations and embankments required by
the gradients, and for the bridges and other accessories,
shall be reduced to the lowest amount.
Deviations from the right line drawn on the map, be-
tween the points of arrival and departure, will be often
demanded by the natural features of the ground. In
passing the dividing ridges of main, or secondary valleys,
for example, it will frequently be found more advantageous,
both for the most suitable gradients, and to diminish the
amount of excavation and embankment, to cross the ridge
at a lower point than the one in which it is intersected by
the right lme, deviating from the right line either towards
the head, or upper part of the valley, or towards its outlet,
according to the advantages presented by the natural
features of the ground, both for reducing the gradients and
the amount of excavation and embankment.
Where the right line intersects either a marsh or water-
course, it may be found less expensive to change the direc-134	peoeessob mahjln’s elementaey
tion, avoiding the marsh, or intersecting the water-course
at a point where the cost of construction of a bridge, or of
the approaches to it, will be more favourable than the one
in which it is intersected by the right line.
Changes from the direction of the right line may also
be favourable for the purpose of avoiding the intersection
of secondary water-courses; of gaining a better soil for the
roadway ; of giving a better exposure of its surface to the
sun and wind; or of procuring better materials for the
road-covering.
By a careful comparison of the advantages presented by
these different features, the engineer will be enabled to
decide how far the general direction of the right line may
be departed from with advantage to the location. By
choosing a more sinuous course the length of the line will
often not be increased to any very considerable degree,
while the cost of construction may be greatly reduced,
either in obtaining more favourable gradients, or in lessen-
ing the amount of excavation and embankment.
When the points of arrival and departure are upon
different levels, as is usually the case, it will seldom be
practicable to connect them by a continual ascent. The
most that can be done will be to cross the dividing ridges
at their lowest points, and to avoid, as far as practicable,
the intersection of considerable secondary valleys which
might require any considerable ascent on one side and
descent on the other.
The gradients upon common roads will depend upon the
kind of material used for the road-covering, and upon the
state in which the road-surface is kept. The gradient in
all cases should be less than the angle of repose, or of that
inclination of the axis of the road in which the ordinary
vehicles for transportation would remain at a state of rest,
or, if placed in motion, would descend by the action of
gravity with uniform velocity.
The gradients corresponding to the angle of repose have
been ascertained by experiments made upon the various
road-coverings in ordinary use, by allowing a vehicle to
descend along a road of variable inclination until it was
brought to a state of rest by the retarding force of fric-
tion ; also, by ascertaining the amount of force, termed the
force of traction, requisite to put in motion a vehicle with a
given load on a level road.ESSAV ON EO AD-MAKING.
135
The following are the results of experiments made by
Sir John Macneill, to determine the force of traction for
one ton upon level roads.
No. 1. Good pavement, the force of traction is 331bs.
„ 2. Broken stone surface laid on an old
flint road..........................65	„
„	3.	Gravel road.........................147	„
„ 4. Broken stone surface on a rough pave-
ment bottom................................46	„
„	5.	Broken stone	surface on a bottom of
beton...............................46	„
From this it appears that the angle of repose in the first
case is represented by o? or -bV nearly; and that the
slope of the road should therefore not be greater than one
perpendicular to sixty-eight in length; or that the height
to be overcome must not be greater than one sixty-eighth
of the distance between the two points measured along the
road, in order that the force of friction may counteract that
of gravity in the direction of the road.
A similar calculation will show that the angle of repose
in the other cases will be as follows :—
No. 2, .	.	.	. 1 to .	.	.35 nearly.
,, 3, .	.	.	.1 to ... 15	„
„ 4 and 5,	.	. 1 to .	.	. 49	„
These numbers, which give the angle of repose between
*5^- and -fg for the kinds of road-covering Nos. 2 and 4 in
most ordinary use, and corresponding to a road-surface in
good order, may be somewhat increased, to from to
for the ordinary state of the surface of a well-kept road,
without there being any necessity for applying a brake to
the wheels in descending, or going out of a trot in ascend-
ing. The steepest gradient that can be allowed on roads
with a broken-stone covering is about as this, from
experience, is found to be about the angle of repose upon
roads of this character in the state in which they are
usually kept. Upon a road with this inclination, a horse
can draw at a walk his usual load for a level without re-
quiring the assistance of an extra horse; and experience
has further shown that a horse at the usual walking pace will
attain, with less apparent fatigue, the summit of a gra-
dient of ^ in nearly the same time that he would re-136	PE0FESS0B mahan’s elementaby
quire to reach the same point on a trot over a gradient
ST*
A road on a dead level, or one with a continued and
uniform ascent between the points of arrival and depar-
ture, where they lie upon different levels, is not the most
favourable to the draft of the horse. Each of these seems
to fatigue him more than a line of alternate ascents and
descents of slight gradients; as, for example, gradients
of yfq-, upon which a horse will draw as heavy a load with
the same speed as upon a horizontal road.
The gradients should in all cases be reduced as far as
practicable, as the extra exertion that a horse must put
forth in overcoming heavy gradients is very considerable;
they should, as a general rule, therefore, be kept as low at
least as 3^, wherever the ground will admit of it. This
can generally be effected, even in ascending steep hill-
sides, by giving the axis of the road a zig-zag direction,
connecting the straight portions of the zig-zags by circular
arcs. The gradients of the curved portions of the zig-zags
should be reduced, and the roadway also at these points
be widened, for the safety of vehicles descending rapidly.
The width of the roadway may be increased about one-
fourth, when the angle between the straight portions of
the zig-zags is from 120° to 90°; and the increase should be
nearly one-half where the angle is from 90° to 60°.
Having laid down upon the map the approximate loca-
tion of the axis of the road, a comparison can then be made
between the solid contents of the excavations and embank-
ments, which should be so adjusted that they shall balance
each other, or, in other words, the necessary excavations
shall furnish sufficient earth to form the embankments.
To effect this, it will frequently be necessary to alter the
first location, by shifting the position of the axis to the
right or left of the position first assumed, and also by
changing the gradients within the prescribed limits. This
is a problem of very considerable intricacy, whose solution
can only be arrived at by successive approximations. Eor
this purpose, the line must be subdivided into several
portions, in each of which the equalization should be at-
tempted independently of the rest, instead of trying a
general equalization for the whole line at once.
In the calculations of solid contents required in balanc-
ing the excavations and embankments, the most accurate
method consists in subdividing the different solids intoESSAY OK BOAD-MAKIKG.
137
Others of the most simple geometrical forms, as prisms,
prismoids, wedges, and pyramids, whose solidities are
readily determined by the ordinary rules for the mensura-
tion of solids. As this process, however, is frequently
long and tedious, other methods requiring less time, but
not so accurate, are generally preferred, as their results
give an approximation sufficiently near the true for most
practical purposes. They consist in taking a number of
equidistant profiles, and calculating the solid contents be-
tween each pair, either by multiplying the half sum of
their areas by the distance between them, or else by taking
the profile at the middle point between each pair, and
multiplying its area by the same length as before. The
latter method is the more expeditious; it gives less than
the true solid contents, but a nearer approximation than
the former, which gives more than the true solid contents,
whatever may be the form of the ground between each
pair of cross profiles.
In calculating the solid contents, allowance must be
made for the difference in bulk between the different kinds
of earth when occupying their natural bed and when made
into embankment. From some careful experiments on
this point made by Mr. Elwood Morris, a civil engineer,
and published in the Franklin Journal, it appears that
light sandy earth occupies the same space both in excava-
tion and embankment; clayey earth about one-tenth less
in embankment than in its natural bed; gravelly earth
also about one-twelfth less ; rock in large fragments about
five-twelfths more, and in small fragments about six-tenths
more.
Another problem connected with the one in question,
is that of determining the lead, or the mean distance to
which the earth taken from the excavations must be
carried to form the embankments. From the manner in
which the earth is usually transported from the one to the
other, this distance is usually that between the center of
gravity of the solid of excavation and that of its corre-
sponding embankment. Whatever disposition may be
made of the solids of excavation, it is important, so far as
the cost of their removal is concerned, that the lead should
be the least possible. The solution of the problem under
this point of view will frequently be extremely intricate,
and demand the application of all the resources of the
higher analysis. One general principle, however, is to be138
PROFESSOR MAHAN’S ELEMENTARY
observed in all cases, in order to obtain an approximate
solution, which is, that in the removal of the different
portions of the solid of excavation to their corresponding
positions on that of the embankment, the paths passed
over by their respective centers of gravity shall not cross
each other either in a horizontal or vertical direction.
This may in most cases be effected by intersecting the
solids of excavation and embankment by vertical planes in
the direction of the removal, and by removing the partial
solids between the planes within the boundaries marked
out by them.
The definite location having been settled by again going
over the line, and comparing the features of the ground
with the results furnished by the preceding operations,
general and detailed maps of the different divisions of the
definite location are prepared, which should give, with the
utmost accuracy, the longitudinal and cross sections of the
natural ground, and of the excavations and embankments,
with the horizontal and vertical measurements carefully
written upon them, so that the superintending engineer
may have no difficulty in setting out the work from them
on the ground.
In addition to these maps, which are mainly intended to
guide the engineer in regulating the earth-work, detailed
drawings of the road-covering, of the masonry and car-
pentry of the bridges, culverts, &c., accompanied by written
specifications of the manner in which the various kind of
work is to be performed, should be prepared for the guidance
both of the engineer and workmen.
With the data furnished by the maps and drawings, the
engineer can proceed to set out the line on the ground.
The axis of the road is determined by placing stout stakes,
or pickets, at equal intervals apart, which are numbered to
correspond with the same points on the map. The width
of the roadway and the lines on the ground corresponding
to the side slopes of the excavations and embankments, are
laid out in the same manner, by stakes placed along the
lines of the cross profiles.
Besides the numbers marked on the stakes, to indicate
their position on the map, other numbers, showing the
depth of the excavations, or the height of the embankments
from the surface of the ground, accompanied by the letters
Gutt. Fill, to indicate a cutting, or 2» filling, as the case may
be, are also added to guide the workmen in their opera-ESSAY ON BOAD-MARESO.
139
tions. The positions of the stakes on the ground, which
show the principal points of the axis of the road, should,
moreover, be laid down on the map with great accuracy,
by ascertaining their bearings and distances from any fixed
and marked objects in their vicinity, in order that the
points may be readily found should the stakes be subse-
quently misplaced.
Earth-work.—This term is applied to whatever relates to
the construction of the excavations and embankments, to
prepare them for receiving the road-covering.
In forming the excavations, the inclination of the side
slopes demands peculiar attention. This inclination will
depend on the nature of the soil, and the action of the
atmosphere and internal moisture upon it. In common
soils, as ordinary garden earth formed of a mixture of clay
and sand, compact clay, and compact stony soils, although
the side slopes would withstand very well the effects of the
weather with a greater inclination, it is best to give them
two base to one perpendicular; as the surface of the road-
way will, by this arrangement, be well exposed to the
action of the sun and air, which will cause a rapid evapo-
ration of the moisture on the surface. Pure sand and gravel
may require a greater slope, according to circumstances.
In all cases where the depth of the excavation is great, the
base of the slope should be increased. It is not usual to
use any artificial means to protect the surface of the side
slopes from the action of the weather; but it is a pre-
caution which, in the end, will save much labour and ex-
pense in keeping the roadway in good order. The simplest
means which can be used for this purpose, consists in
covering the slopes with good sods, or else with a layer of
vegetable mould about four inches thick, carefully laid and
sown with grass seed. These means will be amply suffi-
cient to protect the side slopes from injury when they are
not exposed to any other causes of deterioration than the
wash of the rain, and the action of frost on the ordinary
moisture retained by the soil.
The side slopes form usually an unbroken surface from
the foot to the top. But in deep excavations, and par-
ticularly in soils liable to slips, they are sometimes formed
with horizontal offsets, termed benches, which are made a
few feet wide and have a ditch on the inner side to receive
the surface-water from the portion of the side slope above140	PROCESSOR mahan’s elementary
them. These benches catch and retain the earth that may
fall from the portion of the side slope above.
When the side slopes are not protected, it will be well,
in localities where stone is plenty, to raise a small wall of
dry stone at the foot of the slopes, to prevent the wash of
the slopes from being carried into the roadway.
A covering of brush-wood, or a thatch of straw, may
also be used with good effect; but, from their perishable
nature, they will require frequent renewal and repairs.
In excavations through solid rock, which does not dis-
integrate on exposure to the atmosphere, the side slopes
might be made perpendicular; but as this would exclude,
in a great degree, the action of the sun and air, which is
essential to keeping the road-surface dry and in good order,
it will be necessary to make the side Blopes with an incli-
nation, varying from one base to one perpendicular, to one
base to two perpendicular, or even greater, according to
the locality ; the inclination of the slope on the south side
in northern latitudes being greatest, to expose better the
road-surface to the sun’s rays.
The slaty rocks generally decompose rapidly on the
surface, when exposed to moisture and the action of frost.
The side slopes in rocks of this character may be cut into
steps, and then be covered by a layer of vegetable mould
sown in grass seed, or else the earth may be sodded in the
usual way.
The stratified soils and rocks, in which the strata have a
dip, or inclination to the horizon, are liable to slips, or to
give way, by one stratum becoming detached and sliding
on another; which is caused either from the action of
frost, or from the pressure of water, which insinuates itself
between the strata. The worst soils of this character are those
formed of alternate strata of clay and sand; particularly if
the clay is of a nature to become semi-fluid when mixed
with water. The best preventives that can be resorted to
in these cases are, to adopt a thorough system of drainage,
to prevent the surface-water of the ground from running
down the side slopes, and to cut off all springs which run
towards the roadway from the side slopes. The surface-
water may be cut off by means of a single ditch made on
the up-hill side of the road, to catch the water before it
reaches the slope of the excavation, and convey it off to
the natural water-courses most convenient; as, in almostESSAY OK BOAD-MAKING.
141
every case, it will be found that the side slope on the
down-hill side is, comparatively speaking, but slightly
affected by the surface-water.
Where slips occur from the action of springs, it fre-
quently becomes a very difficult task to secure the side
slopes. If the sources can be easily reached by excavating
into the side slopes, drains formed of layers of fascines,
or brush-wood, may be placed to give an outlet to the
water, and prevent its action upon the side slopes. The
fascines maybe covered on top with good sods laid with
the grass side beneath, and the excavation made to place
the drain be filled in with good earth well rammed. Drains
formed of broken stone, covered in like manner on top
with a layer of sod to prevent the drain from becoming
choked with earth, may be used under the same circum-
stances as fascine drains. WTiere the sources are not
isolated, and the whole mass of the soil forming the side
slopes appears saturated, the drainage may be effected by
excavating trenches a few feet wide at intervals to the
depth of some feet into the side slopes, and filling them
with broken stone, or else a general drain of broken stone
may be made throughout the whole extent of the side
slope by excavating into it. When this is deemed neces-
sary, it will be well to arrange the drain like an inclined
retaming-wall, with buttresses at intervals projecting into
the earth further than the general mass of the drain. The
front face of the drain should, in this case, also be covered
with a layer of sods with the grass side beneath, and upon
this a layer of good earth should be compactly laid to
form the face of the side slopes. The drain need only be
carried high enough above the foot of the side slope to tap
all the sources; and it should be sunk sufficiently below the
roadway surface to give it a secure footing.
The drainage has been effected, in some cases, by sink-
ing wells or shafts at some distance behind the side slopes,
from the top surface to the level of the bottom of the
excavation, and leading the water which collects in them
by pipes into drains at the foot of the side slopes. In
others, a narrow trench has been excavated, parallel to the
axis of the road, from the top surface to a sufficient depth
to tap all the sources which flow towards the side slope,
and a drain formed either by filling the trench wholly with
broken stone, or else by arranging an open conduit at the
bottom to receive the water collected, over which a layer142
pboeessob mahan’s elementaby
of brush-wood is laid, the remainder of the trench being
filled with broken stone.
