Commas 
for 
erie facie baw The following were given 
Errard : 
Ist, That the saliant of the bastion should ne- 
ver be less than 60°, pag! s! rere ry. hen practicable. 
2d, Tiss, « Baska ae should be 
within musket ee meee viz. from 700 to 
90 he 
Sth, That all the works of a fortification ought to be 
ye oa in elevation, that the one nearer the 
place I be higher than the one before it. 
Notwithstanding the excellence of these rules, how- 
ever, the frace of was very defective. He left 
all the lines to be determined by the constructor ; the 
ee ats a ehegelst greubt, ous dca to be 
" on 1 was cult to tra- 
Tt was also too small, and rendered less eas cosy. fo 
be defended, from being icular to the face. 
i i these faults, by deter- 
the various with more precision, and on 
more accurate principles. The improvements which 
fallowed, were adopted partly in one country, and part. 
ve rise to the different me- 
in another, and pa 
Luni ees rench, Italian, Spanish, and 
Dutch. sl Bod, however, may be considered 
as essentially the same, the difference among them be- 
ing chiefl mn the saliant angle of the bastion, and the 
form of the flan 
Whatever pan of fortification be adopted, it is of 
im to observe, that all the works ought to be 
traced out in the exterior poly, If they are traced 
on the interior, the different one ig ke cae be ger 
mined with the same accuracy Se tige, Spire gs 
we proceed to lay down the Pathe vie toc most plied 
Sits pore of Gee aioe deaty 
The of the bastion should never be less than 
from 160'to 200 feet wide, so as to afford a free com- 
munication with the bastion, and room for meunting 
two or three guns. 
The length of the flank depends on the } of the 
line of defence, and what it is required to defend ; but 
it ou: t never to be Jess than from 180 to 200 feet, 
anid id be perpenticiiie to the thon which it be. 
tended to flank. 
The orillon should never be larger than to allow two 
ee Sech ame 2 be Pleeed pe fhe aoreced Pash, If it 
be more, it weakens the flank. 
To increase the offensi er of the flanks, 
have sometimes been p in vaults cut out of the 
rampart beneath, These vaults are called casemates ; 
but they have been objected to on account of their di« 
minishing the strength of the flank, their annoying the 
gunners with smoke, and To 
lensive 
orillons. In Sect ia elena ean be a foe 
pet, and the ammunition DB ages in a vault Lea, 
—- of the higher Compared with case- 
lower flanks are undoubtedly an improve- 
at the same time, they’ certainly diminish, 
degree, the effect of the higher flank ; 
FORTIRPICATION. 
and it may choesfernhedevinappwiennk: hov:ie far they: 
are, in many 
The saliant of mange ap as 
less than 80. and if it could be made to exceed. ~ 
90, it would ein arenes nae any mH 
Vv 
ston. The dunked age woul 
enlarged, on 
te toe eee se rar gh ata - 
greater distance from one 
The } of the faces is determined by 7y that of the. 
curtain and the side of the po polngie tv eg reenloy 
ought it to be more than $50; 230 feet. 
The curtain should never exceed 500 fet 
short. of 200, 
The depth of the ditch or fossé generally 
on the nature of the ground, th quant of ar 
wanhat in tec dente | res a be de-. 
niet ie circumstances, but t never to exceed. 
100 or 180 feet. The ditch always to be dry. 
we there are no ger paca es 
e covert way is can ee eae ene- Covert . 
my from approaching too near the ditch iyi 
them to be more. watchful in arding Seis wee 
while, at the same time, it les the 
more easily to defend their outworks, as well as 
lect their troops in safety when they intend to 
a sally. The covert way is pees oe 
of the ditch, and varies in breadth: 
according to circumstances, In all cases, 
of such a width as to allow (ren 
manceuyre without: 
fending it, In order to. give 
cation a complete pay ored of the 
which the plane of the latter males ie 
ought to be such, that if the eae 
would pass through the highest part bot! 
wethe epace A’ in the’ be sl Lense i 
space A’ in the re-entering | 
way, is, called a place of arms, ef which 
lines focaing: the saliant ne eh ate 
in length, in the salian 
covered way ae yee 
places were ound to -great use i 
covered way, but were soon rendered 
them with a ditch toon th 
vered way, and on the escarpe of that ditch construct 
ing a rampart for the defence of the»men within. 
this form, Phe sock in callethentioasyaanaier peer 
ADCB, Fig, 2. The ori A teepires of the demi-1 
In, taken. B ‘enlargin, ees 
ing * Senne to <2 more patensinely useful. 
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cman » ng, glacis, vata prevent. the eretion of 
wor in two positions very v ‘or 
won ov antageons fo attacking 
an f sigs 
Some engineers have erred” 
lunes before the a better » from 
affording, 
the works. constru the ¢ 
the faces. and flanks. oie 
ble to several objections. 
tains, and even the 
munication with the 
