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F o R T 1 F 1 e A T ION.
PORTIF'CATION. lhe arl of fonif)'ing a 10ll'n,
or olher place; or of putting lhem in flleh a pollure
of def,nee, lhal Cl"ery one of ilS pans dtfeoos, and is
d.rcndcd by fome other pans, by means of ramprtS.
pMapm, mom, and olher buhy. rks; 10 lhe cnd,
~ fmall number of mm "ithin. m,y be able lO defend
¡hemfdres for a eonlidmble time aeainll lhe alT.ults of
a numerous army withoul; fo lhal lhe <oemy in ato
laeking lhem, mul! of neeenit)' fuffer glM lol!.
Furtifiealion is tilher ancier.l or modern, regular or
irregular. Aneienl fonilication, al tirl!, eonfilted of
'IIalls or defeoCC! made of lrunks aod olher branches
of tret:s mixed Wilh emh, 10 fecure lhem ag. inll lhe
macks of the eoemy. T his was aflerlllards .ltered 10
Ilone \Valls, on which IVere raifed breall.works, behind
",hi,h lhey made ufe of their dans and arro"s in feeuri·
ty. Modero fotliC,calioo is lhal whieh is ftanked aod de–
fended hy ballioo! and OUl "'ork!, the nmpans of whieh
are fo folid, lhal lhey eaonOl be bw down bUl by lhe
continu.1 fi,e of feoenl baneries of e,nnon. Regular
fonificatioo, ¡, lhal buill in a regular polygon, lhe
(¡des and ang~ of whieh are al! equal, being eom'
monly aboul a mu(kel·Olol from eaeh olher. Irregu·
lar fonificalion, 00 lhe , is lhal where lhe
fid<s and angks are nOl uniformo equidillant, or equal ;
,:hieh is .owing tO lhe irregulariry of lhe ground, valle)'s,
mm, bIlis, aod lhe like.
SECTION l . Of Regular Fort!pcntion.
THt anof regularfonificalion may be dillinguifhed in·
to lWO pam, !'iz. the elemeomy or lheorelical, aod
l'"élical.
The e1emenlary pan conGlls in uacing lhe plans and
profiles of a fonifiealion on paper, Wilh fcales aod como
palTes ; a~d 10 examine lhe fyllems propofed by dilfmnl
amhors, '" order 10 difcover !heir advantages and dif·
advaotages.
And ~he praélici.1 pan confills in formiog • projeél
oLa fOrllficallOn, according 10 lhe nalure of lhe ground
and Olher necelTary cireumllanees, 10 trace il on lhe
groun~,. ~n~ lO exeeule lhe proj,él, togelher Wilh all
lh~ mllllary building., foeh as magazine" Ilore·houfes,
bndges, ec.
No~wilhllandiní! all lhe improvementl whieh harebecn
made lo lh .. :ut of fo" ifyiog fine~ lhe invcolion of gun·
powder, lhal of anaeking is Ildl f"perior lO il : cngi.
nem .have Iried in rain 10 render th~ arl\'antl~rs 6f afuro
l~e,,,on e~ual lO lhof. of lhe ,:I.lek; lhe fuperioril)' of
1 e befiegm hre, lo~cl her wilh the grldler number of
m
f
"", ohliLes generally, fooo:l or later, lhe btG~sed ;0
:J"mlt.
Th~ ~rwdl improrrmtnt made io 1!'C on of auaekill"
VoL.1 1. 1\0. p 2 "
h~ppencd iD the year 1697, "hen M. V.uban made firft
ufe of ricoehel firing al Ihe Gcge of Ath, whel'eby the be·
fieged plaeed behind lhe p.c<pels were as mueh cxpofed
10 lhe fire of the beficgcrs as if lhere had beeo nune;
",hereas before, lhey had been feeure as long as lhe para·
pel "as nOl demolifh ed: and lhe 1V0rf[ is, lhal lhere can
b~ no remedy found 10 prevenl lhi, enfiL,ding Wilhout
f,lIing ioto inconvenieneies.Imoll asbad aslhofe which we
endeavour 10 ~.
Ahhough aUlhoC! agree as lO lhe geoeral form io lhe
prefen! manner of fonifying, yet lhey mon ly differ in
panicular eonllruélions of lhe pans. As il would be bOll!
n«dlefs and fuperfluous to ueal of all the differenl me·
thod! hilherto propofed, lVe {hall conlenl ourfelves wilh
explaining lhofe ooly, ",hieh are moll efieemed by lhe
bell judges, and haye beenmollly pUl in praéliee.
C.nJlruf/ion of ~l. V. uUN'! fI1rlh,d.
'Inis melhod is di.ided inlo liule, meao, and greal;
tbe liul~ is ehieOy ufed in lhe eonllruélion of eiladels.
lbe mean in lhal of all fons of lowns, and the greal in
particular eafes only.
\Ve 0 ..11 gi.e lhe eonllru8ion of lhe mean, as beiog
moll ufeful, and refer lhe reader 10 lhe lable hereafler,
for lhofe dimenfioos whieh are diffcreot in lhefe fevml
fonifiealions.
[Plale LXXXIII.fig. l.] Tneribe in a eirele a polygon
of as many fides as lhe fonifiwion is defigoed lOhave
fronls; let AB be one of lhe fides of half an exagon,
whieh bifeél by lhe perpendicular CD: divide half AC
of it ioto oine equal pans, and ooe of lhefe ioto teo o·
thm; lhen lhefe divifions will ferve as a fcale 10 con·
Ilruél all lhe pans of lhe fonificali0n, and mh of lhem
is fuppofed lO be a loife or fathom, lhal is fix Freneh
feel ; and lherefore lhe whole (¡de AB is fuppofed 10 be
18010ifes.
As lhe dividing a line inlO f0 many equal pans, is
troublefome aod ledious ; il is more eoovtnieot lOh,,'c
a feale of equal pan! by which lhe ,yorks may be coo·
Ilruéled.
Tf lherefore, in lhis eafe, lhe radius is lakenequal 10
180 roifes, and Ihe eirele defcribed lI'ith lhat radius be·
ing divided into fix equal pans, or lhe ra¿ius .beiog caro
ried'fix limes rOllnd, you ",ill have .0 exa~oo inrcribed';
AH being bifeéled by lhe perpcndie~lar CD as btfore,
feloff ,1) tOires from C 10 D, aod draw lhe indefinire
lines AOC, BDF', in w"ieh lah the pans AE, HB,
eaLh equal 10 50 toifes ; from lhe Clnlre E drfcribe an
are through lhe poiot H, meeling AD in C, ar,rl from
lhe centre H defrrihe an are lhro\l&11 lhe puinl F., meet·
iog BD in F; Or which is lhe f,me. mJke eaeh of lho
Enes EC HF (qu,1 10 lhe .tinanee EH; llt"n the line,
joinining lhe poinn A,E,F,G, II ,H, mil b: the prio';I,,1
¡,r olldioe of lhe fl'Onl.
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