In some recent instances in England, the side slopes of
very bad soils have been secured by a facing of brick
arranged in a manner very similar to the method resorted
to for securing the perpendicular sides of narrow deep
trenches by a timber-facing. The plan pursued is, to place,
at intervals along the excavation, strong buttresses of brick
on each side, opposite to each other, and to connect them
at bottom by a reversed arch. Between these buttresses
are placed, at suitable heights, one or more brick beams,
formed at bottom with a flat segment arch, and at top with
a like inverted arch. The buttresses, secured in this way,
serve as piers for vertical cylindrical arches, which form
the facing and support the pressure of the earth between
the buttresses.
In forming the embankments, the side slopes should be
made with a less inclination than that which the earth
naturally assumes ; for the purpose of giving them greater
durability, and to prevent the width of the top surface,
along which the roadway is made, from diminishing by
every change in the side slopes, as it would were they madfe
with the natural slope. To protect the side slopes more
effectually, they should be sodded, or sown in grass seed;
and the surface-water of the top should not be allowed to
run down them, as it would soon wash them into gullies,
and destroy the embankment. In localities where stone is
plenty, a sustaining wall of dry stone may be advan-
tageously substituted for the side slopes.
To prevent, as far as possible, the settling which takes
place in embankments, they should be formed with great
care; the earth being laid in successive layers of about four
feet in thickness, and each layer well settled with rammers.
As this method is very expensive, it is seldom resorted to
except in works which require great care, and are of trifling
extent. Eor extensive works, the method usually followed,
on account of economy, is to embank out from one end,
carrying forward the work on a level with the top surface.
In this case, as there must be a want of compactness in the
mass, it would be best to form the outsides of the embank-
ment first, and to gradually fill in towards the center, in
order that the earth may arrange itself in layers with a
dip from the sides inwards; this will in a great measure
counteract any tendency to slips outward. The foot of theESSAY ON BO AD-51 AKING.
143
slopes should be secured by buttressing them either by a
low stone wall, or by forming a slight excavation for the
same purpose.
When the axis of the roadway is laid out on the side
slope of a hill, and the road-surface is formed partly by ex-
cavating and partly by embanking out, the usual and most
simple method is to extend out the embankment gradually
along the whole line of excavation. This method is in-
secure, and no pains therefore should be spared to give the
embankment a good footing on the natural surface upon
which it rests, particularly at the foot of the slope. For
this purpose the natural surface should be cut into steps,
or offsets, and the foot of the slope be secured by buttress-
ing it against a low stone wall, or a small terrace of care-
fully rammed earth.
In side-formings along a natural surface of great incli-
nation, the method of construction just explained will not
be sufficiently secure; sustaining^walls must be substi-
tuted for the side slopes, both of the excavations and
embankments. These walls may be made simply of dry
stone, when the stone can be procured in blocks of sufficient
size to render this kind of construction of sufficient sta-
bility to resist the pressure of the earth. But when the
blocks of stone do not offer this security, they must be
laid in mortar, and hydraulic mortar is the only kind which
will form a safe construction. The wall which supplies the
slope of the excavation should be carried up as high as
the natural surface of the ground; the one that sustains
the embankment should be built up to the surface of the
roadway; and a parapet-wall should be raised upon it, to
secure vehicles from accidents in deviating from the line
of the roadway.
A road may be constructed partly in excavation and
partly in embankment along a rocky ledge, by blasting the
rock, when the inclination of the natural surface is not
greater than one perpendicular to two base; but with
a greater inclination than this, the whole should be in
excavation.
There are examples of road constructions, in localities
like the last, supported on a frame-work, consisting of
horizontal pieces, which are firmly fixed at one end by
being let into holes drilled in the rock, and are sustained
at the other by an inclined strut underneath, which rests
against the rock in a shoulder formed to receive it.144
professor mahan’s elementary
When the excavations do not furnish sufficient earth for
the embankments, it is obtained from excavations termed
side-cuttings, made at some place in the vicinity of the em-
bankment, from which the earth can be obtained with the
most economy.
If the excavations furnish more earth than is required
for the embankment, it is deposited in what is termed a
spoil-bank, on the side of the excavation. The spoil-bank
should be made at some distance back from the side slope
of the excavation, and on the down-hill side of the top-
surface; and suitable drains should be arranged to carry
off any water that might collect near it and affect the
side slope of the excavation.
The forms to be given to side-cuttings and spoil-banks
will depend, in a great degree, upon the locality: they
should, as far as practicable, be such that the cost of
removal of the earth shall be least possible.
Drainage.—A system of thorough drainage, by which
the water that filters through the ground will be cut off
from the soil beneath the roadway, to a depth of at least
three feet below the bottom of the road-covering, and by
which that which falls upon the surface will be speedily
conveyed off, before it can filter through the road-covering,
is essential to the good condition of a road.
The surface-water is conveyed off by giving the sur&ce
of the roadway a slight transverse convexity, from the
middle to the sides, where the water is received into the
gutters, or side channels, from which it is conveyed by
underground aqueducts, termed culverts, built of stone or
brick, and usually arched at top, into the main drains that
communicate with the natural water-courses. This con-
vexity is regulated by making the figure of the profile
an ellipse, of which the semi-tranverse axis is 15 feet,
and the semi-conjugate axis 9 inches; thus placing the
middle of the roadway nine inches above the bottom of
the side channels. This convexity, which is as great as
should be given, will not be sufficient in a flat country to
keep the road-surface dry; and in such localities, if a
slight longitudinal slope cannot be given to the road, it
should be raised, when practicable, three or four feet above
the general level; both on account of conveying off speedily
the surface-water, and exposing the surface better to the
action of the wind.
To drain the soil beneath the roadway in a level country, *ESSAY OS EOAD-MAKItfG.
145
ditches, termed open side drains, are made parallel to
the road, and at some feet from it on each side. The
bottom of the side drains should be at least three feet
below the road-covering; their size will depend on the
nature of the soil to be drained. In a cultivated country
the side drains should be on the field side of the fences.
As open drains would be soon filled along the parts of a
road in excavation, by the washings from the side slopes,
covered drains, built either of brick or stone, must be sub-
stituted for them. Such drains consist simply of a floor-
ing of flagging stone, or of brick, with two side walls of
rubble, or brick masonry, which support a top covering of
flat stones, or of brick, with open joints, of about half an
inch, to give a free passage-way to the water into the
drain. The top is covered with a layer of straw or brush-
wood; and clean gravel, or broken stone, in small frag-
ments, is laid over this, for the purpose of allowing the
water to filter freely through to the drain, without carry-
ing with it any earth or sediment, which might in time
accumulate and choke it. The width and height of eo-
vered drains will depend on the materials of which they
are built, and the quantity of water to which they yield a
passage.
Besides the longitudinal covered drains in cuttings,
other drains are made under the roadway, which, from their
form, are termed cross mitre drains. Their plan is in
shape like the letter V, the angular point being at the
centre of the road	the direction of its
ascent. The angle	^ lated that the bottom
of the drain shall not have a greater slope along either of its
branches, than one perpendicular to one hundred base, to
preserve the masonry from damage by the current. The
construction of mitre drains is the same as the covered
longitudinal drains. They should be placed at intervals of
about sixty yards from each other.
In some cases surface drains, termed catch-water drains,
are made on the side slopes of cuttings. They are run
up obliquely along the surface, and empty directly into the
cross drains which convey the water into the natural
water-courses.
When the roadway is in side-forming, cross drains of the
ordinary form of culverts are made, to convey the water
from the side channels and the covered drains into the
natural water-courses. They should be of sufficient di-
G146	pbofessob mahan’s elementaby
mensions to convey off a large volume of water, and to
admit a man to pass through them so that they may
be readily cleared out, or even repaired, without breaking
up the roadway over them.
The only drains required for embankments are the or-
dinary side channels of the roadway, with occasional cul-
verts, to convey the water from them into the natural
water-courses. Great care should be taken to prevent
the surface-water from running down the side slopes, as
they would soon be washed into gullies by it.
Yery wet and marshy soils require to be thoroughly
drained before the roadway can be made with safety. The
best system that can be followed in such cases, is to cut a
wide and deep open main drain on each side of the road,
to convey the water to the natural water-courses. Covered
cross drains should be made at frequent intervals, to drain
the soil under the roadway. They should be sunk as low
as will admit of the water running from them into the
main drains, by giving a slight slope to the bottom each
way from the center of the road to facilitate its flow.
Independently of the drainage for marshy soils, they will
require, when the subsoil is of a spongy elastic nature, an
artificial bed for the road-covering. This bed may, in
some cases, be formed by simply removing the upper
stratum to a depth of several feet, and supplying its place
with well-packed gravel, or any soil of a firm character.
In other cases, when the subsoil yields readily to the
ordinary pressure that the road-surface must bear, a bed
of brushwood, from nine to eighteen inches in thickness,
must be formed to receive the soil on which the road-
covering is to rest. The brushwood should be carefully
selected from the long straight slender shoots of the branches
or undergrowth, and be tied up in bundles, termed fascines,
from nine to twelve inches in diameter, and from ten to
twenty feet long. The fascines are laid in alternate layers
crosswise and lengthwise, and the layers are either con-
nected by pickets, or else the withes, with which the
fascines are bound, are cut to allow the brushwood to form
a uniform and campact bed.
This method of securing a good bed for structures on a
weak wet soil has been long practised in Holland, and
experience has fully tested its excellence,
Road^covermgs. — The object of a road-covering being
to diminish the resistances arising from collision andESSAY ON BOAD-MAKING.
147
friction, and thereby to reduce the force of traction to the
least practicable amount, it should be composed of hard
and durable materials, laid on a firm foundation, and pre-
sent a uniform, even surface.
The material in ordinary use for road-coverings is stone,
either in the shape of blocks of a regular form, or of large
round pebbles, termed a pavement; or broken into small
angular masses; or in the form of gravel.
Pavements.—The pavements in most general use in our
country are constructed of rounded pebbles, known as
pa/vmg~stones, varying from three to eight inches in dia-
meter, which are set in a form, or bed of clean sand or
gravel, a foot or two in thickness, which is laid upon the
natural soil excavated to receive the form. The largest
stones are placed in the center of the roadway. The stones
are carefully set in the form, in close contact with each
other, and are then firmly settled by a heavy rammer until
their tops are even with the general surface of the roadway,
which should be of a slightly convex shape, having a slope
of about from the center each way to the sides. After
the stones are driven, the road-surface is covered with a
layer of clean sand, or fine gravel, two or three inches in
thickness, which is gradually worked in between the stones
by the combined action of the travel over the pavement and
of the weather.
The defects of pebble pavements are obvious, and con-
firmed by experience. The form of sand or gravel, as
usually made, is not sufficiently firm; it should be made
in separate layers of about four inches, each layer being
moistened and well settled either by ramming, or passing
a heavy roller over it. Upon the form prepared in this
way a layer of loose material of two or three inches in
thickness may be placed, to receive the ends of the paving-
stones. From the form of the pebbles, the resistance
to traction arising from collision and friction is very great.
Pavements termed stone tramways have been tried in
some of the cities of Europe, both for light and heavy
traffic. They are formed by laying two lines of long stone
blocks for the wheels to run on, with a pavement of pebble
for the borsertrack between the wheel-tracks. In crowded
thoroughfares tramways offer but few if any advantages, as
it is impracticable to confine the vehicles to them, and
when exposed to heavy traffic they wear into ruts. The
stone blocks should be carefully laid on a very firm bottom-
G 2148
PB0FESS0B MAHALS ELEMEffTABY
ing, and particular attention is requisite to prevent ruts
from forming between the blocks and the pebble pave-
ment.
Stone suitable for pavements should be hard and tough,
and not wear smooth under the action to which it is ex-
posed. Some varieties of granite have been found in Eng-
land to furnish the best paving blocks. In France, a
•very fine-grained compact gray sandstone of a bluish cast
is mostly in use for the same purpose, but it wears quite
smooth.
The sand used for forms should be clean and free from
pebbles and gravel of a larger grain than about two-tenths of
an inch. The form should be made by moistening the sand,
and compressing it in layers of about four inches in thick-
ness, either by ramming, or by passing over each layer
several times a heavy iron roller. Upon the top layer
about an inch of loose sand may be spread to receive the
blocks; the joints between which, after they are placed,
should be carefully filled with sand.
The sand form, when carefully made, presents a very
firm and stable foundation for the pavement.
Wooden pavements, formed of blocks of wood of various
shapes, have been tried in England, and several of the
cities of the United States, within the last few years, but
are now for the most part abandoned, as the material has
been found to decay very rapidly, even when prepared with
some of the preservatives of timber against the rot.
Asphaltic pavements have undergone a like trial, and
have also been found to fail after a few years’ service.
This material is further objectionable as a pavement in
cities, where the pavements and sidewalks have frequently
to be disturbed for the purposes of repairing, or laying
down sewers, water-pipes, and other necessary conve-
niences.
The best system of pavement is that which has been
partially put in practice in some of the commercial cities
of England, the idea of which seems to have been taken
from the excellent military roads of the Homans, vestiges
of which remain at the present day in a good state.
In constructing this pavement, a bed is first prepared,
by removing the surface of the soil to the depth of a foot
or more, to obtain a firm stratum; the surface of this bed
receives a very slight convexity, of about two inches to ten
feet, from the center to the sides of the roadway. If theESSAY ON ROAD-MAKING.
149
soil is of a soft clayey nature, into which small fragments
of broken stone would be easily worked by the wheels of
vehicles, it should be excavated a foot or two deeper to
receive a form of sand, or of clean fine gravel. On the
surface of the bed thus prepared, a layer of small broken
stone, four inches thick, is laid; the dimensions of these
fragments should not be greater than two and a half
inches in any direction; the road is then opened to vehi-
cles until this first layer becomes perfectly compact; care
being taken to fill up any ruts with fresh stone, in order
to obtain an uniform surface. A second layer of stone, of
the same thickness as the first, is then laid on, and treated
in the same manner; and, finally, a third layer. When the
third layer has become perfectly compact, and is of an
uniform surface, a layer of fine clean gravel, two and a
half inches thick, is spread evenly over it to receive the
paving-stones. The blocks of stone are of a square shape,
and of different sizes, according to the nature of the
travelling over the pavement. The largest size are ten
inches thick, nine inches broad, and twelve inches long;
the smallest are six inches thick, five inches broad, and
ten inches long. Each block is carefully settled in the
form, by means of a heavy beetle; it is then removed in
order to cover the side of the one against which it is to
rest with hydraulic mortar; this being done, the block is
replaced, and properly adjusted. The blocks of the dif-
ferent courses across the roadway should break joints.
The surface of the road is convex; the convexity being
determined by making the outer edges six inches lower
than the middle, for a width of thirty feet.
This system of pavement fulfils in the best manner all
the requisites of a good road-covering, presenting a hard
even surface to the action of the wheels, and reposing on a
firm bed formed by the broken-stone bottoming. The
mortar-joints, so long as they remain tight, will effectually
prevent the penetration of water beneath the pavement;
but it is probable, from the effect of the transit of heavily-
laden vehicles, and from the expansion and contraction of
the stone, which in our climate is found to be very con-
siderable, that the mortar would soon be crushea and
washed out.
