130 K Q 
Mr. M'Adam’s method is the introduction of a greater 
proportion of human labour, instead of the work of horses: 
formerly one-fourth of the whole expense was paid, in the 
district of Bristol, for men’s labour, and three-fourths for 
that of horses: now, on the contrary, one-fourth only is 
paid for horses’labour, and the other three to men, women, 
and children. 
Mr. M‘Adam argues very strongly against the old opinion 
of the necessity of placing a quantity of large stones, as a 
foundation, to carry the road over a wet subsoil. He says, 
that'whatever be the nature of the soil, if it be previously 
“ made quite dry,” and a covering impenetrable to rain 
placed over it, the thickness of the covering needs only to 
depend on its own capability of becoming impervious. 
Large stones, he says, will, constantly work up by the agi¬ 
tation of the traffic on the road, and leave vacuities for the 
reception of water; and the only way of keeping the stones in 
their places* is to have them of a uniform size. A rocky 
bottom causes a road to wear out much the faster [acting, 
probably, as a lower millstone in facilitating the operation of 
grinding]. “ It is a known fact, that a road lasts much lon¬ 
ger over a morass, than when made over rock. In the neigh¬ 
bourhood of Bridgewater, for example, the materials con¬ 
sumed on a rocky road, when compared with those which are 
required for a similar road made over the naked surface of the 
soil, are in proportion of seven to five.” 
In the summer of 1819, upon somenew roads made in Scot¬ 
land, more than three feet of materials, of various dimensions, 
were laid down; and more than two-thirds of them, accord¬ 
ing to our author, were worse than wasted. In such an 
arrangement, the water generally penetrates to the bottom of 
the trench made to receive the road, and remains there to do 
mischief upon every change of weather. 
To prevent such inconveniences, it is necessary in wet- 
soils, either to make drains, to lower ground, or to raise the 
road above the general level, instead of making a trench to 
receive the stones; and from the penetration of rain the solidity 
of the road itself must protect it. A well-made road, not 
quite four inches in thickness, was found to have kept the 
earth below it dry in the parish of Ashton near Bristol: but 
six, eight, or ten inches of materials are generally required to 
make a firm road, being laid on in successive layers of about 
two inches in thickness, all well broken, well cleaned, and 
well sized. Sometimes, indeed, a much greater depth of 
stone than this is required: in a road, for example, which 
was made from Lewes to East Bourn, entirely upon Mr. 
M'Adam’s principles, as much as three feet of materials was 
required in many parts before the road could be sufficiently 
consolidated; it has however, ultimately, been made excellent, 
though at an expense of not much less than a thousand 
pounds a mile. 
Mr. M‘Adam maintains that the quantity of stone required 
for paving is fully sufficient to make an excellent gravel road 
in any part of the world; and in almost every case, materials 
equally good can be obtained for roads at a still cheaper rate; 
commonly, indeed, atone-tenth of the expense of pavements. 
It is, however, in steep ascents that pavements are, most objec¬ 
tionable. At the north end ofBlackfriars Bridge, previous to 
the taking up of the pavement, more horses are said to have 
fallen and received injury than at any other place in the king¬ 
dom $ and frequent accidents of the same kind occur at present 
on Holborn Hill. Otherwise Mr. M‘Adam f s plan seems far- 
more conducive to the comfort of quadrupeds thanbipeds. In 
all those places where it has been tried on flat surfaces, and roads 
of much traffic, the mud has been found to accumulate 
exceedingly fast in wet weather; while in the summer season 
almost continual watering has been required to keep down the 
dust. These, it must be confessed, are minor inconveniences, 
and may probably be made to disappear by some further 
improvements. 
II. Of Rail-Roads. 
A rail-road isa contrivance whereby the surfaces of wheels are 
secured from devious course, and are relieved from the friction 
of irregular ruts, stones, &c. It may either be formed into a 
A D. 
perfect level, or it may have such a gentle fall as will facrl itate 
(in one direction) the passage of loads placed upon it. From 
tire accuracy with which its resistance may be calculated, it is 
very proper for steam-engines or other mechanical locomotive 
powers, but it is of incalculable benefit even to draught 
horses. 
