1000000030

590 / 1042

F o R T F
f,onls ~IN, or rather perpendicular to Ihe fide Nq, anel
hife~ the fide qN; Ihe elileh before this rmenehment is
3 loiles, ,nd Ihere is a banquctte bdore Ihe pOTaret
next 10 the oileh of abollt 8 feel, eallecl []rrlll ; il ferves
to prevenl the earth of the p""pel (whieh fclclom has
any revetemenl) from falling imo Ihe dileh.
11 is 10 be obfen'd, Ihal Ihe ravelin, b,forc whieh
teoaillons are eonllruéled, mull harc ils falianl angle
mueh gre'Ier Ihan Ihe former eonflrullion m,kes Ihem ;
othelwife Ihe fdliant angles of Ihe Icnailluns beeome 100
aeute; for whieh reafon IVe made the capital of this ra–
TellO 45 lOifes, and the faces terminate wllhio 3lOifes of
the fllOuloers.
6. ConJIrufli•• of C,u.I,~~ ¡.
Fig. 10. 11 . Whco the eoumerguard is plaeeel before
the tavehn, fel off 40 loires on Ihe "pilal of Ihe ral·elin
{rom Ihe fAlianl angle A. 10 the ["li..lI angle Il, of Ihe
counlerguad; aoo 10 from C 10 D, on the eounterfcarp
of the ditch.
When Ihe eounterguard is before Ihe baflion, fueh as
in fig. 2, its falianl anglc F is 50 loifes from the faliant
anglc E of the baflion, .nd tilO breaUIh near the diteh of
the raveJin is 10 loifes as before.
The dileh before the eounterguards is 12 toifes, and
ils eounlcrfearp pmllel to Ihe faces.
Counterguards are made before the ra.eJin in fome
particular oeeafions only, but are frequendy conllruéled
before 'the baflions, as covering Ihe flanks IVonderfully
\Vell. Some authors, as Blondel, and Mr Cochoro, will
h3ve Ihem mueh narrower Ihan they are here.
7. ConJIrufliM o[ H".'W"l¡,
Fig. 12. Produce the capital of Ihe ravelin beyond
the faliant angle A, at a dillanee AB of aboul 80 loifes;
draw DBE al righl anglcs 10 AB; io IVhieh take BD,
RE, eaeh equal tO 55 toifes; and on the exterior lide
DE, Iraee a froot of a polygon in Ihe fame manner as
that of Ihe body of Ihe place, making the perpendicular
llF 18 !Oires, and Ihe faces 30.
The branehe. Da Eb of Ihe hOroIVOI k, IVhen pro–
dueed, lerminm on Ihe faces of Ihe ballions, wilhin 5
loifes of the Ihoulders. The dileh of Ihe hornwork is
12 toifes, and ils eounlerfearp parallel 10 the branehes ;
~nd in Ihe front ¡erminares al the Iho.lders, in the fame
manner as the grcat diteh before the barlions.
The eapit.1of Ihe «vclin before the fronl of Ihehorn–
work is 35 lUife; , and Ihe faces lerminate on the Ihoul–
ders, o/ mher 2 or 3 !Oifts beyond Ihem: and the dileh
before the ravelin is 8 toifes.
There are fOOletimes rctrenehmcnts made wilhin
the hornwork, fu eh as S. S: IVhieh are eonflruéled by
ereéling perpendieulars lOthe faces of Ihe raYelins, with–
in 25 toires of thei r extremities. This rCIrcnehmenl, like
. 11others, has a parapct turf.d only wilh a bermof 8f~et
bdore it; as lik,wife, a dilrh frolO 3 10 5 '1OIf,s broad.
Fig. 13' \V hen a hornwork is m,lde bl· fore Ihe b,lli–
on, the dlllanee DL o( Ihe front from Ihe angle
of Ihe ballion IS 100 loib, and Ihe ¡'"nchcs I<,rminale
on Ihe f.ces o( Ihe adj.ccm r;¡,clins \\ilh:n í !Oifes from
1h,ir exmmilic!; .11 the reJl is Ihe f,ll1\e as before.