In France, and in many of the large cities of the Con-
tinent, the pavements are made with blocks of rough stone150	proeessor mahan’s elementary
of a cubical form, measuring between eight and nine inches
along the edge of the cube. These are laid on a form of
sand of only a few inches thick when the soil beneath is
firm; but in bad soils the thickness is increased to from
six to twelve inches. The transversal joints are usually
continuous, and those in the direction of the axis of the
road break joints. In some cases the blocks are so laid
that the joints make an angle of 45° with the axis of the
roadway, one set being continuous, the other breaking
joints with them. By this arrangement of the joints, it is
said that the wear upon the edges of the blocks, by which
the upper surface soon assumes a convex shape, is di-
minished. It has been ascertained by experience, that the
wear upon the edges of the blocks is greatest at the joints
which run transversely to the axis when the blocks are
laid in the usual manner. From the experiments of M.
Morin, to ascertain the influence of the shape of stone
blocks on the force of traction, it was found that the
resistance offered by a pavement of blocks averaging from
five to six inches in breadth, measured in the direction
of the axis of the roadway, and about nine inches in
length, was less than in one of cubical blocks of the
ordinary size.
Pavements in cities must be accompanied by sidewalks,
and crossing-places, for foot-passengers. The sidewalks
are made of large flat flagging-stone, at least two inches
thick, laid on a form of clean gravel well rammed and
settled. The width of the sidewalks will depend on the
street being more or less frequented by a crowd. It
would, in all cases, be well to have them at least twelve
feet wide; they receive a slope, or pitch, of one inch to ten
feet, towards the pavement, to convey the surface-water
to the side channels. The pavement is separated from the
sidewalk by a row of long slabs set on their edges, termed
curbstones, which confine both the flagging and paving-
stones. The curb-stones form the sides of the side chan-
nels, and should for this purpose project six inches above
the outside paving-stones, and be sunk at least four inches
below their top surface; they should, moreover, be flush
with the upper surface of the sidewalks, to allow the water
to run over into the side channels, and to prevent accidents
which might otherwise happen from their tripping persons
passing in haste.ESSAY ON EOAD-MAKING.
151
The crossings should be from four to six feet wide, and
be slightly raised above the general surface of the pave-
ment, to keep them free from mud.
Broken stone road-covering.—The ordinary road-cover-
ing for common roads, in use in this country and Europe,
is formed of a coating of stone broken into small frag-
ments, which is laid either upon the natural soil, or upon
a paved bottoming of small irregular blocks of stone. In
England these two systems have their respective partisans;
the one claiming the superiority for road-coverings of
stone broken into small fragments, a method brought into
vogue some years since by Sir J. McAdam, from whom
these roads have been termed macadamized; the other
being the plan pursued by the late Mr. Telford in the great
national roads constructed in Great Britain within about
the same period.
The subject of road-making has within the last few years
excited renewed interest and discussion among engineers
in Erance; the conclusion* drawn from experience, there
generally adopted is, that a covering alone of stone broken
into small fragments is sufficient under the heaviest traffic
and most frequented roads. Some of the Erench engi-
neers recommend, in very yielding clayey soils, that either
• a paved bottoming after Telford’s method be resorted to,
or that the soil be well compressed at the surface before
placing the road-covering.
The paved bottom road-covering on Telford’s plan is
formed by excavating the surface of the ground to a suit-
able depth, and preparing the form for the pavement with
the precautions as for a common pavement. Blocks of
stone of an irregular pyramidal shape are selected for the
pavement, which, for a roadway thirty feet in width,
should be seven inches thick for the center of the road,
and three inches thick at the sides. The base of each
block should not measure more than five inches, and the
top not less than four inches.
The blocks are set by the hand, with great care, as
closely in contact at their bases as practicable; and blocks
of a suitable size are selected to give the surface of the
pavement a slightly convex shape from the center outwards..
The spaces between the blocks are filled with chippings
of stone compactly set with a small hammer.
A layer of broken stone, four inches thick, is laid over
this pavement, for a width of nine feet on each side of the152	PBOEESSOB MABLOT’s ELEMENTABT
center; no fragment of this layer should measure over two
and a half inches in any direction. A layer of broken stone
of smaller dimensions, or of clean coarse gravel, is spread
over the wings to the same depth as the center layer.
The road-covering, thus prepared, is thrown open to
vehicles until the upper layer has become perfectly com-
pact ; care having been taken to fill in the ruts with fresh
stone, in order to obtain an uniform surface. A second
layer, about two inches in depth, is then laid over the
center of the roadway; and the wings receive also a layer
of new material laid on to a sufficient thickness to make
the outside of the roadway nine inches lower than the
center, by giving a slight convexity to the surface from the
center outwards. A coating of clean coarse gravel, one
inch and a half thick, termed a binding, is spread over the
surface, and the road-covering is then ready to be thrown
open to travelling.
The stone used for the pavement may be of an inferior
quality, in hardness and strength, to that placed at the
surface, as it is but little exposed to the wear and tear
occasioned by travelling. The surface-stone should be of
the hardest kind that can be procured. The gravel bind-
ing is laid over the surface to facilitate the travelling,
whilst the under stratum of stone is still loose; it is, how-
ever, hurtful, as, by working in between the broken stones,
it prevents them from setting as compactly as they would
otherwise do.
If the roadway cannot be paved the entire width, it
should, at least, receive a pavement for the width of nine
feet on each side of the center. The wings, in this case,
may be formed entirely of clean gravel, or of chippings of
stone.
For roads which are not much travelled, like the ordi-
nary cross roads of the country, the pavement will not
demand so much care; but may be made of any stone at
hand, broken into fragments of such dimensions that no
stone shall weigh over four pounds. The surface-coating
may be formed in the manner just described.
In forming a road-covering of broken stone alone, the
bed for the covering is arranged in the same manner as for
the paved bottoming: a layer of the stone, four inches in
thickness, is carefully spread over the bed, and the road
is thrown open to vehicles, care being taken to fill the
ruts, and preserve the surface in a uniform state until theESSAY ON BOAD-MAKING.
153
layer has become compact; successive layers are laid on
and treated in the same maimer as the first, until the
covering has received a thickness of about twelve inches in
the center, with the ordinary convexity at the surface.
Where good gravel can be procured the road-covering
may be made of this material, which should be well
screened, and all pebbles found in it over two and a half
inches in diameter should be broken into fragments of not
greater dimensions than these. A firm level form having
been prepared, a layer of gravel, four inches in thickness,
is laid on, and, when this has become compact from the
travel, successive layers of about three inches in thickness
are laid on and treated like the first, until the covering has
received a thickness of sixteen inches in the center and the
ordinary convexity.
As has been already stated, the French civil engineers
do not regard a paved bottoming as essentials for broken
stone road-coverings, except in cases of a very heavy traffic,
or where the substratum of the road is of a very yielding
character. They also give less thickness to the road-
covering than the Telford’s school deem necessary; allow-
ing not more than six to eight inches to road-coverings
for light traffic, and about ten inches only for the heaviest
traffic.
If the soil upon which the road-covering is to be placed
is not dry and firm, they compress it by rolling, which is
done by passing over it several times an iron cylinder,
about six feet in diameter, and four feet in length, the
weight of which can be increased, by additional weights,
from six thousand to about twenty thousand pounds.
The road material is placed upon the bed, when well com-
pressed and levelled, in layers of about four inches, each
layer being compressed by passing the cylinder several
times over it before a new one is laid on. If the operation
of rolling’is performed in dry weather, the layer of stone
is watered, and some add a thin layer of clean sand, from
four to eight-tenths of an inch in thickness, over each
layer before it is rolled, for the purpose of consolidating
the surface of the layer, by filling the voids between the
broken stone fragments. After the surface has been well
consolidated by rolling, the road is thrown open for travel,
and all ruts and other displacement of the stone on the
surface are carefully repaired, by adding fresh material,
and levelling the ridges by ramming.154
PR0EESS0R MAHAN’S ELEMENTARY
Great importance is attached by the French engineers
to the use of the iron cylinder for compressing the ma-
terials of a new road, and to minute attention to daily
repairs. It is stated that by the use of the cylinder the
road is presented at once in a good travelling condition;
the wear of the materials is less than by the old method of
gradually consolidating them by the travel; the cost of
repairs during the first years is diminished; it gives to
the road-covering a more uniform thickness, and admits of
its being thinner than in the usual method.
Materials and Repairs.—The materials for broken stone
roads should be hard and durable. For the bottom layer
a soft stone, or a mixture of hard and soft, may be used,
but on the surface none but the hardest stone will with-
stand the action of the wheels. The stone should be care-
fully broken into fragments of nearly as cubical a form as
Eracticable, and be cleansed from dirt and of all very small
'agments. The broken stone should be kept in depdts at
convenient points along the line of the road, for repairs.
Too great attention cannot be bestowed upon keeping
the road-surface free from an accumulation of mud and
even of dust. It should be constantly cleaned by scraping
and sweeping. The repairs should be daily made by add-
ing fresh material upon all points where hollows or ruts
commence to form. It is recommended by some that
when fresh material is added, the surface on which it is
spread should be broken with a pick to the depth of half
an inch to an inch, and the fresh material be well settled
by ramming, a small quantity of clean sand being added to
make the stone pack better. When not daily repaired by
persons whose sole business it is to keep the road in good
order, general repairs should be made in the months of
October and April* by removing all accumulations of mud,
cleaning out the side channels and other drains, and adding
fresh material where requisite.
The importance of keeping the road-surface at all times
free from an accumulation of mud and dust, and of pre-
serving the surface in a uniform state of evenness, by the
daily addition of fresh material wherever the wear is suffi-
cient to call for it, cannot be too strongly insisted upon.
Without this constant supervision, the best-constructed
road will, in a short time, be unfit for travel, and with
it the weakest may at all times be kept in a tolerably fair
state.ESSAY ON BOAD-MAKING.
155
Cross dimensions of Hoads.—A road thirty feet in width
is amply sufficient for the carriage-way of the most fre-
quented thoroughfares between cities. A width of forty,
or even sixty feet, may be given near cities, where the
greater part of the transportation is effected by land. For
cross roads, and others of minor importance, the width may
be reduced according to the nature of the Gase. The width
should be at least sufficient to allow two of the ordinary
carriages of the country to pass each other with safety. In
all'cases, it should be borne in mind that any unnecessary
width increases both the first cost of construction and the
expense of annual repairs.
very wide roads have in some cases been used, the
center part only receiving a road-covering, and the wings,
termed simmer roads, being formed on the natural surface
of the subsoil. The object of this system is to relieve the
road-covering from the wear and tear occasioned by the
lighter kind of vehicles during the summer, as the wings
present a more pleasant surface for travelling in that
season. But little is gained by this system under this
point of view; and it has the inconvenience of forming
during the winter a large quantity of mud, which is very
injurious to the road-covering.
There should be at least one footpath, from five to six
feet wide, and not more than nine inches higher than the
bottom of the side channels* The surface of the foot-
path should have a pitch of two inches, towards the side
channels, to convey its surface-water into them. When
the natural soil is firm and sandy, or gravelly, its surface
will serve for the footpath; but in other cases the natural
soil must be thrown out to a depth of six inches, and the
excavation filled with fine clean gravel.
To prevent the footpath from being damaged by the
current of water in the side channels, its side slope, next
to the side channel, must be protected by a facing of good
sods, or of dry stone*
As it is of the first importance, in keeping the roadway
in a good travelling state, that its surface should be kept
dry, it will be necessary to remove from it, as far as
practicable, all objects that might obstruct the action
of the wind and the sun on its surface. Bences and
hedges along the road should not be higher than five
feet; and no trees should be suffered to stand on the road-
side of the side drains, for, independently of shading the156
PBOBESSOB MAHAN ON
roadway, their roots would in time throw up the road-
eoyering.
Plank jRoads.—A road-covering, consisting of thick
boards, or planks, resting on longitudinal beams, or sleepers,
and known as plank roads, has, within the past few years,
been.introduced among us ; and from its adaptation to our
uncleared forest districts, its superior economy to the
ordinary road-coverings in such localities, and its intrinsic
merits, as fulfilling the requisites of a good road-covering,
is rapidly coming into extensive use throughout all parts
of the United States.
The method most generally adopted in constructing
plank roads consists in laying a flooring, or track, eight
feet wide, composed of boards from nine to twelve inches
in width, and three inches in thickness, which rest upon
two parallel rows of sleepers, or sills, laid lengthwise of
the road, and having their center lines about four feet
apart, or two feet from the axis of the road. Sills of vari-
ous-sized scantling have been used, but experience seems
in favour of scantling about twelve inches in width, four
inches in thickness, and in lengths of not less than fifteen
to twenty feet. Sills of these dimensions, laid flatwise,
and firmly imbedded, present a firm and uniform bearing
to the boards, and distribute the pressure they receive
over so great a surface, that, if the soil upon which they
rest is compact and kept well drained, there can be but
little settling and displacement of the road-surface, from
the usual loads passing over it. The better to secure this
uniform distribution of the pressure, the sills of one row
are so laid as to break joints with the other; and to pre-
vent the ends of the sills from yielding, the usual pre-
caution is taken to place short sills at the joints, either be-
neath the main sills, or on the same level with them.
The boards are laid perpendicular to the axis of the
road, experience having shown that this position is as
favourable to their wear and tear as any other, and is
otherwise the most economical. Their ends are not in an
unbroken line, but so arranged that the ends of every
three or four project alternately, on each side of the axis
of the road, three or four inches beyond those next to
them, for the purpose of presenting a short shoulder to the
wheels of vehicles, to facilitate their coming upon the
plank surface, when from any cause they may have turned
aside. On some roads the boards have been spiked to thePLANK BO AD 8.
157
sills; but this is, at present, regarded as unnecessary, the
stability of the boards being best secured by well packing
the earth between and around the sills, so as to present,
with them, a uniform bearing surface to the boards, and by
adopting the usual precautions for keeping the subsoil
well drained, and preventing any accumulation of rain-
water on the surface.
The boards for plank roads should be selected from
timber free from the usual defects, such as knots, shakes,
<fcc., which would render it unsuitable for ordinary building
purposes; as durability is an essential element in the
economy of this class of structures. So far as experience
has furnished data, boards of three inches in thickness offer
all the requisites of strength and durability that can be
obtained from timber in its ordinary state, in which it is
used for plank roads.
Besides the wooden track of eight feet, an earthen track
of twelve feet in width is made, which serves as a summer
road for light vehicles, and as a turn-out for loaded ones;
this, with the wooden track, gives a clear road-surface of
twenty feet, the least that can be well allowed for a fre-
quented road. It is recommended to lay the wooden track
on the right hand side of the approach of a road to a town,
or village, for the proper convenience of the rural traffic,
as the heavy trade is to the town. The surface of this
track receives a cross slope from the side towards the
axis of the road outwards of 1 in 32. The surface of
the summer road receives a cross slope in the opposite
direction of 1 in 16. These slopes are given for the pur-
pose of facilitating a rapid sunace drainage. The side
drains are placed for this purpose parallel to the axis
of the road, and connected with the road-surface in a suit-
able slope.
Where, from the character of the soil, good summer
roads cannot be had, it will be necessary to make wooden
turn-outs, from space to space, to prevent the incon-
venience and delay of miry roads. This it is proposed to
do by laying, at these points, a wooden track of double
width, to enable vehicles meeting to pass each other. It
is recommended to lay these turn-outs on four or five sills,
to spring the boards slightly at the center, and spike their
ends to the exterior sills.
The angle of repose, by which the grade of plank roads
should be regulated, has not yet been determined by ex-158
PROFESSOR MAHAN ON PLANK ROADS.
periment; but as the wooden surface is covered with a
layer of clean sand, fine gravel, or tan bark, before it is
thrown open to vehicles, and as it in time becomes covered
with a permanent stratum of dust, &c., it is probable that
this angle will not materially differ from that on a road
with a broken stone surface, like the one of McAdam, or
of Telford, when kept in a thorough state of repair.
