FORTIFICATION. 
works beyond its ditch may be very nume- 
rous, though not so varied as those placed 
beyond a crown- work. 
The object of both these defences, gene- 
rally, is much the same ; when a small di- 
minishing tract is to be covered, the horn- 
work is proper, but when a round, or rather 
encreasing spot is to be enclosed, the crown- 
work should be preferred. The intreneh- 
ments within a horn-work are, however, 
the strongest, because they oppose a larger 
front agaiust a smaller one ; which is the 
reverse of what takes place in the crown- 
work, where the intrenchments / /, are 
narrower than the front, which can be op- 
posed to them between the flanked angles 
of the demi-bastions b b. 
Tiie explanation of fig. 2, next demands 
onr attention : it is the profile of the prin- 
cipal, and of the proximate outwork. In 
this, not only the defilement, but the de- 
viations from the terre-pleine, or line of the 
horizon, whether by superstructure or by 
excavation are shewn. 
A, represents the rampart of the principal, 
or body of the places of which the measure- 
ments may be in general terms taken at 
the following computation. The height of 
the terre-pleine H, on which the cannon are 
mounted, 20 feet; the banquette I, on 
which the soldiers stand to fire their small 
arms, raised 3 feet above H ; the point X, 
which is the crest of the parapet, being 
4 i feet above the banquette I, and 7 1 above 
the terre-pleine, H. The upper part of the 
parapet is lower without than it is at the 
crest X. This declination, which is called 
the superior slope, is at the rate of one inch 
for every foot the parapet has of thickness, 
so as to allow the defenders to fire at an 
enemy almost close to the rampart, yet not 
to weaken the crest. K, shews a revete- 
ment of masonry, which should be five feet 
thick at the top of the rampart, not includ- 
ing the parapet, but measuring at the up- 
per cordon O. The exterior slope of the 
revetement should be one sixth of its height, 
taken from the foot to the cordon. The 
foundation should project in proportion to 
the height, and to the nature of the soil. 
The interior slope of the parapet, and the 
banquette, are likewise bounded by a re- 
vetement in this figure, but such is not 
always the case, when it is, the ascent to 
the banquette is made by two or three 
steps, as here shewn. Nor are all parapets 
faced with masonry ; the generality, indeed, 
are gazoned, or turfed, on account of the 
incalculable injury done by the splinters, 
knocked off by such shots as graze upon 
masonry of any kind. In some instances, 
only half revetements are used, that is, only 
for the scarp, or face of the ditch, as seen 
at M under the cordon O ; the whole ex- 
terior of the rampart itself being gazoned. 
The interior slope of the rampart, when 
made of masonry, as seen at P, where the 
counterscarp is carried up, or built upon, 
to form the interior slope of the counter- 
guard B, may be equal to only one-fifth of 
its whole height ; but where masonry is not 
used, the interior slope, as at L, of the ram- 
part A, should, if the soil be firm, be equal 
to the height of the rampart, which would 
give an angle of 45 degrees ; when the soil 
is sandy, crumbly, or apt to give way, the 
interior slope should be equal to a height 
and a half, or even more, if circumstances 
should require. The continuation of the 
revetement M, above the cordon O, which is 
level with the terre-pleine of the berm N, 
is a firm parapet, made in lieu of the ex- 
ploded fausse-braye, to prevent the ruins 
of the rampart A, when breached, from 
falling into the ditch C ; of which the 
breadth is indefinite, though from 15 to 25 
toises may be considered as the limits for 
works according to the mean, and great 
systems of Vauban. About the middle of 
the ditch, but generally rather more to- 
wards the counterscarp P, than towards 
the scarp M, is the cunette, or cuvette, 
about 15 feet broad, reveted throughout, 
and from six to nine feet deep. It is always 
kept full of water, where that may be prac- 
ticable ; and as it goes entirely around the 
body of the place, serves to prevent a sur- 
prise, to restrain from desertion, also from 
an improper access to spiritous liquors, and 
as a drain to the body of the ditch. In 
many instances, very fine supplies of fish 
are obtained from the cuvette. In some 
fortresses it is cut off from before the cur- 
tains by rows of pallisades, standing on a 
shelving work, called a batardeau. Where 
it is continued before the curtains, there 
must be bridges of communication; and 
small temporary plank passages are made 
over in various parts, when occasion may 
require. All ditches should be sown with 
good grasses, that they may give a supply 
of that valuable commodity to such horses, 
&c. as may be kept in the fortress ; and all 
gazoned facings, as well as the slopes of 
parapets, should be regularly mown for the 
same purpose. 
The counterguard B is solid, as is also 
the rampart A ; its terre-pleine H is consi- 
