fortif: 
When batteries are ereffed at leifure, and are intended 
<lY a defence far fome years, it is bed to conftradt them 
df done or brick, or good loamy earth, according as the 
materials are neared at hand, or can be mod readily pro¬ 
cured, When made of done, tlie thicknefs of the para¬ 
pet is ufually about five feet; but this thicknefs is varied, 
according to the quality of the dene, or to the fize of the 
Cannon that may probably be brought by an enemy to fire 
On it. Parapets of brick are of fix, eight, or ten, feet 
thicknefs, according to the goodnefs of the materials, or 
the fervice it is to endure ; and the angles are generally 
Of done. A parapet made of good earth, and twenty 
feet thick, with the furface covered with green turf, will 
fetid the injuries of the weather for many years, and dand 
(he (hock of an enemy’s cannon the bed of any. 
As thefe more durable batteries are generally raifed 
4bove the level of the land or water which they are to 
Command ; fo it is ufual to make the floors of the era- 
brafurcs Hoping, the drip being on the outfide, about a 
foot and a half below the fill of the inner opening, that the 
Cannon may be pointed downward. When the embra- 
fures are cut through an earthen parapet, they are com¬ 
monly lined with brick ; or at 'lead the angles are made 
Of mafonry, thefe parts being the mod fubjedl to be in- 
lured by the weather. The bed embrafures are thofe 
made with a neck, by which a part of the opening becomes 
more contra tied, and confequently is better adapted to 
preferve the gunners and cannon from the enemy’s fliot, 
than when the cheeks of the embrafures are made draight. 
Although the axis or middle line of an embrafure 
fhould, if podible, be at right angles to the length of 
the parapet, yet it may fometimes be necedary to have 
■them oblique. When this happens, the infide of the pa¬ 
rapet mud be fo cut away, as to leave proper room for 
the front of the platform, that the wheels of the carriage 
may be drawn up againd the inner opening for the axis of 
the gun to lie in the axis of the embrafure ; but then the 
outfide of the parapet is to be drengthened, to compen¬ 
sate fufficiently for what is cut away within. 
To CONSTRUCT THE PLANS OF EMBRASURES.— Fof 
the plain embrafure, draw the axis AB, fig. 4, perpendi¬ 
cular to the parapet. For the front opening, make AC 
eAD, each from four to five feet. For the inner open¬ 
ing, make B F=BE, each from one foot to one and a quar- 
ter. Then draw FD, EC, for the cheeks of the embra¬ 
fure required. 
For the necked embrafure.- —Having drawn the cheeks for 
a plain embrafure as before ; from B, the middle of the 
inner opening, draw BC, BD, as in fig. 5. In the axis 
AB, take BG=2| or 3 feet; through G draw IH at 
right angles to BA, cutting BC, BD, in H, I, and join 
EH, FI, Then DIF, CHE, are the angular cheeks, IH 
being the neck or narrowing of the embrafure. 
For an oblique embrafure .■—Draw the axis ah, fig. 6 , 
in the diredlion where the gun is to command, and 
through any convenient point I, taken in ab, draw NN 
at right angles to ab. Make 1N=4 or 5 feet for the 
front opening, IP—1 or i£ foot for the inner opening, 
and 1Q4=4 feet for the front of the platform. Through 
N, CU an( l parallel to ab, draw NC, ND, cutting the 
front of the parapet in C, D ; and P p, Qcutting the 
infide of the parapet in q, q. Through q draw qr parallel 
to NN, cutting the former lines in F, B, E , r-, join ED, 
FC, and draw rs parallel to a line through B and C. 
Then the fpace qrs being cut away, the wheels of the car¬ 
riage can knock againd the line qr, and the axis of the 
gun will lie in the line Be intended for the axis of the 
embrafure. 
When the embrafures are to be expreffed in the para¬ 
pets of a plan drawn from a fmall fcale, it is done thus 
—-On the infide of the parapet RS, fig. 7, lay off as many 
times fix yards, in the points, c, c, c , &c. as the length 
©f the parapet will admit, unlefs redrained by particular 
circumdances; and from the points, c. c. c, £?c, draw lines 
VOL.VII. No. 452. 