In some of the earlier plank roads made in Canada, a
width of sixteen feet was given to the wooden track, the
boards of which were laid upon four or five rows of sills;
experience soon demonstrated that this was by no means
an economical plan, as it was found that vehicles kept the
center of the wooden surface, which was soon worn into a
beaten track, whilst the remainder was but slightly im-
paired. This led to the abandonment of the wide track for
the one now usually adopted, which answers all the ends
of the wants of travel, and is much more economical, both
in the first outlay and for subsequent renewals.
The great advantages of plank roads over every other
kind, in a densely-wooded country, for the rural traffic, are
so obvious, that, did not experience teach us by what mere
accidents, apparently, improvements of the most important
kind have been suggested and carried into effect, it might
be a subject of astonishment that they had not been
among the first to be introduced, after a trial of the old
corduroy roads, so generally resorted to in the early stages
of road-making in the United States.REMARKS
ON THE
MAINTENANCE OF MACADAMISED ROADS.
Bt
GEN. SIB JOHN F. BUBGOYNE, BABT.,
<tc., &c., <tc.The following Remarks were written by Gen.
Sib John E. Buegoyne several years ago, when in
command in Ireland. Road Engineers have pro-
nounced the subject to be so ably and practically
written, that I was induced, by their solicitation, to
ask the Author’s permission to reprint, verbatim, the
whole of the Remarks,—which he has very liberally
and kindly sanctioned.
J. W.REMARKS
ON THE
MAINTENANCE OF MACADAMISED ROADS.
BY
GEN. SIB, JOHN F. BUBGOYNE, BART.,
<fcc.j &o«
Ik France, the construction and maintenance of the great
roads throughout the kingdom are under charge of a Public
Department, the Fonts et Chaussees, which consequently
has an opportunity of generalising any improvement that
may be made in the system.
Till of late years, the practices with regard to the roads
made of broken stone, appear to have been very injudicious,
and far behind those adopted in England. Since then, how-
ever, the Engineers have made great improvements; and
latterly ^ principles of maintenance have been introduced,
that have tended to put them in a very superior state, and
at the same time, to reduce the expenditure.
One of the most recent and most perfect has been carried
into very successful effect by Mons. Dumas, in the district
of the Departement de la Sarthe.
The chief features of this system are—
1st,—The keeping the road perfectly clear of dust,
dirt, or of any unconnected matter over the crust of
consolidated broken stone.
2nd,—Minute repairs to the surface, in small patches,
immediately on the appearance of any want of form or
substance.
The novelty in Mons. Dumas’ mode is not in the opera-
tions themselves, hut in the extent to which he carries them,
as subsequently explained.162	REMARKS ON THE MAINTENANCE
Previous to entering into the question of maintaining a
road, we ought to suppose it to be, in the first instance, in a
proper state.
There are two very important requisites for a road, with-
out which it ought not to be considered, if a new road, as
completed, or if an old one, as efficient, one of which is
generally much neglected, and the other entirely. The one
is thorough drainage; the other, the consolidation, as part
of the work, of any great mass of new laid stone.
It is very rare, indeed, that a road is thoroughly drained.
If it has a longitudiual drain on each side, in which the
water does not remain at any time standing so high as the
lowest part of the cross section of the road, it is considered
to be adequately drained; but it is suggested that under
many circumstances it may fail to be so, and that instances
may be constantly seen where such drainage is quite insuffi-
cient, as in the following cases—
1.	"Where along flat ground, the water remains in the
drain for lengthened periods, up to within a few inches
of the level of the road; the moisture will soak through,
be retained under the surface of the road, and cause it
to be soft and heavy.
2.	Where the road is wide between these drains,
viz.: from 30 to 60 feet, or upwards, and the soil at all
retentive of moisture, the wet will be long in passing
off.
In the drainage of lands for agricultural purposes,
on the system practised by Mr* Smith, of Deanston,
which is generally received as judicious, 18 feet is an
usual distance between his covered drains, while 30 and
40 are extreme distances; and certainly, it is far more
important to underdrain a road.
3.	If there are springs, or any degree of filtration of
water not cut off by the side drains, in the bed of the
road, theory says, and even specifications require, that
they should be drained off, but how seldom in practice
is it attended to P
4.	The flatness that is now given to all roads is such
as will not admit the water to run off them, unless it
falls in very large quantities, and then only partially, or
unless the road be very smooth, hard, and perfect in
shape. Even the slight curve that is required, is very
seldom preserved in the habitual maintenance of theOP MACADAMISED BOADS.	163
road, certainly not in the firm part of it, if any can be
called so.
If a road is to be kept in the ordinary inefficient
condition, it would be decidedly better to give a greater
curvature to its cross section than usual, notwith-
standing the evils attending it.
5.	All the water that falls on the sheets of loose
broken stone, which always lie a considerable time
before they are consolidated, disappears, it is true, from
the surface, but soaks on to the understratum, and is
by so much the worse, as it is in some degree retained
by the consistency of the hollow in the remaining
crust of the road.
6.	It is rare that water has so free a passage as it
ought from the water tables, through the footpaths or
other obstructions.
7.	Lastly, it is not uncommon for the gullets for
passing small water courses under the road, to be quite
insufficient in number or dimensions.
These defects are almost universal; to remedy them
thoroughly, that is, to a degree far greater than is now
usually thought to be at all necessary, would cost much less
than the wear and tear occasioned by their existence, and
indeed without their being thoroughly provided against, no
labour or expense will keep the road in a first rate degree
of perfection.
It is this, perhaps, more than any other circumstance,
that renders it most difficult, by any expenditure, to keep
a Macadamised roadway in the greatly frequented streets
of large towns in any sound state, during a continuance of
very wet weather.
With regard to the second requisite, namely, the consoli-
dation of the broken stone on new roads, (or in cases of
extensive repairs,) before they are given up for the general
traffic, no road ought to be considered to be finished until
thoroughly rolled, that is, to a degree that will admit of
horses in draught trotting over it without much extra
exertion.
As this is seldom, if ever attended to, the propriety of its
adoption requires some distinct explanation and arguments,
for which I would refer to page 184.
The great advantage of maintaining roads in good con-
dition, as a measure of economy, has frequently been164
REMARKS ON THE MAINTENANCE
adverted to, but cannot be too often repeated or too strongly
enforced, particularly since it is little attended to in
practice.
Without going into the question minutely, perhaps the
following, as a single illustration, will not be considered
overstrained:—
Suppose the work of every horse on any given road be
calculated at twenty miles daily journey upon it, and that
the services required be regulated by the number of horses
applied; it is probable that the difference in the state of a
road that would enable four horses instead of five to do any
given amount of work would not be so great as most persons
might imagine.
The calculation may be made in various different ways,
distances traversed, or loads conveyed, or rates of speed may
be varied according to the goodness or defects of the road;
the supposed result, however, by any mode of reasoning, is,
that four-fifths the amount of animal labour should be able
to do the work in one case, that would require one-fifth
more in the other.
Supposing the number of horses employed to be equal to
an average of eighty daily, over twenty miles of the inferior
road,* then sixteen horses (or one-fifth) might be spared if
the road were improved to the condition contemplated on
the above calculation.
Suppose also the value of each horse to be estimated at
£45 per annum, for his purchase, feeding, care, harness,&c.,t
there would be an available amount of £680 per annum for
the improvement and maintenance of this twenty miles of
road at its superior state, or £34 per mile.
If it could be shown that an increased expenditure on the
road, not exceeding that amount, would have the effect of
placing and maintaining it in the superior condition, it must
decidedly be true policy that it should be incurred, not only
on account of the one ingredient of reduction of animal
labour, but on many others on which it is not easy to put a
money value;—such as wear and tear of carriages and
* Equivalent to the work of a single horse over 1600 miles, including
the amount traversed by every horse over every part of this twenty miles.
+ It is submitted, that £45 per annum can hardly be deemed high; it
would probably amount to that average by the addition of a horse to every
carriage ; but when it is considered that most of them are single horse
vehicles, each additional horse in those cases would require an additional
carriage and driver.OP MACADAMISED ROADS.
165
harness; greater degree of lightness and ease that may be
given to the carriages; saving of time by increased degrees
of speed that would be adopted for traffic of all kinds, but
particularly for passengers; greater freedom from mud or
aust; reduction of cruelty to animals, which by no process
can be so great on a good as on a bad road; improved
business in the district, and increased traffic that would be
brought on the road by the additional facility and comfort
it afforded, with very many others.
This argument has reference to the question as regards
the public generally, without consideration of what parties
are to pay for the expenditure, or what parties are to receive
the benefit—a consideration that unfortunately frequently
leads to many impolitic proceedings.
In Ireland, for instance, where the roads are maintained
by county assessment, the amount of funds granted has
chiefly reference to the weight of the tax, and not to the
necessity of the case, or the indirect advantages to the
community from good roads.
The first principle to be established should be the most
beneficial and economical system for the country generally,
and afterwards to regulate the just apportionment and the
manner by which the necessary funds are to be raised.
It is not the object of this paper to go into the question
of how that is to be done—but it may be stated en passant
that Idle turnpike system, on the fallacious reason of those
who use the road paying for it, is considered to be by no
means judicious or equitable.
In treating of the condition of a road, the present inten-
tion is merely to consider how to preserve its surface, with-
out reference to any question of how it may have been
carried through the country, or of its hills, &c., matters that
have more relation to construction than to maintenance.
A road in superior condition is assumed to be one that
has always a hard and even surface, with curvature just
sufficient for the water to run off, without even small
hollows in which it will lodge, without mud in wet weather,
or dust in dry, and at no time with extensive patches of the
usual sized broken stone new laid upon it.
The inferior road is precisely the reverse of this in its
qualities, but the degree of inferiority cannot be very
accurately defined; it may, for the purpose of this argu-
ment, be considered such as would, generally speaking, be
termed a heavy or rough road.166
REMARKS ON THE MAINTENANCE
The time when the relative condition of roads is most
clearly to be perceived is in very wet weather; the good
will then be still quite hard, with no inequalities, no dirt,
no puddles; it will be as a good road in summer recently
watered.
The inferior will be muddy, in numerous puddles, rough,
or soft and heavy.
It has been endeavoured to be shown, that it would be
good policy and economical to expend a considerable addi-
tional sum, annually, in improving and maintaining the road
in the superior manner, if not to be effected without such
extra expenditure.
A road must have at least three or four inches of stoning
upon it, or, if not very firm, wheels will, in parts, cut down
to the sub-soil, and it will be impassable.
As the stone, therefore, is worn down to dust or mud, it
must be renewed in at least equal quantities.
This is all, therefore, that is absolutely necessary to
enable carriages to make use of it; and by an erroneous
inference, which it would appear, judging by the ordinary
course of proceeding, is general, it is considered that the
cheapest mode of maintaining a road in a condition to be
merely passable, is to do no more than lay down stone along
it, just before it arrives at its minimum thickness.
It seems also to be considered, that whatever improve-
ment is made beyond that state, in the goodness of the
road, as a measure of convenience, or for the economy of
the working power on it, must be at the sacrifice of some
direct increase of expense upon the road.
There is, however, great reason to believe that by a proper
system the greatest improvements might be made at very
little, if any, increased outlay.
It would be manifestly a subject of great importance to
prove and establish such a position.
On a thoroughly good road, the wear is even, gradual,
and very slow; the carriages work indiscriminately over
every part; but such a condition must be narrowly watched,
for if left to itself, slight inequalities are formed, each of
which tends to a more rapid wear of the road, and in pro-
portion to the length of time that these are allowed to
continue and increase, and the less frequent and more
extensive are the repairs, by so much will be the injury
done by each carriage: thus, in the first case, where the
traffic of one week may do, in a given distance, ten shillings’OP MACADAMISED ROADS.
167
worth of injury, in the worst of the latter it may do damage
to the value of twelve or fifteen; if, therefore, it can be
maintained at once in the better condition at the higher
rate, though the ultimate expense is the same, yet you have
the good road instead of the bad.
/ Independent of the constant perfect efficiency of the
drainage, and that a good form of cross section be preserved
at every application on the surface, there are two leading
operations to be regulated, namely, the removal of the
produce of the wear, in the shape of dust or mud, and the
application of fresh material to replace the loss.
First, with regard to the dust or mud, arising from wear
or other causes. In roads that are much neglected, this
waste matter is never removed; in such cases, unless under
very favourable circumstances of original good construction,
very perfect drainage, great exposure to the sun and wind,
and small traffic on it, the road will be very dusty in dry,
and very muddy in wet weather, all which not only tend to
make it heavy to the draught, and to create inequalities,
but to increase greatly the grinding operation of the
wheels, and consequently more rapidly to consume the
material.
From such a state of absolute neglect, various gradations
may be adopted ; first, to a partial removal, at long intervals
of time, when there shall be a great accumulation; thence
to a more frequent removal, up to the best system, namely,
that of constant attention, and an entire prevention of any
perceptible collection. In the first case, scrapers of different
materials and forms are used, or shovels and birch brooms,
till, in the latter, the broom alone may be sufficient.
The waste matter from the wear of the road (always
injurious if left upon it) may be removed as dust or as
mud;—in the former state, however, with much greater
facility and advantage. As dust, it is removed before it has
done much injury; it is lighter and easier to collect; a
broom, which is the implement to be used, does not
derange the surface, as a scraper may in the removal of
mud;—the scraping away of mud will leave much that will
form dust; while sweeping away the dust will leave nothing
for mud.
Unfortunately, however, the climate of England and
Ireland, by the proportion of wet as compared with dry
weather, would not admit of this removal of dust to any
very great extent; still the principle should be adhered to168
REMARKS ON THE MAINTENANCE
as much as possible, and at all events no accumulation of
either dust or mud should be allowed.
The constant sweeping away of the dust or soft mud may
be deemed the prevention of evil; the occasional scraping
away the stiff mud in quantities the remedy for it.
The manner of supplying the material for preserving the
necessary thickness for the crust of a road will also admit
of great variation from the worst system, which is that of
waiting till the surface has lost its shape, is covered with
mud and pools of water, to which a thick covering of stone,
broken to the usual dimensions, is applied over extensive
distances, and there left to be worn down by the carriages
that casually pass it.
This necessarily produces very heavy draught—chance of
injury to horses’ feet, a very slow formation and consolida-
tion, a great deal of displacement of material, and extra
grinding and wear and tear; and thus the road is periodically
rendered almost unfit for transit, and ultimately remains a
mis-shapen fixing of not half the quantity laid down.
On that system improvements are introduced by more
frequent patching in smaller quantities at a time, up to that
which may be deemed the most perfect, namely, a constant
watching, and the application of very small patches of stone
broken fine, carefully supplied to the small hollows, as they
shall successively be formed, and to places where the shape
or strength shall be deficient, these parts being loosened
with a pick, and the fresh material rammed down f into
them, and attended to carefully till finally consolidated.
It is very evident that instead of ali the grinding find
crushing of the material which attends the passage of
wheels over the soft rough road, the friction and consequent
wear on that which is perfectly even and hard must be most
trifling„
Under the system here recommended as the best, there
will be no doubt some additional manual labour requisite
on the road, but at the same time a most decided saving of
material and in the carriage of it; and in cases of tolerably
frequented roads, or where material is distant, perhaps it
may be said generally, the saving on that item will be
* Loosening the surface with a pick whenever new material is laid on, is
quite necessary when a road is firm ; those who argne that it is unneces-
sary or wrong, must refer to roads that are soft, in which case it will be
more readily pressed into it, and then also the stone may be broken
larger.OF MACADAMISED ROADS.