S. CIj',jlrufl hn o{ r.r~"iI.;1''l.l'odJ.
J.)I,I~e LXXX IV. fi!l' J. r rom tI,e r. ,: angle of
e A T o N.
the r.lvelio, as a eenlre, ol.feribe an are of a eirele IVi:h
a rarlius of about 120 toif", euning Ihe capital of Ihe
,"vel,n produeeu al C; from Ihc poinl C, fet off Ihe
cOlds CH, CF, eaeh of Ihemequal 10110 loifes; and (IfI
eaeh o( whieh, as aneXIerior fide, eonllruél a fronl o( a
polygon of Ihe fa me dimenfions as in the hornwork; Ih,t
is, Ihe perpendicular Ihould be 18 loifes, the fam JO,
and Ihe branehes terminm on the faeel of the b,flions,
wilhin 25 lOiles of the Ihoulders.
The diteh is 12 toifes, the eapilal of the ravelin H,
and ils dijeh 8; thal is, Ihe fame as in Ihe homwork .
SometÍmes the erownwork is made 'before Ihe bafliGn,
as in lig. 2. lhe are is deferibcd from Ihe falianl angle
A of the baflion, IVilh a radiusof 120 loifes, as before.
and Ihe branehes tfrminale on Ihe faces of Ihe adj
ravelins IVilhin 25 roifes of Iheir eXIremilies; Ihe reH
of the dimenfions and eoollruélions are Ihe fame as before.
Hornworks, as well as erownworks, are never m,¿e
out when a large fpot of ground f.lls be)'ond Ihe (oni"–
cation, whieh mighl be advant'geous 10 an enemy in a
fiege, or lO eover fome galc or enlranee inlo a towo;
Q. Co.jlrl/aio. if Covrrl'wa)'l and Glaeil.
Although IVe have not hitheno menlioned Ihe eO'er!–
way, nevwhelefs .IJ forti"eations have one;
(or they are efleemed to be one of Ihe mOIl efl'cmial pans
of a modern fortifieation; and it is cemin. Ihe taking
lhe eOI'w -IVay, ·\Vheo ir is in a good eonuilion and well
defended, is genmUy the mol! bJoody atllon of lhe
fiege ,
After having eonflrut'led the body of I~e place. and
all the outlVorks "hieh are ¡hought neeefl'ary, Jines are
drawn parallel 10 Ihe oUlmofl eounterfearps of Ihe dilehes,
at 6toifes diflant (rom it ; and the fpace mnmn, inelude?
belweeo Ihat line and the eounterfcarp, will be Ihe eo–
vw-way required.
Fig. 3, There is io every re·enteriog angle of the
eounterfcarp a place of arms, oí; IVhieh is found by fe/–
ling off '0 toifes from the re-enterina angle a, on bOlh
fides from a to b, .nd from a 10 e; .;d from Ihe poínu
b, e, as eemres, ares are dtferibeu wilh a "drus of 15
loi(es, fo as to ioterfeél eaeh olhcr iD d; Ihen thc lines
dfawn from this inlerfeélion tO Ihe poinls b, e, will he
the faces of the plaees of arms. .
1f lioes are draIVo, parallel to the lines whieh lerm'–
nale Ihe eoven ",ay, and Ihe plaees of arms. al ~o toifes
d,flant from them, Ihe fpaee x, x, x, het"eeo .Ihefe
lincs and thofe whieh terminat, the eoverr-"Y, \VIII he
Ihe glacis.
At Ih,e exrremílies of Ihe placcs of arms. are tram–
fes made, fueh as v, l' , whieh ferves 10 inclo(, Ihem;
Ihefe Iraverfes are 3 tOlfes Ihlck. aOlI as long 2S Ihe
covert-\\'ay is broad; and a pafl'.lge is eul in Ihe ~lactS
rOllr.d Ihem, of about 6 or 8 fw . in order 10 Im'c a
free eommunication ~ ilh Ihe refl of Ihl· rO"f,,·way.
Th, re are alfo tral'tlfes of Ihe C"ne dilnl'"fion~ brfNe
every f, liaOl angle of Ihe b.fllon .nd OllllVO' ks. and are
in IItC fJlIle diret'lion of Ihe faee' llf ,ho(, 1I'0lks rrn,Ju–
eed ; anu the thieknefs lies at Ihe 1~l11c fiJe JS Ihe p'''–
pCIS.
The pafl" ges rnunel litefe J.,n IfJI ":,~ m Ilc\\"'c
from (, 10 8 feet lI'iJl'.
In