FORTIFICATION. 
to a heavy cross fire. The ravelines, them- 
selves, stand at too wide an angle to ab- 
solutely flank each other, but they are ca- 
pable of scouring the glacis reciprocally, 
and would, as before remarked, subject the 
besieger to a dangerous enfilade, or flank- 
ing fire, were he to proceed without due 
attention to their obnoxious positions. In 
works of more sides, where the angles of 
the bastions are necessarily more obtuse, 
the ravelines are thrown more towards a 
right angle with each other, and afford mu- 
tual support, even in cases of assault. 
The communications with the ravelines 
are effected by the aid of bridges, when 
wet ditches are in question, as may be seen 
in the third face, y z, where the bridge V 
is carried over from the curtain to the 
counterscarp, or outer face of the ditch, so 
as to afford access to the raveline K, in 
which is the intrenched redoubt L. The 
double lines T, represent a channel of 
about 14 feet broad, and about 6 or 7 feet 
deep, made in all ditches that are at any 
time filled with water. These channels are 
called cunettes, or cuvettes ; they are 
usually lined with masonry, and kept full, 
so as to prevent a surprise : when the water 
is allowed to fill the whole of the ditch, 
which should generally be to the depth of 
9 or 10 feet, or at all events so as not to 
be fordable, the cunette proves a formida- 
ble obstacle. 
The bridges have barriers at their outer 
ends, and towards their inner ends gene- 
rally a drawbridge, besides one that lifts 
immediately under the gateway, to which 
it gives additional strength. The very 
small compass allowed for the exhibiting 
of such figures as are indispensably neces- 
sary towards the right understanding of 
the subject, absolutely precludes the pos- 
sibility of shewing the dimensions of the 
ramparts, &c. and occasions the omission 
of many particulars in the plate, which 
must be therefore' described. The fore- 
going impediment prevents us from shewing 
the berm, which is a space, always left, 
between the cordon that runs along the 
inner brink, or scarp of the ditch, and the 
foot of the ramparts. Its use is to prevent 
the latter, when battered, from falling into 
the ditch; and it affords likewise a very 
good line of communication all around the 
works. The breadth of the berm is very 
uncertain ; it should never be less than six 
feet, even where the works are scarp’d from 
the solid rock, and not subject to let fall 
much rubbish when battered. In the com- 
mon mode of building ramparts with a re- 
vetement of masonry, the berm should be 
at least 10 or 12 feet; and where only 
turf facing is used, or that the soil with 
which the rampart is filled, between the 
outer and inner faces of masonry, is of a 
loose nature, the berm should then be full 
20 feet broad. The bulk of the rampart 
should, however, be considered, also whe- 
ther it be much exposed or not ; for on 
these points much will depend as to the 
probable quantity of battered rubbish to be 
sustained. There used, to be a work, 
called the fausse-braye, carried all round 
the principal and the edge of the berm ; 
its intention was to defend the ditch, and 
its fire was indeed highly destructive ; but 
the facility with which it could be enfi- 
laded, for it was necessarily low, evinced 
its inutility in general : the immense num- 
ber of splinters falling from the rampart, 
immediately above, was another formida- 
ble objection. The fausse-braye is, there- 
fore, out of repute ; though in some forti- 
fications, a substantial parapet supplies its 
place, generally of masonry, more for the 
purpose of stopping the rubbish of a bat- 
tered rampart, than for the means of shel- 
tering troops. Perhaps the strong hedge, 
adopted in many instances, may be prefer- 
able ; to say the least, it is far cheaper, 
and stands to more advantage on the berm, 
than a heavy range qf masonry. 
The first draw-bridge generally connects 
with the body of the bridge passing over 
the ditch, and is drawn up by persons 
standing on the berm ; while that draw- 
bridge, which rises close np against the 
gate, is so contrived as to bury itself, for at 
least its whole thickness, into the masonry ; 
whereby its edges are secured from the 
grazing of shots, ranging against the wqjl, 
and the possibility of wrenching the draw- 
bridge out of its place, is sufficiently ob- 
viated. The gates usually close in the or- 
dinary way of all large ones, i. e. in two 
leaves, meeting in the centre ; over them a 
portcullis is sometimes suspended horizon- 
tally ; its hinges being close behind the 
gates when shut. This immense machine 
resembles a very large harrow, and lets 
down, much like the ports of a ship, until 
it hangs vertically, close at the back of the 
gates, and being secured with long iron stays, 
beams of wood, passing like window bars 
into the wall and other devices, it proves 
adequate to the repulsion of even a com- 
mon sized petard. Some places have a 
succession of such gates and portcullises one 
