FORTIFICATION. 
behind the other, which added to the case- 
mates being lined with defenders, renders 
it almost impossible to force these passsages. 
When matters are driven to extremity, 
owing to the raveline being possessed by 
the enemy, and by the defences on the 
curtain and flanks being rased, the gate- 
ways are then filled up with rubbish, either 
loose or in bags, &c. so that they are no 
longer passable. 
The nakedness opposite the angle B, of 
bastion 3, is left purposely to shew how 
easily a besieging army would effect a 
break at that angle, provided no additional 
outworks were supplied ; for, as yet, we 
are to consider the fortress to consist only 
of the principal and the ravelines. A suit- 
able train of battering cannon brought to 
act upon the point B, while other batteries 
were employed to silence the faces of the 
adjacent ravelines O and N, would, in a 
very few days, effect a breach, and give 
the besiegers a command of the ditch, by 
establishing themselves in a lodgment on 
the crest of the glacis g, at the saliant 
point q; whence they would batter the 
flanks o S, and w v. Then, as nothing could 
oppose their passage over the ditch, which 
if wet would be passed by sap, (i. e. by 
filling up with fascines, &e.) the angle B 
would be carried by storm : for the matter 
would obviously rest on the numbers, and 
on the personal prowess of the contending 
forces. The issue of such affairs have been 
so various, that it would be presumption 
to say the besiegers must succeed ; but if 
the breach be practicable, and the internal 
state of the bastion, as seen in No. 3, even 
though there should be an intrenchment of 
the gorge, i. e. from r to it, the chances 
would be in their favour, after the breach 
were gained. This mode of defence is per- 
haps the best, in hollow bastions ; that is, in 
such as are not solid, but have deep areas 
within them, level with the streets of the 
town, &c. (called the terre-pleine ;) but in 
a solid bastion, some defences should be 
internally constructed while the breach is 
making ; of this some idea may be formed 
by the flanked angle in bastion 4, where a 
rampart and ditch are made, to force those 
who may ascend the breach to quit the 
bastion. The gorge may also be fortified 
as in bastion 3, whereby much time may be 
gained, a matter often of the utmost im- 
portance, either from the expectation of 
succours, or to favour the evacuation of the 
fortress altogether. 
In bastions No. 3 and 4, the flanks t u, 
and tv v, are not only curved, but they are 
double, presenting, of course, two tiers of 
cannon, of which the upper stand on the 
bastion, while the lower are just below the 
level of file berm, whereof they constitute 
a part, and cannot be discovered beyond 
the crest of the glacis. These latter, 
therefore, cannot be battered from the ap- 
proaches in the early stages of a siege ; 
they lay, as it were perdue, in reserve for 
the defence of the ditch. There are two 
little semi-circular projections at t and w , 
called orillons ; these serve, not only to 
cover the flanks t u and tv v from enfilade, 
but each mounts a gun which cannot be 
perceived until halfway over the bridge, and 
which serve to defend the gate when as- 
saulted, as well as to take the assailants in 
flank, and partly in reverse, (i. e. from be- 
hind,) as they advance to the attack. 
They are especially useful when a tenaille, 
as seen at P, is constructed in the dry ditch 
before the curtain S r ; for when those who 
were placed in the tenailles, which com- 
mand the interior of the raveline O, and of 
the redoubt Q may be attacked in flank, 
and be obliged to retreat into the principal, 
along the caponnaire P A, these guns pour 
in grape along the interior of the tenaille, 
when it is in the hands of the enemy, and 
enfilade so as to cause its abandonment. 
The caponnaire is a passage made be- 
tween two parapets, each having a long 
talus, or slope, outwards ; as expressed by 
the small lines diverging from the path. 
It is commanded by (i. e. open to the 
fire) the flanks o s, and s r, and the centre 
of the curtain sr. Demi-caponnaires are 
common for the passage of troops from one 
outwork to another, as seen at e e, in the 
raveline N, where they serve to shelter the 
narrow defiles leading into the intrench- 
ments fj) within the crown-work M. They 
have but one parapet which is open to the 
fire of the faces B t, and w c, also to the 
oblique fire of the curtain between u and v. 
By their exterior slope they serve to flank 
the passage of the ditch of the raveline, in 
conjunction with the faces B t, and C w, 
which fire over them, and command the 
whole interior of the liorn-work M. 
Having established, by this exposition, 
the absolute necessity for adding exteriorly 
to the defence of the principal, we shall 
now proceed to give a general insight into 
the various modes of constructing the other 
outworks ; all being so designated which da 
not come within the principal, or body of 
the place. The reader should understand, 
