have.accordingly been Completely rejected. 9 6) > 
¥ Fectibe ceaemeation tot. demi-lunes,. some have gi 
them their defence from the curtain, as ADC, Fig. 2. 
where EF, GH are from 48 to 60 feet, and the faces of 
= 
Prate 
 CCLVET. the ravelin 130 to 180. Others have taken the defence 
Fig. 2. from the orillons,as IDK, where the faces are from; 200 
to 230 feet. Sometimes also they have been construct- 
ed in the form LDM ; but all forms are inferior 
to what will be described afterwards. - ut 
Demi-lunes are surrounded in the same way as the 
enceinte, with a ditch and covered way, the former be- 
ing from 48 to 60 feet wide. 
Fausse- . A second enceinte, called the fausse-brave, has some- 
brave. i 
above, has undergone many changes, and received con- 
siderable improvements since the time of Errard. Of 
BEF 
He 
: 
1 the side. 
t to the line of defence, 
orillons, w are curved outwards, one third 
RESLPE 
PtepeeR 
ae 
re 4 
FE 
ae 
: 
possesses consi- 
over the method adopted by Pa- 
gan. sharon aa to local. circum. 
stances, as parts diminish with the side and angle 
of the The flanks have an advantageous po- 
baations are more spacious, 
VOL, IX. PART U. ; 
if 
FORTIFICATION. 
489 
» Vauban also!inttoduced a change in the construction Permanens 
- —— pb ok earth veined above the rest = 
‘the fortification, for the purpose, of! commanding a , : 
distant part of the field.’ Formerly these had been jy the in- 
placed in the curtain and various other parts of the for-, vention of 
tification, and were sometimes used for defending the cavalicrs. 
ditch. In these positions, however, they were found 
to embarrass the manoeuvres of the soldiers. Vauban, 
therefore, enlarged their size, and placed them in the 
bastions, whence they could more effectually. defend 
the curtain. They are traced thus; A parallel 36 feet 
from the interior of the t, denotes the exterior 
side of the talud or slope of the escarpe, and 18 or 20 
feet farther back, is drawn the fire-line or interior side 
of the cavalier, In small bastions, the talud is almost 
perpendicular, and the earth is prevented from falling 
down by a revetement. This revetement, however, 
ought in no case to be higher than the parapet of the 
bastion, that it may — ie o pect a 
the garrison may not be inj y the splinters. It is 
also a dianclviicbgae attending cavaliers of this. kind, 
that they ent the bastion from being intrenched 
farther . Nor is this defect remedied by carrying 
a as some engi have done, from the ca- 
valier to the bastion, and constructing a ditch before 
ba ey Aang iF am acorn as soon as a breach is 
made. A more advantageous method of constructing ca- 
valiers will be given in a subsequent part of this article. 
The improvements which Vauban introduced, were jn outworj:s, 
not confined to the enceinte alone. He also maie se~ 
veral advantageous alterations in the construction of 
outworks, though, it must be admitted, that he left not 
a little to be done in this way by his successor Carmon- 
taigne. The first outwork used by Vauban, is the te- 
naille aC t, Fig. 3. It is placed before the curtain, yention of 
and by a ditch sufficiently large to receive tenailles. 
the earth that may fall from the curtain, and which Prate 
might otherwise fill the terre-plein. Of course it, in a mah 
get entend on the use of the fausse braye, "8 > 
n his first illes, Vauban used flanks, as be, gf, 
th they were afterwards omitted. In constructing 
tenailles of this kind, h7, ef are parallel to the curtain, 
the first at 16, and the last at 60 feet distance ; a k, tl, 
30 feet from the flanks of the bastion ; a b, tg, equal to 
one-half of aC or ¢C ; and the flanks 6 ¢,¢/; parallel to 
those of the bastion. Having determined a 6 e, and tg f, 
in the in- 
pra ee emer St per and. at the distance of 
54 feet, akh 7 li for the interior side of the terre- 
plein. Thus the terre-plein of the faces and flanks of 
the tenaille is $0 feet, but that of the curtain only 18, 
In constructing tenailles without flanks, which are - 
found to be most advan’ » the flanks being easily 
destroyed, the faces a 4 and t g are continued till they 
meet opposite the centre of the curtain. By this form, 
the tenaille is not enfiladed, and the besieged may re- . 
tain it even after the fossé is taken. The form. would 
be still farther improved, if, instead-of forming an angle 
aC t, it were parallel to the curtain. It would thus af. 
ford a direct fire on the terre-plein of the ravelin, and 
a the ditch to be made larger. 
e tenaille answers several important purposes, It 
covers the sally ports of the curtain and flanks, by which of the tc. 
the besieged communicate with the ditch ; preserves a naille. 
communication with the ravelin, and secures the re- 
treat of those who defend it; protects the men in the 
fossé when dry, and the boats whem wet; affords a ra- 
zing fire on the enemy whem crossing the ditch, and 
covers the revetement of the curtain to a-certain height. 
Itis also of great usein case of a breach being attempt- 
30 
Advantages 