In the construction of the iron rails, two very different 
plans have been adopted. The first.- is termed the flat 
rail, or tram-road ; the rails being lain on their side 
and the waggon-wheels travelling over their broad and 
flat.surface. The second is termed the edge-rail; the rail 
being laid edgeways, and the wheels rolling on its upper 
surface. The fiat rail, or tram-plate, consists of a plate of 
cast-iron, about three feet long, from three to five inches 
broad, and from half an inch to an inch thick; extending 
from sleeper to sleeper, and having a flaunche turn up or 
crest on the inside, from two and a half to four inches high. 
This rail bears on the sleepers at each end at least three 
inches, where the rails are cast about half an inch thicker, 
than in the middle. As there is no intermediate bearing for 
the rail between tire sleepers, except the surface of the road, 
the use of the flaunche is not merely to prevent the waggon 
from being drawn off the road; it resists the transverse strain 
arising from the weight of the waggon : on this account it 
is often, and with great propriety, raised higher in the middle 
than at the sides, forming an arch of a circle; and, to 
strengthen the rail still farther, a similar flaunche, arched 
inversely, is added below, as represented in the annexed Plate, 
figs. 1, 2, 3. The weight of each rail is from forty to fifty 
pounds. To unite these rails into one continued line, they 
are merely laid to each other, end to end, all along each side 
of the road; being kept in their places, and at the same time 
made fast to the sleepers, by an iron spike driven through the 
extremity of each rail into a plug of oak fitted into a hole in 
the centre of each sleeper. This spike is about six inches 
long; it has no head, but the upper end of it forms an 
oblong square, about one inch broad, half an inch thick; and 
the hole in the rails, through which it passes, is formed by a 
rectangular notch, half an inch square, in the middle of the 
extremity of each rail; the opposite notches of each rail- 
forming, when laid together, the complete oblong square of 
one inch by half an inch and slightly dove tailed from top 
to bottom, so as to fit exactly the tapering head of the spike* 
which is driven clear below the upper surface of the rail., 
Fig. 4, represents a section of a rail, with its sleeper and 
fastening. Wherever the rails cross any road, the space 
between them and on each side must be paved or cause¬ 
wayed to the level of the top of the flaunches, that the car¬ 
riages on the road may be enabled to pass clear over the 
rails. In single railways it is necessary to have places at 
certain intervals where the empty waggons, in returning, 
may get off the road to allow the loaded ones to pass. A 
place of this kind is termed a turn-out; and the waggons are 
directed into it by a movement rail termed a pointer, fixed 
at the inlersectiou between the principal rail and the turn¬ 
out, and turning on its extremity, so as to open the wav into 
the turn-out, and shut that along the road. This contrivance 
is also used whenever one line of railway crosses another. It 
is represented at the annexed Plate, fig. 5, where, also, fig. 6 is 
a plan of the railway and of the turn-out. 
The tram-roads have been universally adopted in Wales 
where they are preferred to any other species. They are 
also used in most parts of England. The Surrey railway is 
of this description, and was designed by Mr. Jessop. In 
Scotland the Duke of Portland’s railway, which, we believe 
was planned by the same engineer, is of the same kind, and 
the rails nearly of the same dimensions. These flat railways 
have one advantage, in admitting waggons or carts of the 
ordinary construction, and this is particularly exemplified 
in the Troon railway. According to an account which 
Iras been given by Mr. Wilson, of Troon, “ there are 
several kinds of waggons used upon the railway under 
certain restrictions ; such as four-wheeled waggons with flat 
bottom and lowshelmets for carrying stone, limestone, grain, 
timber, slates, &c. from the harbour to Kilmarnock, the 
mills. 