169
greater than the extra expenditure on the other; thus
obtaining an absolute reduction of outlay to procure the
perfect road, and what is of advantage in almost every
country where it can be effected without extra expense,
increased work for the labouring population of the vicinity;
that is, the substitution of manual labour for the employ-
ment of material and animals.* It may almost be asserted,
that, under a thorough good system, the better the road is,
the less will be the outlay upon it.
Many of the above remarks have been suggested by
some very interesting papers written by Mons. L. Dumas
and other Drench engineers of the Corps des Fonts et
Chaussees.
They state many facts which establish in a great degree
the gradual improvement of system and the soundness of
these principles.
The following took place with respect to the high roads
(Routes Roy ales') of the Departement de la Sarthe, somewhat
less than 250 miles in extent:—
Per mile.
In 1793 a demand was made to put
them in complete order .	. £15,280 or £60
In 1824 the demand was about	.	9,000 „	36
In 1836	„	„	7,760 „	31
In 1839	„	„ ,	. .	6,640 „	26
And the roads have become better concurrently with the
reduction of cost in maintenance, from being in 1793 in deep
ruts, to 1839, when they were in very good order.
Part of the great road between Lyons and Toulouse till
1833 was always in a dreadful state, and yet cost habitually
about £110 per annum per English mile for maintenance,
when M. Berthault Ducreux introduced a system of patch-
ing instead of general repairs; since when, the road was
gradually improved, till it was in a very good state, and the
annual expense reduced by £13 or £14 per mile.
Another instance is quoted where prior to 1837 the
average amount of broken stone laid on 33 miles of road
was 6,000 cubic yards; under the improved system in 1837
* It is not meant to convey the idea, that the procuring of material and
even the carting is not attended also by a great proportion of manual
labour, but to a smaller amount in equal expenditures^ and much of it to
a different and superior class.170
REMARKS ON THE MAINTENANCE
5000 cubic yards were applied; in 1838 only 1,350 cubic
yards; and in 1839 none.
This last case, however, may have been one of those
where they have found in France the system of heaping
masses of broken stone as the only remedy for a degraded
state of road, which leads to a great superfluous accumula-
tion of material, in many instances amounting to twelve and
fifteen inches, and in some actually to three and even four
feet; in such cases they have subsequently gone on for
years attending to drainage, form, and keeping the road
clean, and applying very little or no fresh material for the
whole time.
In another instance the cost has been as follows:—
Years.	Expenditure.		Total.
	Material.	Road Labour.	
	£	£	£
1830	548	166	714
1831	563	188	751
1832	496	151	647
1833	500	167	667
1834	438	177	615
1835	398	145	543
1836	380	160	540
1837	360	178	538
1838	180	233	413
1839 1		250	300	550
In 1837, when it was taken up on the new system, the
road required considerable improvements: in 1840, two-
thirds of it were in perfect condition; and when the whole
is reformed, it is calculated that from £400 to £440 will
keep it perfect.
Eut more complete illustrations are to be found in the
road from Tours to Caen, in La Sarthe, which was in 1836
in so bad a state that an official report of 3rd May of that
year announced that without a special credit of £2,000
towards it, and a great additional provision of material, there
was danger that it would become impassable; in January,
1837, it was put under the charge of Monsieur Dumas.
The expenditure upon it for some years before and after
that period was as follows:—OF MACADAMISED ROADS*
171
Year.	Material	Road Labour.	Total.
£	£	£	£
1832	872	195	1,067
1833	708	205	913
1834	745	236	981
1835	671	280	951
1836	684	293	977
1837	584	504	1,088
1838	445	456	901
1839	412	420	832
1840	271	392	663
1841	163	445	608*
In August, 1838, this road was reported to be in a very-
good state, and since then it has become better and
better.
In 1834, the mail required always five horses, and the
road was then so bad that the postmaster lost eleven by the
hard work in one year. In 1837 it required four and five
horses. In 1838 the number of horses was reduced to
three ; and at present there are only two of middling
quality, and the postmaster loses none from that cause.
In this same district, in consequence of the improvement
of these roads, since 1839, a number of lighter public
carriages have been established; they have four wheels, are
drawn by one horse, carry nine passengers, and go between
seven and eight miles an hour: previously, the carriages
for the same number of passengers had two wheels, two
horses, and went slower.
There are somewhat less than 45,000 miles of high road
in Prance, over which it was reckoned in 1835 that seventy-
five horses in draught passed daily, exclusive of passenger
carriages, each horse drawing an average of one French ton,
(1,000 kilogrammes, equal to about 19i cwt. English,)
besides the carriage, and the cost of drawing of each ton per
league (about two-and-a-half miles English), was reckoned
to be one franc (10<2.). This would make the expense of
the draft of merchandise over the high roads in France
between 19 and 20 millions of money per annum.
* It is worthy of remark in the above Tables, how by the improved
mode there is an increase of road labour, and a reduction in consumption
of material.
n 2172
REMARKS ON THE MAINTENANCE
These French engineers calculate that there might be a
saving of at least one-third, say of £6,000,000 to the public,
by maintaining the roads in the best possible condition, from
that on which these calculations were made, which they
affirm may be done without a fraction of increased expense;
on the contrary, by a reduction in the expenditure on road
repairs.
So great an effect is not to be produced in Great Britain
and Ireland, because the high roads are not in so bad a con-
dition as they were in France when this calculation was
made; nor is the accumulation of broken stone so great as
to admit of abstaining altogether from the application of
fresh material for a considerable period, as appears to have
been very much the case in that country on the introduction
of this improved system.
But principally there is an advantage there in respect to
climate—the wet weather being only calculated at one-third
of the days in the year, and the dry at two-thirds; nor is
the material perhaps relatively so cheap as in Great Britain,
and consequently the saving on that item would be less in
this country.
Still there is very great room for improvement in the
system of maintenance of roads in the British Islands from
even the best now practised, which is by frequent patching,
to that of constant attention, determined prevention of the
collection of dust or mud, and the application of finely
broken stone, carefully blended in with the old in small
patches on the first appearance of inequalities or deficiency ;
and if the variable and more damp character of the climate
is unfavourable to the wear, and to the sweeping away of
the waste matter in shape of dust, it affords the advantage
at least of presenting greater opportunities, even in summer,
of applying the broken stone, which cannot be done during
dry weather without artificial watering.
The principle of unceasing and minute attention to the
road, requires a different manner of proceeding from that of
occasional working at intervals.
It will require men on constant duty for every part of each
district.
In England, men have been employed on this principle,
called milemen, and with great success.
In France it is very general, if not universal; they are
called cantonniers.
Such men must reside in the immediate neighbourhood ofOF MACADAMISED ROADS.	173
their district, and if possible they should be very near the
middle of it.
The milemen in England seem to he considered generally
as a class of gangsmen, and have labourers under them in
proportion to the work that may be required at different
periods.
In France the cantonnier frequently does all the work,
except on very special cases of need, and some importance
is attached to allotting such portion of road to each man as
he may be able to attend to by himself, and as will give him
full employment.
The advantages they propose by this is to render the
expense more regular—to encourage a spirit of pride and
emulation among them, and thus stimulate their ingenuity
and exertions; the entire and undivided responsibility resting
with each.
What with attention to drains, to the shape and trimming
of the road, to the removal of loose stones, and to very
frequent sweeping, preparing material after it may be brought
to the places of depot, and applying it where needed, (which
latter must be done in wet weather,) it has been found that
the work may be made constant and generally pretty regular
throughout the whole year.
Under the French system the extent of road given to each
man must be nicely regulated, so as to give him full employ-
ment, and yet not more than he can perform; and this
adjustment is one of the greatest difficulties in the system,
as the efficiency and economy of the maintenance will greatly
depend upon it; if the district be too large the man cannot
do justice to it; in that case, some mud, dust, or loose stones,
must be admitted, or inequalities allowed on the surface, the
question will be how much it ought to be, and the regulation
becomes indefinite and incomplete; if the district be too
small it will not be easily detected, as he will hardly confess
it, or perhaps even be aware of it.
The object of the preceding remarks is, to endeavour to
establish, that to obtain the best of roads requires much more
constant attention than is now bestowed upon them; and
that there is great reason to believe, that generally this may
be done without incurring any additional outlay.
That the drainage ought to be more effective ; and after
that is provided for, the two leading operations requisite are,
1st, Perfect cleanliness; that is, the removal of all dirt from
the road before it has time to collect in any sensible degree;174
REMARKS ON THE MAINTENANCE
2nd, The patching of every inequality, so as to preserve the
surface perfectly smooth, and to provide for the waste in
small quantities, and by material of the very best quality
that can be had, immediately that the most minute want is
perceived.
If a road that has four inches or more thickness of broken
stone upon it, is in bad condition, the proper process will
be, not that ordinarily pursued of immediately laying two
or three inches of fresh material along its centre, but to
commence cleaning it of the dust or mud, then to make good
the surface to an even and proper shape, pick’up all the little
hollows, fill them with patches of broken stone, and to pay
subsequently constant attention to those same operations.
OBSERVATIONS AND EXPLANATIONS.
The dirt will be removed chiefly by the broom, and will be
far more valuable as a manure for land, than what is now
obtained. By removing it rapidly, and keeping the surface
even and firm, there will be very much less of the stone
dust, which, except in limestone, causes poorness in the
manure; consequently it will consist chiefly of the dung,
dead leaves, and other extraneous matter deposited upon it,
which is in much greater quantity than would generally be
supposed. This may be illustrated by the dirt that is col-
lected, where there is much traffic even on the best pave-
ments, the wear of which is in this respect as nothing.
It is well known that the more clean and free from dirt
the broken stone laid on roads is, the better; by laying it
down in repairs on a dirty road, you are manifestly in-
fringing this rule, and mixing up with it a quantity of matter
that is thus acknowledged to be prejudicial.
The employment of the toughest and best material for
the broken stone is of far more importance on this than on
any other system; the reduction in the quantity consumed
will, under most circumstances, make up for the excess in
its price; and that reduction essentially lessens the amount
of every species of the work.
One great advantage of a hard even crust at all times is,
that it will bear far greater weights with equal thicknesses.
An instance is mentioned in one of the French works of a
load of nearly fifteen tons being drawn by 33 horses on aOP MACADAMISED ROADS.
175
carriage having wheels of inch tires, over three quarters
of a mile of a good Macadamised road of only four inches
thickness of metal, without leaving any perceptible trace;
therefore, a perfect road, kept to a habitual thickness of
eight or nine inches, will not only be sure to be perfectly
substantial, but will in times of need bear a considerable
period of wear and tear without fresh supplies of material;
and the reduction being very gradual, there will be a power
very much of regulating the labour connected with that
supply by the demand for it* Thus at present, the given
quantities of stone must be provided throughout every year,
and at precise periods, whereas, by the proposed mode, the
supply may be reduced in seasons, or for a whole year, when
labour is plentiful, and increased when there happens to be
distress for want of work.
Where roads are to be kept in such perfect condition by
minute attention over every 'part of the surface, it becomes
of much more importance that they should not be wider
between the water tables than may afford ample space for
the traffic; and not widening out irregularly, and without
any necessity, as may sometimes be witnessed.
It must not be assumed, in cases where a road is greatly
improved, and the outlay on it may remain the same, that
no saving is effected; because a necessary consequence of
an improved road will be increased traffic, and therefore the
expenditure will be less as compared with the service it
renders.
The cost, however, of maintenance of roads, as compared
one with another will, by no means, be always in proportion
to the amount of traffic; among other matters that will
influence it may be—nature of soil; hills; relative level of
road with the contiguous land; greater or less exposure to
the sun and wind; quality and price of broken stone, &c.
With reference to the regular roadmen as proposed, some
remarks occur.
. They may be selected from the most diligent, trustworthy,
and intelligent labourers; and as they should be retained
as a constant establishment, and on somewhat superior
allowances to the ordinary labourer, the employment will
create a sort of encouragement for that class.
The work, though constant, will be of a lighter, more
cleanly and healthy character, than that of the ordinary
day labourer on the roads at present, who is frequently day
after day wading in deep mud. In Prance they describe176	REMARKS ON THE MAINTENANCE
having some of these constant men (Cantonniers) at 80 years
of age, in employment on reduced districts; indeed, much
of the work is so light that even women or children may
assist at it.
The length of road under charge of one man may vary
under ordinary circumstances from one to three miles; in
narrow roads of very small traffic, this length may be
increased, and on great outlets to populous places, no one
man could probably undertake anything like one mile.
Experience in France seems to show that a man can
sweep in dry weather between 260 and 270 yards of road of
from 15 to 18 feet wide in a middling state, and double the
distance if in a perfect state ; suppose his charge to be one
mile and a half, he could therefore sweep it all over three
or six times per month, if the weather was dry, and he had
nothing else to do; in general, however, one or two
complete sweepings per month was found to be adequate.
Something may be said on the manner of operating on the
system here recommended, and on some of the tools that
have been found useful in this manner of maintenance.
Every little inequality or hollow in the road is to he
repaired very early and while it is small. It may be
observed that these are always of a round or oval form, and
therefore the square or rectangular patches which the
workmen are usually inclined to make of them are wrong,
and a waste of material.
Picking up the surface before the patching with new
material is only done to a depth of about half an inch,
rather more at the edges than in the middle, and if some of
the finer particles can be raised and laid over the broken
stone as blinding, the effect will be improved.
The stone for patching should be broken fine, (say to 1J,
or at most, 1% inch ring), of those broken to the dimensions
of 2 inches, one half or more will be sufficiently small, and
the rest can be reduced.
The use of a rammer and mallet is of great service on
new laid patches of broken stone. A rammer weighs from
11 to 22 lbs. with a surface of about 6 inches in diameter.
This is applied to the new laid material, and gives it a
certain degree of consistence; the impressions made by the
horses’ feet or by wheels are rammed to an even surface
again, which is far better than raking over the inequalities;
if the fall of the rammer is not sufficient, a mallet of similar
weight and surface enables a greater force to be applied.OF MACADAMISED ROADS.
177
Whether rammed or not, another description of mallet or
flattener is very useful; it is of from 18 to 22 lbs. in weight,
with a surface of 12 or 13 inches diameter.
These tools, though inferior to the roller, have been
employed very successfully in the consolidation, even of
new roads, thus: after the broken stone has been laid in
proper shape, a very slight sprinkling of gravel, or other
fine clean small stuff is spread over it; as the carriages
pass, the rammers are used to level the ruts and traces of
horses’ feet, &c., instead of raking. In this manner roads
have been brought into a firm, smooth state in two months,
when six were consumed to produce the same effect, where
not rammed.
Whenever loose stone is to be consolidated, it is abso-
lutely necessary that it should be wet; if the weather is
dry, there should be artificial watering. Even in patching
the road, the same should be attended to, if possible; at
least, the consolidation will never take place until there is
wet.
After a long period of dry weather, even good roads will
begin to loosen; watering and the rammer or flattener will
quickly put them to rights.
The dirt of a road is removed with most facility as dust;
the next most favourable state is, as very liquid mud,
because, in either case, a broom is sufficient for collecting it.
The best qualities of brooms for different circumstances
will be readily ascertained by experience, and no doubt
means will be readily found to make brooms of considerable
width, say two or three feet, either to be worked by hand
in the usual way, or on wheels, in order to facilitate the
operation.
The collection of dirt swept up must be very carefully
packed on the side of the road, in a manner to form no
impediment to the water draining off from the surface, and
should be carried away altogether very soon.
ON WATERING ROADS.
The laying of dust by Catering, as is the usual practice,
instead of removing it, is a pernicious and expensive system.
In the first place, it requires the frequent application of
large quantities of water, and forms at once a mass of mud,
h 3178
REMARKS ON THE MAINTENANCE
as may be frequently witnessed ; this mud tends to a more
rapid grinding and wear of the surface, while it lasts; but
during very dry weather it soon dries up, and requires the
operation to be again repeated. It is, in fact, instead of
removing the evil, substituting another for it, and one which
requires to be constantly renewed.
