oe anon 
62 
The greatest difficulty a road-maker has to 
contend with is a bad substratum or natural 
soil. If that is good and hard, and so situated 
that it can be drained, a good road may always 
be formed, especially if good gravel or other suf- 
ficiently hard material can be found to cover it. 
In clay countries, where gravel or stone of any 
kind is scarce, an artificial material may be formed 
(if wood abounds), by making the clay into balls 
and burning them until they are nearly vitrified. 
On the same principle, the slag or refuse from 
iron and other furnaces, makes an excellent ma- 
terial. In the neighbourhood of collieries, the 
stony or slaty part of coal is used, and in the 
south-west part of England many of the roads are 
formed wholly of hard or stone-chalk. In fact 
almost any thing, except sand, will make a tol- 
erable road, if kept dry, properly scraped, 
cleansed and attended to, and the substratum 
is hard, dry, and absorbent. Hardness alone is 
not sufficient, for solid and compact rock is a 
very bad bottom, unless when covered by so 
thick a stratum of good material, as will prevent 
the surface water from sinking down to it, or 
its irregularities from being perceived. Rocky 
countries are generally very broken and hilly, and 
owing to the smooth surfaces presented, and the 
water being unable to penetrate into them, the 
materials will not adhere and become fixed, but 
are very liable to be washed away by the floods 
of rain, so frequent in such places. A sandy 
substratum is also difficult to conquer, except 
by such a thickness of gravel or broken stone as 
will entirely prevent any concussion or vibration 
that occurs at the top from being transmitted 
below. Should it take place, the lower stones 
will sink gradually into the sand, which will rise 
and mix with the upper stratum, thus making 
room for that to descend until the whole may be 
lost or buried. The most effectual method of 
counteracting this effect is to dig the sand out 
to about a foot in depth, and to place large and 
flat stones upon the bottom, so that they may 
take an extended bearing upon the sand; to fill 
in with large broken stones, or old brick rubbish, 
if it can be procured, and to finish with stones 
broken to the usual size. The worst bottom, 
however, that has to be contended with, is a 
bog-swamp or morass, in which the ground is 
soft and full of water, so as to be incapable of 
supporting small stones, and from which no 
drainage of the road-way can be obtained. IJt 
frequently happens on inspecting a situation, 
even like this, that some outlet may be found 
for draining off the top water of a morass, though, 
perhaps, only for a foot or two, and yet this will 
at times render the surface better, though it will 
generally sink or become lower when the water 
is drawn away from it. It is, however, advisable 
to drain it as far as possible, and that done, there 
is no better way of forming a road-way than by 
placing fascines (as they are called in the lan- 
guage of military engineering), or bundles of 
an ea i ALP Se 
ROCAMBOLE. 
brushwood tied together and disposed regularly 
by the side of each other in the manner of pav- 
ing, and then placing a second course above 
these, laid in the cross or opposite direction; 
the next, or third course, should be parallel to, 
and in the same direction as the first. The num- 
ber of layers or courses of these fascines will, of 
course, depend on the nature of the place, and 
the quantity of sinking or depression that will 
take place when they are loaded with gravel. 
Should the place be very bad, two or three 
courses may be laid, and then covered with 
small poles or young trees, laid across the in- 
tended road-way (in the manner practised in 
America in wet and soft places), when other 
courses of fascines or faggots should be laid upon 
them ; the only use of the poles being to bind the 
whole together, and prevent the possibility of 
one part sinking without another, thus extend- 
ing the pressure over a considerable quantity of 
surface. The platform of fascines, being thus 
formed, should be covered with large and flat 
stones if they can be procured, and a thin stra- 
tum of loam or clay, that is nearly impervious 
to water, is sometimes laid over them, after 
which the road is gravelled or covered with 
stone, in the usual manner. The weight of the 
road materials will generally cause the fascines 
to sink in the soft bottom until they disappear, 
and sometimes even the whole road may sink to 
such an extent as to become useless; and the 
only way of recovering it is to repeat the former 
process until a good and hard road is obtained. 
This is a very expensive mode of proceeding, 
and one which, of course, would never be adopted, 
except when local circumstances render it abso: 
lutely necessary; because, in most instances, it 
would be better, and probably, cheaper to go a 
few miles round, than to cross directly over a 
bog or morass. See the article Pavine. 
ROAD-SCRAPINGS. The mud raked and 
shovelled from carriage roads. It varies exceed- 
ingly in composition, according to the nature of 
the stones or gravel or other stuff of which the 
roads are made, and to the amount of animal 
excrement which is dropped upon them; but, in 
every case, it possesses considerable manurial 
powers, and is a good material for forming com- 
posts, particularly to clay lands. See the article 
Compost. 
ROAN-TREE. See Asn (Mountarn). 
ROARING. A disease in horses, who, in con- 
sequence of it, are popularly called roarers. See 
the article Broxun-WInD. 
ROAST-BEEF PLANT. See Iris, 
ROBIN. See Reppreast. 
ROBINIA. See Acacta-Tree. 
ROCAMBOLE,—botanically Allium Scorodo- 
prasum. A hardy, bulbous-rooted, culinary plant, 
of the garlic genus. It is used in salads, and as 
a pot-herb, and is sometimes called Spanish gar- 
lic, but is milder than common garlic. It was: 
introduced to Britain from Denmark toward the 