If the surface were hard, and the dust carefully removed,
a very light sprinkling of water might be applied to highly
frequented roads in dry weather, as a luxury.
It will be said, perhaps, and may be acknowledged, that
sweeping up great quantities of dust, would, in itself, be an
intolerable nuisance, but the object is to prevent any great
accumulation, by commencing as soon as it begins to form;
and the sweeping may be done either in conjunction with a
slight watering, or very early in the morning, when there is
little traffic, and little to be disturbed by it, and when the
dew of the night will tend to prevent its rising so much.
Where watering is practised there are few cases where a
very great saving in that costly operation might not be
effected, and applied to the removal of the dust or mud.
ON MACADAMISED ROADWAYS IN LARGE POPULOUS
TOWNS.
There may be doubts as to the policy of Macadamising
streets of cities and populous towns, on account of the diffi-
culty of perfect drainage; frequent wants of the full, free effect
of sun and wind; and impediment, by reason of the constant
great traffic, in the way of the necessary perpetual atten-
tion to the removal of waste matter and application of
material.
It is apprehended that a perfect pavement might be
cheaper and preferable, excepting in one particular, namely,
the noise; the wood pavement, if its peculiar inconveniences
can be surmounted, may prove best of all.
Dublin may be given as an instance of the effect of Mac-
adamisation in highly frequented streets.
The superintending engineers there appear to pay every
proper degree of attention to their duty;*the ordinary pro-
ceedings are practised, and yet it must be confessed that
the roadways are in a most unsatisfactory condition, and
anything but fulfilling the requisites of good roads, namely,
* See Note, p. 193.OF MACADAMISED ROADS.
179
being clean, hard, and even, at all seasons. On the contrary,
they are in winter, or wet weather, habitually covered with
mud, and in summer they would be as deeply overwhelmed
with dust, but for profuse watering; they have, in fact, at
all times, a thick coating of dirt on them, and mixed up
with the broken stone of their substance, to the very foun-
dation.
In winter, a large expense is incurred in scraping and
removing mud; but it is not sufficient to keep it under in
any essential degree. The nature of the work may be
judged of by the very name which is given to it, “ Scaven-
gering.” In fact, the men are nearly ankle deep in mud,
as they move to and from the line of stuff they are scraping
UP*
A small portion of the scrapings is sold as manure, at six-
pence and one shilling per ton; it is that chiefly which is
taken from the few paved streets; the remainder (from the
Macadamised streets) is carried away and deposited as
spoil at the expense of the Paving Board.
The watering, though not universal, is applied to almost
all but small streets. It is paid for in a separate rate by
the inhabitants of the streets who apply for it.
In summer, the roadway, excepting by being watered, is
left very much to itself, the only other operation being to
lay down occasionally patches of broken stone where the
surface gets so bad that it cannot be delayed.
The result of the laying down the stone at that season
(and sometimes necessarily in very dry weather), occa-
sions great inconvenience and waste. The horses and
carriages when forced upon it suffer in consequence. The
material will not, in spite of the watering given to it,
consolidate for very long, but some is cast about loose, and
much is crushed ; in fact, unless it crosses the whole way,
it acts chiefly as a beacon to warn carriages, as long as
possible, from those parts.
The material is, however, chiefly laid down in winter, and
is gradually consolidated by the traffic, commencing in the
ordinaiy manner along the edges; but by such means, and
surrounded by mud, there is a very great loss before the
portion that ultimately remains becomes fixed.
It can hardly be doubted, but that means might be devised
for greatly improving on this system, and obtaining better
roadways, even at the same expense.
It would not be easy to define at once, in every particular,180
REMARKS ON THE MAINTENANCE
exactly how it is to be done; but it might be worthy of
experiment.
The two principal measures to be adopted or ameliorated
are—
1st. To keep the roadways always clear of any
collection of dirt upon them.
2ndly. To fix on the means for laying down, in the
most advantageous manner, the broken stone that will
be necessary to maintain adequate thickness for bearing
the traffic.
First,—with regard to the cleaning, it will be done chiefly
(it may be hoped, entirely) with the broom; it will perhaps
be difficult to be executed amidst all the traffic, but not so
much so as would appear, judging from the present state
of the roads; because it is contemplated that at no time
will there be more than a very slight quantity of dirt to
remove, and that chiefly of the matter dropped upon the
surface.
It is impossible exactly to foresee how often each part
will require to be swept over; the most frequented thorough-
fares perhaps daily, others from that to once a week, or
even ten days, the least being on those that are paved and
least traversed.
It is to be understood that this operation will take place
in summer as well as winter, in the driest as well as in the
wettest weather, though perhaps not so often.
How the sweepings are to be put together and carried off,
will be another arrangement for experiment; the point will
be not to waste horse hire by keeping the carts lingering
all day over perhaps two or three miles, yet at the same
time so to dispose of the mass collected in the street, as
not to be in the way of the traffic, or scattered about, until
the cart shall come round for it.
It is suggested that any medium course of partial
clearance, that is making the streets somewhat more clean
than at present, would certainly lead to failure, it would
cause an increase of expense in one item, without a com-
pensating reduction in others ; it must be the endeavour to
keep perfectly clean, and free at all times from mud or dust,
whatever parts may be submitted to the operation, so that
every wheel may roll over the hard compact surface of stone
alone.OP MACADAMISED ROADS.
181
This can only be partially effected on the present road
surface, the whole mass is so deeply mixed up with dirt,
hut may he done perfectly after every successive general
spreading of broken stone hereafter.
If these streets were constantly kept perfectly clean,
hard, and even, and the material was of a tough good
quality, the actual wear of the surface would be extremely
small, less, no doubt, than an inch in the year, even in
those most frequented; the wheels in fact would be running
over a smooth pavement made of small materials.*
Still, even at that rate, it would be more convenient,
where the intercourse is nearly incessant, to have the
supplies laid down occasionally in general masses, in prefer-
ence to the course recommended for roads under other
circumstances, by minute repairs exclusively; because in
this case the small additions would be too frequent and
general, and more especially because in towns the more
extensive spreading of broken stone can without difficulty
be greatly consolidated at once by rolling.
It is suggested that the thickness of consolidated metal-
ling need never exceed about nine inches, nor ever be less
than four or five; when reduced to that minimum the
surface should be loosely picked, and about four or five
inches of broken stone laid along the street, and most
completely rolled, with the necessary binding on the most
approved system.
it is indispensable that it should be made thoroughly
firm, and would then bring the outer crust from four or
five inches to eight or nine, according to the importance of
the street.
The new laid material must be well attended to, and
rolled until it is perceived that it is perfect in form, and so
solid that neither wheels nor horses’ feet make injurious
impression on it.
This will be the substance for regular wear, and it is
calculated will last two, three,* or more years; small de-
pressions, inequalities, or want of form, as soon as they can
be perceived, being minutely corrected from time to time,
by picking the surface, and then patching with small
quantities of stone broken fine.
There are 76 statute miles of streets under the Paving
* The wear of surface on a road of great traffic, kept very firm, even,
and clean, in France, was found to be less than half an inch in the year.182
REMARKS ON THE MAINTENANCE
Board, of which 52 of the most important are Macada-
mised, and 24, chiefly inferior thoroughfares, paved.
The expense of their maintenance in the year 1842, ex-
clusive of sewers and footway, flagging, &c., was—
For Macadamisation and Paving .	. £11,036
„ Scavengering......................7,394
„ Watering .....	1,842
£20,272
From the first item about £4,450 may be deducted as
the expenses of the paved streets, of crossings, gravel, &c.,
leaving £6,586 for the Macadamisation.
Thus we have £15,822 for the cost of maintenance of the
streets, exclusive of paving, crossings, &c., which may be
supposed to remain as at present.
With regard to the relative expense of the system now
proposed, as compared with the above, we shall have the
following items of increase.
1.	The street labour, in sweeping, keeping them clear
of loose stones, and of all deposit or extraneous matter,
patching the little inequalities that may occur, and
general attention.
2.	Foiling thoroughly at the times of the general
laying down of material.
1.	The first will require a very large expenditure to give
it full eflect.
The great leading streets may require an average of one
man for every 200 yards—less in summer and more in
winter; others will not require so many, gradually reducing
down to the smaller paved streets, for which one man per
half-mile, or, perhaps, even per mile, may be ample.
Suppose then an average throughout the year of about
four per mile; 300 men daily would be employed in this
service, which at Is. M. each would amount to £6,260 per
annum.
Then suppose 20 one-horse carts daily, for the removal of
the sweepings, at 4s. Qd. the cart, would amount to £1,40810s.,
making £7,668 10s. for this most material item.
2.	For the rolling, estimating the general laying down of
broken stone over every part of the Macadamised ways toOP MACADAMISED ROADS.
188
take place, we will allow 20 miles to be rolled per annum ;
the average width of the streets are 82 feet, and the cost
conseauently may be £38 per mile, or £760 for the 20
miles.*
Add this
To the above Estimate
The Amount will be .
Which deducted from
.	.	.	£760 0 0
.	.	.	7,668 10 0
.	8,428 10 0
. 15,822 0 0
Leaves for Broken Stone and Watering, £7,393 10 0
The latter will be greatly reduced; but leaving it as
before as an extraneous charge, namely, £1,832, there will
remain £5,552 10s. for broken stone.
The cost for this item is now about £5,700, but it is one
m which there must be a very considerable reduction, at
least equal to one half, when the system is thoroughly acted
upon; say that the cost should then amount to £3,000,
there will remain £2,500 for contingencies, or to make good
any deficiencies in the above calculations, which, however,
it is believed are by no means forced.
There will be an item of increase in the available funds,
though not large, in the sale of the street sweepings, which
will be all valuable manure, and a saving in the necessity
for carrying any to spoil.
Where road work is to be done as proposed, chiefly by
daily labourers, it is a matter of consequence so to adjust
the work as to require a constant and uniform supply; this
is done now in Dublin very much by working at the paved
streets, when less is required on those that are Macadamised,
and such arrangement may be continued.
* Vide Paper on Road Rolling, over leaf184
REMARKS ON THE MAINTENANCE
ON ROLLING NEW MADE ROADS,
The importance of rolling roads, either newly constructed
or when subjected to extensive repairs, seems never to have
been duly appreciated.
Lines of any length of new laid broken stone may be
deemed nearly impracticable to ordinary traffic; the worst
and most hilly old roads are always taken in preference to
the new roads while in that state, although the latter may
be much shorter, and with very improved levels.
At length the old road is shut up, carriages are forced to
take the new, occasioning the greatest inconvenience and
drawback to the intercourse for perhaps a year or more, a
great wear and waste of the material, and a considerable
expenditure in watching and maintenance, until the material,
or what remains of it, shall be finally consolidated, and even
then in a very imperfect form, unless great pains are taken
with it.
The rolling is, in fact, effected, but in the most distressing
and expensive manner, and by carriages and horses very ill
adapted to it.
These evils may be entirely prevented, the road put at
once into good working condition, and, certainly, a consider-
able expense eventually saved, by thorough systematic
rolling; nor ought any road to be considered as made until
that operation shall be completely effected.
Three reasons have probably operated to prevent this
principle having been acknowledged and acted upon.
1.	Because the traffic on the road will, sooner or
later, do the work, thereby apparently reducing, in a
small degree, the cost of the original construction or
repair.
2.	Because a roller is not usually at hand, and from
its weight and unmanageable character, it is most incon-
venient and expensive to be removed from one place to
another, so that in most cases one would have to be
constructed for the purpose, and then be useless.
3.	Much uncertainty, as yet, as to the best manner
of operating, its efficacy, and the expense.0* MACADAMISED ROADS.
185
The first reason is founded completely on error; it is
manifest that this manner of completing the road by the
traffic is most inconvenient, and occasions enormous sacri-
fices by the parties using the road, and consequently a great
loss to the public in general; nor can there be a doubt but
that the actual expenditure on the subsequent early mainten-
ance of the road itself is greater than would be incurred by at
once operating thoroughly with the roller.
With regard to the second reason, there are many ways
in which the objection can be greatly alleviated.
Although there is some justice in the third, and that the
most perfect mode of proceeding is not yet perhaps under-
stood, there is so much useful effect to be produced by any,
that it is surprising that it has not been reduced to just
principles by experiment, and generally adopted.
The practice of rolling has been rare, and almost entirely
confined to gentlemen’s demesnes, and occasionally to the
Macadamised roadways in some cities; but in the latter, it
is believed, without the application of sufficient means for
the purpose.
There are certain considerations which may serve as guides
to arrive at just conclusions with regard to this proceeding.
1.	A roller should not be too heavy in proportion to
its bearing surface, or, instead of binding the material
in the position and form laid down and desired, it will
press it more or less into the substratum; much of the
material will thus become useless, and it will be very
troublesome to obtain the necessary resistance for the
consolidation.
2.	It must not be too light, or the effect will be too
(small ever to gain the object fully; or at any rate with-
out an extent of operation that would be very costly or
inconvenient.
It is believed that the ordinary rollers are too light,
which may have thrown the practice into disrepute.
Dor the Dublin streets they have a roller of two con-
tiguous cylinders, each of 4 feet diameter, and 1 foot
6 inches in width, making in all a bearing of 3 feet; it
weighs 2 tons 3 cwt.; only two horses are attached to it,
but the work is exceedingly heavy. It is applied to suc-
cessive layers of material, in new formations, and about
an inch of gravel is worked into the upper layer or
surface. It is said to consolidate the roadway very186
REMARKS ON THE MAINTENANCE
effectually, but might probably be improved by adding
to its weight.*
Prom other recorded trials, however, there is reason
to believe, that a road roller should not be lighter than
28 cwt. for every 12 inches lineal of bearing on the road;
that is, if 4 feet wide, that it should weigh 5 tons 12
cwt.; if 8 feet, 4 tons 4 cwt., &c.; and that it should
only be applied to the upper surface of all.
A roller somewhat heavier than 28 cwt. per foot would
be more effective, but it is better after that limit to gain
the object rather by adding to the number of times
passing over the surface, than incur the inconveniences
of the heavier machinery.
This is one very interesting point to prove, namely,
the relative effects of light and heavy rollers, taking into
account the number of turns required by each.
3.	For effect, the wider a roller can be, the better,
because the operation will be more quickly performed,
and because, in proportion as it is narrow, will there be
a tendency to force the broken stone laterally from
under its action; but, as the weight must be in propor-
tion to its bearing surface, the width must be limited
to a degree that will prevent that weight being too
unwieldy; a very narrow roller might also have a
tendency to overturn. On the other hand, one that is
very wide may take up too much room, if the road is
open to traffic during the time of its use.
4.	Horses should not be obliged to use very great
exertions in drawing a roller, or the action of their feet
will discompose the loose stones very inconveniently;
therefore, as the draught is very heavy at first, and
never very light up to the last of the operation, they
should not have more than from ten to twelve cwt. each
to draw at first, nor so much as a ton each at last.
5.	It would be desirable not to put more than four
horses to such a machine, because, as the number of
horses are multiplied, it becomes more difficult to obtain
a perfectly united effort from them; but on the above
data a roller of four tons maximum weight might be too
small for the best service, and as six horses may perhaps
* A short street (Herbert-street), made in 1836, and then well rolled,
has never required repair or new material since, up to 1843 ; it is a good
street, but not entirely built on, nor a great thoroughfare.OP MACADAMISED ROADS.
187
be applied without much inconvenience, it is proposed to
give that number as a limit, and to allow 5 tons 12 cwt.
as the maximum weight for the roller; this, at 28 cwt.
per foot of bearing, would give it a width of four feet.
From the Continent we have records of several trials that
have been made of late years of the effect of rolling new
laid material on roads; although there are discrepancies
in some of the particulars, there are many in which all agree;
and in all the practice has been strongly recommended.
The one that seems to be the most practical is a roller
described as first used in the Prussian provinces on the
Rhine, and from thence introduced with some modification
into a neighbouring district in Prance.
It consists of a cylinder of cast iron of about 4 feet 3J
inches wide, and 4 feet 3| inches diameter * On the axle by
means of iron stanchions is fixed a large wooden case of 6 feet
4| inches long, 5 feet 8| inches wide, and 1 foot 8 inches
high, open at top.
This roller has a pole before and behind, in order to be
able to draw it in either direction without turning; the hind
pole is sometimes used to assist in guiding it. It has also
a drag, by the pressure of a board on its face, in the manner
used for French waggons.
The cylinder and other iron work weighs nearly 2 tons;
the case and woodwork about 19 cwt., making the whole
2 tons 19 cwt.
The case will contain a weight of stone of 2 tons 19 cwt.
when completely loaded; therefore the entire weight can be
brought up to 5 tons 18 cwt.
Six strong horses worked it well.
It is passed over the entire surface of the road once or
twice without any loading, weighing consequently nearly
three tons, to obtain a first settlement of the loose material;
then one or two turns with about 1| tons loading, making
4J tons; and then the last turns, making ten in all, with
the full loading, when it becomes 5 tons 18 cwt.
Traversing 12 miles, it will thus completely roll about
3,000 square yards t in one day, or about a quarter of a
mile of a road of 21 feet width.
* These and other dimensions are necessarily in odd numbers, owing to
reducing them from French measures and weights.
+ Some of the calculations are not strictly in accordance with the data,188
REMARKS ON THE MAINTENANCE
All accounts agree as to the absolute necessity, and the
best manner of applying some gravel, or other sharp, gritty,
very fine stuff on the surface, during the operation, without
which it will not be thoroughly bound.
The consolidation commences with the lower part, which
is the first to get fixed and arranged; and when, after about
six turns over the whole, the upper layers have become
tolerably firm and well bedded, some sand or stone-dust, or,
what is best of all, sharp gravel, is very lightly sprinkled
over it by degrees at every successive rolling, solely for the
'purpose of fitting up the interstices of the broken stone, and
not to cover it; about 3 cubic yards in the whole per 100
square yards (equal to about an inch in thickness if spread
over the whole surface,) will be required. It is essential
that this small stuff be not applied earlier, or it will get to
the lower strata, and not only be wasted but injurious; the
object is that it should penetrate for two or three inches
only, to help to bind the surface.
Provided the upper interstices are filled, the less gravel
used the better; therefore it is applied by little and little
after each of the three or four last successive passages of
the roller, and then only over the places where there are
open joints.
After the work, if well done, is completed, it is stated
that such is the effect, that the upper crust may be raised
in cakes of six or seven square feet at a time, which could
never be without the gravel.
The effect may be improved also by having the upper inch
or two of stone finer than the rest, say to pass a ring of 1J
inch or 1% inch.
This work should be done in wet weather, or the material
will require to be profusely watered artificially.
It will be better that it should not absolutely rain, unless
very lightly, when the gravel is applied, (although the stoning
should be wet,) as it will cause it to adhere to the roller,
and even at times to bring up the broken stone with it.
In frost it is of no use attempting to roll. The state of the
material, as regards its being wet or dry, will have great
influence in the success of the operation.
The form of the road will be best preserved by rolling
because the data themselves are not given in minute fractional parts, and
consequently the reduction of the results will show a difference; but it is
very small and of no consequence in a general consideration of the matter.OF MACADAMISED ROADS.	189
from the two sides towards the middle, and not commencing
along the latter.
The calculated expense of the work in France was—
For six horses and two drivers per day £14 0
For six labourers attending on the road,
assisting at the roller, levelling in-
equalities, spreading gravel, &c.	.070
Total for 3,000 square yards . £1 11 0
Being about one penny for eight square yards, or one penny
per running yard of road, twenty-four feet wide, and will
amount to about £7 5s. per mile.
For Ireland, these prices would have to be increased,
thus—
For six horses, with drivers, per day .£170
For six labourers, at Is. 4c?.	.	.	0 8 0
£1 15 0
It is considered that a modification would be desirable in
this foreign roller, by making it only four feet wide; its
weight might then be, with its box for the additional loading,
&c., about tons, which with an extra loading of 2 tons
2 cwt. would bring it to the 5 tons 12 cwt. for its extreme
weight, at 28 cwt. per foot.
Such a roller passing ten times over every part, and
working twelve miles per day, would require five days, and
the operation cost about £8 15s. per mile of road, of twenty-
four feet wide completed.
The gravel ought to be considered as material, but in this
case it is an addition to what would otherwise be applied;
the cost therefore must be added.
Suppose it to amount to one shilling per cube yard, the
expense, at thirty-six square yards per cube yard of gravel,
will be about £19 5s. per mile of road of twenty-four feet
wide.
This would bring the whole to an amount of £28 per mile.
However perfect the rolling may be, there will be at the
end a slight elasticity and yielding of the surface, which will
only become quite firm and hard after some days’ traffic, say
from six to ten when tolerably frequented, during which its190
REMARKS ON THE MAINTENANCE
form and smoothness must he carefully attended to; add,
therefore, £2 per mile for that extra work, and the cost will
he £30 per mile.
The expense of the operation of the roller (independent
of the gravel) is so small, that if the weight is under-
estimated, so that the width of the roller should require to
be reduced to three feet, thus adding one-fourth to that part
of the outlay, or that it would require to be passed a greater
number of times more than calculated, that increase would
not be of essential importance on the gross amount.
If artificial watering should be necessary, that expense
also must be added, but it would be small.
The subsequent wear of material, under proper care, will
be most trifling; one Erench engineer states, that where the
rolling in this manner has been successfully performed, there
has never been a necessity for applying above one cubic yard
of broken stone per 300 square yards of road in the next year;
that in one instance only one cubic yard per 1500 square
yards was used, although on a road subject to the passage of
400 horses in draft per day; and on another road no fresh
stone was laid for three years.
To make a more direct comparison, however, of expense,
it may be assumed that a much greater diminution of thick-
ness will take place in the consolidation by the traffic than
if effected at once by the rolling, because the narrow wheels
of ordinary carriages penetrate into the loose matter, and
force the lower part of it partially into the subsoil. The
displacement and grinding and crushing is also very great;
whereas, in rolling, the entire is preserved and in its proper
place; it may therefore not be too much to estimate, that if
it require ten inches of loose material to bind into six inches
by the ordinary process, as it probably would; eight inches
well rolled would give the same; if so, the saving at once
would be very great; thus, suppose the covering of one inch
of stone to cost as much as two inches of gravel, that is, if
the gravel is valued as above, at Is. per cubic yard, that the
stone be valued at 2s.; then we have four times the cost of
the gravel, which was stated to be £20 per mile, or £80, to
set against the £30, estimated expense of rolling.
If the rolling effected a saving of only one inch of the
broken stone, still the cost of that one inch would exceed
that of the rolling, including the gravel.
This last calculation is given only as a proof of the saving,
and not as recommending the reduction of the mass of mate-OF MACADAMISED BOADS.
191
rial laid down to a minimum; on the contrary, as tlie rolling
of the surface is a final measure, and requires no renewal
until the road is worn to a minimum thickness, the most
economical plan probably would be to apply a considerable
degree of substance at once, enough to last some years, so
as to reduce the number of periods when rolling would be
necessary.
A roller, on what is here assumed to be the best construc-
tion, namely, of 4 feet bearing in one cylinder, and weighing
2£ tons, would not be very convenient to move from place
to place, for any considerable distances; an idea was there-
fore suggested of constructing one as a cart, on two wheels,
the tires of which might be of 9, or 12, or 18 inches in
width. Such a machine would weigh from one to two tons.
The axle might be bent, and under the body, or might be
straight, and pass through it, so that the loading of two or
three tons might lie very low. The distance between the
wheels should be a certain number of times the width of the
tires; namely, if the latter are 9 inches, the distance
asunder might be 3 feet, or 3 feet 9 inches; if 12 inches,
they might be 3 or 4 feet, and if 18 inches, 3 feet.
Such a roller might be very convenient in many respects,
but would be subject to two objections:
1st, The tendency to force the material laterally from
under its pressure, by the little width of each roller.
2nd, The impossibility by successive passages of giv-
ing every part of the road precisely the same amount
of rolling; some parts must have more turns than
others.
In some few situations the very formation of the road may
be made subservient to its rolling.
In the construction of a new road over the Carey
mountain, in the County of Antrim, material for stoning
the road was quarried in several parts of the mountain up
to its summit.
Some carts were made with wheels of four inch tires, and
the laying of the broken stone being commenced close to the
quarry, the work was carried on from each quarry down
hill, the loaded carts being taken over the new laid material,
working systematically over the entire width of the road,
and discharged below, returning up the hill light. By the
time the work was completed the road had acquired in this192 THE MAINTENANCE OF MACADAMISED ROADS.
way a considerable degree of consolidation without extra
labour.
A roller of the weight of five or six tons may be worked
up inclines of one in twenty by increasing the number of
horses, but not steeper; if at all exceeding one in thirty it
would probably be better to apply the roller in its lightest
state, and increase the number of passages.
It is very desirable to complete rapidly what is once
begun, but it is attended with the disadvantage of taking
up short lengths at a time, which leads to the occasion for
turning the roller very frequently, a manoeuvre that is par-
ticularly inconvenient.
Although certain dimensions and weights are suggested
to be likely to prove the most efficient, any other kinds that
happen to be in possession might be tried and adapted to
the above principles, which will usually require weight to
be added with the successive rollings; this may be done io
various ways according to circumstances and situations; the
most simple, but most cumbrous and troublesome of appli?
cation will be a large case on the roller, for loading with
stone.
In or near towns, iron weights might be used instead of
stone, partly on or suspended to the axle, within the
cylinder, or in a case outside, which might be then much
smaller, and the weight be more compact and more easily
shifted; or for use in a town, when the most efficient
dimensions and weights were ascertained, rollers might be
prepared of two or three qualities, that is, all of the same
extent of bearing, but of cylinders of different weights,
from the lightest to the heaviest, and brought in succession
on to the work.
Jy E. B,Note to Page 178.
The Causes of apparent Failure of Macadamising in cer-
tain Cases. By Robert Mallet, M.A., F.R.S., C.E.
The views given in the text, at p. 178, as to the wisdom or
not of employing Macadamised roads in populous cities,
admit of being strongly contested; and a formidable array of
facts as to the successful and economical employment of such
roads, even under the heaviest and largest metropolitan or
other traffic, can be adduced in opposition to them.
As the distinguished author has adduced the streets of
Dublin as an example of the unsatisfactory results of Mac-
adamisation, it would be an injustice to the student to with-
hold from him the mistaken basis upon which Sir John F.
Burgoyne has arrived at some of his conclusions, when he says
that " in Dublin the superintending engineers there appeared
to pay every proper attention to their duty,” and that “ the
ordinary proceedings are practised.” With the fact that the
street surfaces of Dublin were, at the time Sir John wrote,
and continue to a large extent still, “ as roadways in a most
unsatisfactory condition,” we are fully5 prepared to agree.
We must deny, however, that their condition has ever arisen
from any inherent defects in Macadamising, or in its unsuit-
ability to traffic, even if immeasurably heavier, and more
frequent and rapid, than the comparatively small and light
traffic of Dublin; and we will venture to point out, from
intimate local and personal knowledge, some of the causes
that really have produced the sad and disgraceful state and
history of the Dublin streets; and, in so doing, shall be able
to show that neither have those in charge of them compre-
hended or done their duty, nor practised such ordinary
proceedings as competent road makers would approve. To
these causes alone the former state of the Dublin streets is
attributable.
For a long period prior to about the year 1829 or 1830, and
long subsequent to it, the management of the streets of Dublin
was intrusted to a Board, called the Commissioners of Paving.
This Board consisted of three members—how chosen we
know not—but, at the period referred to, one, the chairman,
was an alderman, and had been a linendraper, and another, a
half-pay infantry officer; the third, so complete a nonentity
K194
ON THE CONSTRUCTION OP THE
that we forget him altogether. The streets of Dublin, or at
least the chief portion of them, were paved for the first time
under the direction of a Major Taylor, who, though not even a
military engineer, was said to have been a competent man.
They were paved according to old practice, sanctioned by that
of old France, with round nodular natural paving-stones, or
“boulders,” taken from the beds of rivers, and from the gravel
pits of the County Dublin, and consisting chiefly of the soft;
shaly, argillaceous limestone of that part of Ireland, locally
called “ calp.” The water kennel was generally in the middle
of the street, the surface of which fell towards it from both
aides ; and this nodular pavement was laid, without any pre-
paration of the substratum whatever, directly upon the earth
and clay* merely levelled. Inherently bad, this wretched pave-
ment had been for years so neglected, the sub-soil in the wet
climate of Dublin had been so driven up as mud through the
open joints of the ovoids of stone, and so rutted the surface,
that the streets in 1829, or thereabouts, were nearly im-
passable. A fine opportunity for making a grand coup for
popularity presented itself to the Commissioners, by the
sudden apparent improvement of the streets, by converting
this bad pavement, with all its noise and filth, into smooth
and silent Macadamised road. Had this been properly done,
the work would have beep a lasting monument to their
honour; as it was done, it has left a legacy of bad streets to
Dublin, and a proof of the utter incompetency of those Com-
missioners; and, unfortunately, none of their successors
have had the skill to rectify their mistakes, or even to com-
prehend them.
The conversion was made as follows :—The paving-stones,
as they lay, were struck with a sledge and broken into three
or four large fragments; these were picked up, laid aside, and
broken into heaps of road metal. About three or four inches
of coarse ^nd fine unscreened pit gravel was spread over the
surface bed of clay out of which the pavement had come, in
some cases; in others, none was used; and upon either one
or the other surface a very little greater depth of road metal
was spread than was produced by the breaking up of the
paving-stones that had been removed. Neither drainage
of the surface, where wet and soft, nor any sound bottoming;
nor, in one word, a single necessary measure for the forma-
tion of a good permanent Macadamised surface, was observed.
The quantity or depth of the road metal was utterly
inadequate, and the quality pf its material was vile—for, inSTREET SURFACES OF CITIES.
195
faet,the“calp,, limestone is nothing but consolidated black
mud, often not much harder than Portland stone, and which
grinds away into mud and dust, like so much dry cheese.
For the first time the citizens of Dublin tasted, momen-
tarily, the joys of silent and smooth streets, with a rounded
cross contour, in place of slipping and floundering over
lumpy nodules, and splashing through filthy mid-stream
kennels of five feet wide—and, for the time, “ great were
the Commissioners of Paving ” in the public regards. But,
after a very few years’ trial, even under the light traffic of
Dublin, the whited sepulchre'began to show its real colours;
the thin unbottomed crust of Macadam got worn through, and
most unequally; and the then “ superintending engineers,” of
whose professional abilities the less said the better, exerted
themselves “with every proper degree of attention to their
duty,” to do—what ? Not to repair each street, seriatim, as they
might and ought to have done, by beginning again at the be-
ginning, taking off and carting away the whole worthless surface
to fourteen inches deep, or more, and laying down a properly
bottom-drained and formed road, and employing proper
material for the road metal; but in continually heaping on and
incessantly spreading, at all seasons of the year, wet or dry,
more and more of the worthless “ calp,” got either from gravel
pits, river beds-, or quarries, and broken into most uneven and
irregular and far too large road metal. The more of this was
laid on, the more mud was produced upon the streets, as it was
ground up by traffic. The scavenging of the streets was, as
well as the paving, under the sapient direction of “ the Com-
missioners,” who could only hold up their hands in amazement
at the (to them) unaccountable fact that the annual cost of the
scavenging continually increased, and that the more “ calp ”
road metal they spread upon the streets the more mud they
had to cart away. About 1842 things had reached such a
pass that a Dublin Improvement Bill, known commonly as
“ Jackson’s Bill,” from the name of its chief promoter, was
introduced in Parliament, for the purpose of taking away all
powers, both from the Paving Commissioners and the Cor-
poration of Dublin, and vesting in a new body the water
supply, to be given by means of new works ; the sewerage
(involving at that early day intercepting main sewers, quite
similar to those now executing in London), the paving,
lighting, and scavenging of the streets. The writer was him-
self the engineer to this Bill, and prepared the designs for the
new works intended under its powers. According to the196
ON THE CONSTRUCTION OP THE
method of parliamentary proceedings at that time, a “Local
Inquiry Court ” was held at Dublin ; the evidence given be-
fore which is on parliamentary record, when not only the
preceding general facts were proved, but the following also :—
1.	That year by year the total quantity of “calpM road
metal spread upon the streets had been increasing
rapidly.
2.	That year by year the annual charge for scaveng-
ing had been increasing rapidly. .
3 That the quantity of mud taken off the streets
annually was much larger than the amount of road metal
laid on.
4. That the surface of the streets was in gradual
process of being lowered (as a consequence), and that,
in most cases, all original fall between the centre and
side kennels had disappeared.
The Professor of Geology of the tJniversity of t)ublin, now
Director of the Geological Survey of India, who had himself
been educated as a civil engineer, and had had some experi-
ence in road-making, deposed that the material employed for
the road metal, “ calp,” was, in his own words,“ only consoli-
dated mud,” and rapidly returned to its original condition under
traffic; while he also showed that abundance of fine hard
whin stone, sienite, and other fit rocks could be had in Ireland
at a most moderate rate, from which the very best road metal
might be broken* Independent witnesses produced average,
samples of the style in which the road metal (irrespective of
its material) wasbroken, and showed that, on the same surface,
lumps as big as a fist Were mixed indiscriminately with those
not bigger than Walnuts; that the streets were never free
from sheets of loose stone, that it was laid upon them at all
seasons, that the surface beneath was never picked up before
spreading new stone, that the surfaces of new-laid metal were
never blinded with sand, nor any other measure taken to in-
duce early and even traffic over them; that the mud from the
old street surface was, however, frequently thrown over the
face of the new surface of stones as a blind (in every sense),
and as the easiest mode of getting rid of it; and that in very
wet weather the grand resort and expedient of the scavengers
(for the economy of their own muscles and of the public purse,
no doubt)was to sweep the mud out of sight down into the
sewers. Much more there was proved, grotesquely absurd in
mismanagement, which it is needless here to recount. OneSTREET SURFACES OF CITIES.
197
point, however, is too good, as showing the calibre of the
parties concerned, to omit. The chief defence of the Com-
missioners was this: that they continued to lay on “calp,”
bad road metal, because the scavenging mud was thought
better as a manure, when produced from that, than from whin-
stone or sienite; it having been proved by them previously
that they could scarcely sell this mud as manure at any price,
and that it had accumulated in such mountainous masses, that
they had actually had to purchase the fee-simple of some large
pieces of ground in order to get space for “ depdts” to deposit
it on.
In a word, it was demonstrated that, as things then were
going, in but a few years the whole £47,000 a year, which
constituted their funds, would be inadequate to supply the
“ calp,” lay it on the unbottomed streets, and cart it off again
as mud.
Were these “ ordinary proceedings, with every proper at-
tention to duty ? ”
The “ Jackson Improvement Bill” was thrown out by
Government, which had already determined, for political
reasons, upon their own reform of the Municipal Corporation
of Dublin; and not very long after this reform became law,
and the functions of the “ old Paving Commissioners ” passed
into the hands of the present Corporation of Dublin, their
borough engineer becoming charged with the duty of main-
taining the streets.
For a good while after, however, the old system went on
nearly unaltered. That officer neither possessed the pro-
fessional statm nor the personal influence due to commanding
ability, nor had his masters, the members of the Corporation,
the clear-sightedness and courage, to boldly inaugurate a
new system. While they squabbled in the town council
upon “ Repeal and Polemics ” and “ Protestant As-
cendency,” and lost the confidence of every honest citizen,
they had neither time nor brains for setting the civic ways in
order. Patriotism was their trade and vocation, not sedileship.
After a while the streets got even worse than ever; men
spoke in public in Dublin, and letters were written in the
papers, lamenting the loss of the poor old imbecile Com-
missioners, and declaring the streets, under the reformed
Corporation, would soon cease to be passable at all.
Persons carried on “ Irish cars ” were, in several instances,
chucked off by suddenly plumping into ruts, and in one
case of severe personal injury thus resulting, action at law198
ON THE CONSTRUCTION OF THE
was threatened. Something must be done, sothe borough
surveyor was sent for, and he advised that the only remedy
was to go back to pavement; nothing, he declared, could
be done to improve the Macadamisation. There was no
fault (that he could see) to be found with the way it was
done, and it would never be better. Somebody said that
wicked opponents had hinted that “ calp ” was bad stuff—-that
whinstone ought to be used. “Tell me where I am to get
it,” replied the surveyor, “ and I will try it—though I don’t,
I am sure, see the good of it.” And now the geologists came
out again, and declared that plenty of good whinstone might
be procured at a place only seven miles from Dublin. After
a little, some wedgy, ugly, ill-broken, splintery sort of light
“ green stone ” began, in some places, to make its appearance
on the surface of the streets, and at once proved itself, in
many ways, worse than the “calp.’* Again the geologists
wrote in the papers : “ What is this horrible stuff you have
been putting on ?” “ Why, is it not the whinstone from the
Big Hill of Howth, that you yourselves insisted upon, and
said was the right thing ? ” replied the surveyor. “ Cer-
tainly not, Mr. Engineer,” rejoined the geologists. “ What
you have mistaken for whinstone is nothing but green
metamorphic clay date, which is also found at Howth as well
as the whinstone.” So the discomfited functionary went back
and assured the Corporation that paving was the only thing
to take him and them out of the scrape. An experimental
piece of paving was accordingly ordered to be laid down,
and the surveyor recommended County Dublin wljite granite
as the best material.
Grafton-street, one of the “car drivenest” streets in Dublin,
was soon paved with huge blocks, nearly seven inches thick;
and, to perfect the resemblance to voussoirs, the surface of
the street, which is not more than 35 or 40 feet wide, was
given a round of about eighteen inches between centre and
kennel. The County Dublin granite is some of the softest
and richest in mica and magnesian minerals of Great
Britain. It very soon wore into pits and holes, and at once
became so slippery that horses literally could not keep their
feet upon the sloping and “gliddery” sides of the hog-
backed pavement, and so the whole had, nolens volens, to
come up again. We believe it was actually laid a second
time with the same granite, but in moderate-sized blocks,
and with “ a round ” on the surface somewhat less prepos-
terous. About this date the state of the Dublin streets forcedSTREET SURFACES IN CITIES.	199
itself upon the notice of some of the county surveyors of
the adjoining counties, and one of these gentlemen, who well
Understood the road-making branch of his profession, read a
paper Upon the subject and drew on some discussions of it
at the Institution of Civil Engineers of Ireland.
The author of that paper did more, however; he backed
up his views as to the stupid mismanagement of the Dublin
streets by publicly offering to take a contract for them—
restorations, maintenance, and repairs—at an annual rate
greatly below what they were admittedly costing.
But this would not suit “ the patronage ” book of the re-
formed Corporation, still less was it acceptable to their borough
officers. So the paving proceeded, and got a new impulse.
The surveyor had learned, and apparently for the first time
during the discussions at the Institution of Civil Engineers,
that Dublin granite made bad paving, and that excellent paving
sets could be had of the indurated silurian slate at Penman-
maur, in North Wales; and so, forthwith, the importation of
Welsh paving sets began upon a great scale; for, unfortunately,
neither the surveyor nor his corporate masters seem to have
had any notion of the fact that paving sets of equally good
(indeed, in one highly important respect, that of not being
slippery, much better) quality can be had in at least a score of
easily-reached places in Ireland. A happy example this of
bne of the ways by which Ireland is always poor and com-
plaining ; she could not manufacture even the paving-stones
for her capital, but ignorantly and wilfully impoverished
herself by unnecessarily importing them, and paying the
Welshman for giving her, ready made, wThat she had in
abhndance beneath her own soil, and to fit which for use
nothing but the crudest art or labour was required.
Between that date (several years ago) and the present
time acres of this paving have been imported into Dublin,
and a large majority of the streets are now paved with it,
and the granite has disappeared.
The outlay has been enormous, the- taxation great,
and its excessive amount ^continually the subject of pub-
lic complaint. And now, what are the immediate conse-
quences ?
The largest proportion of the passenger traffic of Dublin
is carried on by means of Irish cars and four-wheel cabs, all
with small wheels. The goods traffic is light, and the pace
of,the small Irish draught-horse fast. The result is, that
the streets of Dublin are at this moment probably the noisiest200
ON THE CONSTBUCTION OF THE
of any city in the world. In some narrow streets of greater
traffic, such as Grafton-street, Mary-street, Capel-street, and
Parliament-street, it is, in the daytime, scarcely possible
sometimes to hear one’s own voice at a shouting pitch.
An attempt was made to produce some sort of bottoming for
this Welsh pavement, by spreading a stratum of dry rubbish
(often the most heterogeneous and crude, such as broken or
soft bricks, slaters’ and calp quarry refuse, &c.) mixed with the
screened-out remains of the old road metal beneath; but,
owing partly to this, partly to the frequent ripping up to get
at sewers, water and gas pipes, &c., and partly to the soft
and ill-drained substrate, this paving is already, in very
many places, in a state of great unevenness and disrepair.
And yet the traffic of all sorts in Dublin is of the very
lightest description, and, in proportion to the large acreage
or surface of the 120 miles of streets, is probably the very
smallest of any large town in the United Kingdom.
The annual cost for repair cannot be got at; it is cer-
tainly not small, and if it were added to the interest of the
capital sunk in the pavement, there can be but little doubt that
the annual sum would more than equal what would be suffi-
cient to keep effectually in good repair an equal surface of
Dublin streets, if originally properly Macadamised.
Nothing but this somewhat lengthened sketch of the
history of the streets of Dublin would have enabled it to be
seen distinctly that the lesson which that history teaches is
not that which Sir John F. Burgoyne has deduced from his
own necessarily incomplete knowledge of its circumstances.
The conclusion to which it points is this, and this only :
that bad Macadamising is one of the worst apd most ex-
pensive of roads. But it does not afford the slightest ground
for concluding that good Macadamisation might not have
been practised in Dublin in place of bad, and at a greatly-
diminished cost. Still less is there any warrant for the con*
elusion that Macadamising is an unwise, an unsuitable, or
an expensive mode of forming the surfaces generally of
great cities, or that it is not capable of withstanding, if
properly executed, any amount of traffic.
Experience goes altogether the other way. Derby and
Birmingham, with several other large English towns, are, or
were, admirable examples of the silent, smooth surface that
may be thus maintained under the heaviest traffic.
In Glasgow, Liverpool, Salford, Paris, Rouen, Havre, Bor?
deaux, Marseilles, and many other places, the same lessonSTREET SURFACES IN CITIES.
201
may be learned. In London we have hundreds of streets with
Macadamised surfaces, over which the habitual daily traffic,
both the heavy and slow—and the light, or even, heavy
and fast—is five-fold what ft is in the busiest part of any
street in Dublin, and yet no difficulty is found in maintaining
a sound and good surface. Such, for-'example, are the
Westminster Bridge and Waterloo Bridge Roads, numbers
of the roads at the south side of the Thames, and many at
the north-east of London
A few streets in London are notorious for being always
in bad repair. Sycb is the case with Whitehall, from
Charing Cross down to Parliament-street; but here the fault
is not in the Macadamising, and the traffic is not particularly
heavy. The reason here is a wet and undrained bottom. The
whole of the clay, from the top of Regent-street, as it slopes
down to 'Whitehall, and beyond it to the river, is filled with
land springs ; and if ever a sound and durable Macadamised
surface is to be given to Whitehall, it must be by the adoption
of one of two methods : either the subsoil, for three feet at
least below the crust of the road, must be effectually drained
dry, by French or other cross drains opening into the
main sewers, and at very frequent intervals; or by the happy
method by which the same difficulty has been overcome ir
Regent-street, viz., by laying down, upon a good concrete
foundation, an effective bed of sound, hard, uniformly-brokei
road metal, saturated and bedded in coal-tar asphalt and sand
The traffic, of Regent-street is very large. This asphalti*
Macadamisation has now been laid down several years; it
surface is still and always excellent, and its repairs seen
to be as yet absolutely nil.	Its silence is almost as great a
that of wood pavement, much less than on dry or wet com
mon Macadam, and the Regent-street shopkeepers ar
unanimous in praising its freedom from dust and mud.
One evil there is in ordinary Macadam, where certain sort
of whinstone are employed as the material.
In Glasgow, for example, the dark blue-green whinstone <
the streets is so rich in protoxide compounds of iron, that th
splashes of the black mud produced by it when ground up i
wet weather stain indelibly, and destroy at once both ma
and female clothing of light colours—sometimes altering tl
dye by more or less deoxidation of its colouring matter;
other cases giving rise to a permanent spot of “ iron mould
This is a minute but far from an unimportant evil—01
from which some, but only a few, whinstones are quite fre
k 3202
STREET SURFACES IN CITIES.
It is, however, completely avoided, whatever be the quality
of the stone, by the method of laying in asphalt, in which
every stone is hermetically sealed up.
In extremely wet climates, or in such as vibrate for a
long time in spring and autumn upon the confines above
and below the freezing temperature, Macadamisation, unless
asphalted, does undoubtedly present some disadvantages.
Thus the evil consequences that were inevitably produced
in Dublin by the wretched style in which the Macadamisation
was executed, were aggravated and made more intolerable
by the wetness of the Irish climate, and also by the pecu-
liarity of the traffic. For, small as it is, the effects of the
extremely small diameters of wheels of the Irish “ outside
cars ” are necessarily severe on any roadway ; and, from the
way in which these vehicles (the most barbarous and un-
mechanical of any in the civilised world) are constructed, the
load acts with an increased momentum in producing impact
through the wheel upon the roadway.
Asphaltic Macadamising was employed with perfect
success in Paris long before we introduced it here. It is
destined, without doubt, to be hereafter recognised as
the very best material for the street surfaces of populous
cities, and one that, with only perhaps a single exception as
to condition, may become universal. That condition is
where the whole of the traffic in each direction must be con-
fined constantly to a single and the same narrow track,
owing to the crowding and to the narrowness of the way—
as, for example, on London Bridge. In such a case, nothing
but the very finest and hardest smooth pavement can with-
stand the continuous roll over the same line, and even that
is cut down and ground away before long.
The only cases in which a doubtful choice may lie are
such as in Liverpool, certain parts of Manchester, or about
any of our great docks, where the whole nearly of the traffic
is slow and very ponderous, and where, notwithstanding its
other and many disadvantages, pavement, laid with open
gravel and asphalt-filled joints, is probably less expensive
to keep in repair than any other known surface.
The preceding note was written in 1865, or nearly four
years ago. Since that time it is but just to those concerned
to say that considerable improvement in the practice of
repairing and laying the streets of Dublin has, it is said,
taken place. The nuisance of paving has, however, been
effected, and cannot, or is at least not likely to be, undone.
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