CATION. 591 
to the front of the parapet, dividing it into parts of three 
yards each ; then taking the parts oppofite to the points c 
for the fronts of the embrafures, the other parts will re- 
prefent the frontof the merlons. The (haded parts (hew 
the'merlons, and the white angular fpaces exprefs tire 
embrafures. 
To DRAW THE PROFILE OF A BATTERY. —Let the 
ground line of the battery be A B, fig. 8, and BD that of the 
parapet, the inner (lope of which DH is formed by making 
Da— foot, and the perpendicular «H=6 or 7 feet : the 
crown of the parapet HI is formed by making b I a foot or 
two lower than aH ; and the front of the battery IB is 
found by making £B=z§ b I, when of earth, or —i of bt 
when of mafonry. Making DC=2| or 3 feet, gives C 
the fill of the embrafure, the floor of which CG is to dip 
a foot or two below the level line CF. The platform 
DE is 20 feet, the tail E rifing about fix inches above the 
level line AB : the lower double line reprefents the 
deeper laid lengthwife, and the upper double line (haded 
with the lines acrofs, expreffes the ends of the planks laid 
on the fleepers. 
Of RAMPS. 
When a battery is raifed above the level of the ground 
it is built on, there mud be made gentle dopes for the 
cannon to be drawn up and down, and alfo for the ealier 
communication of the troops poded there ; thefe dopes, 
to didinguifii them from the (lope ufually given to ele¬ 
vated works for theirbetter fecurity of Handing, are called 
ramps. The bafe of the (lopes commonly given to earth- 
banks for their fupport, is on the infide about a foot bafe 
for a foot of height, and on the outfide is about eight 
inches on a foot, or two-thirds of the height; that is, they 
rife twelve inches, on eight inches of bafe. But for the 
(lopes of ramps, the rife is only about two inches on 
twelve, or the length of the ramp’s bafe is fix times the 
height; and this is general, for the draught of carriages; 
but footways need not be of fo gentle a (lope, a rile of 
one foot in three may do well enough ; or, indead of 
ramps, dairs may be, and commonly are, ufed for the paf- 
fage of the foot. The breadth of a carriage-ramp is 
ufually about 10 feet, that breadth being fufficient for 
the carriage and foot-way befide ; but thofe for foot-paf- 
fage only need not be above four feet wide. Ramps may 
either rife on the fide of an elevated work, or againd a 
faliant angle of that work, or on each fide of an entering 
angle : according to the following confirmations: 
To CONSTRUCT A RAMP ON THE SIDE OF A BANK. —. 
Let XX, ZZ, fig. 9, be lines expreding the (lope of a 
bank equal to its height, which fuppofe to be twelve 
feet. Through A, the point where the ramp is to end* 
draw CB perpendicular to XX, and make AC of about 
10 feet. In ZZ take BD—4 times AB, or 16 yards, 
through D draw AE, and through C draw CF parallel 
to AE, cutting XX in G, and ZZ in F. Through F 
draw, at right angles to GF, the line /E, cutting XX in 
f, and AE in,E ; join’BE, and the lines GF, E A, EB, ex, 
prefs the ramp. It is fometimes proper to have ramps 
rife on'either hand for the convenience of carriages com¬ 
ing from the right or left j but they mud then be fo far. 
afunder, that fiiould a carriage he drawing up each at the 
fame time the horfes of one may pafs clear of thofe of the 
other. 
To CONSTRUCT A RAMP IN A 6ALIANT ANGLE OF A 
Bank.— This is done in the fame manner as in the fide of 
a bank ; oblerving that the end A, fig. 10, is taken fix of, 
feven yards from the faliant angle, when a ramp is to be 
conftrudied on both -fides; otherwife the ramp may end 
at the faliant angle X.—Or, from X, fig. ti, draw a line 
XN, bife£ling the faliant angle ; make XN=6 times the 
height, or equal to twelve yards, and on both fides draw 
a parallel line QR, at the didance from XN of half the 
breadth of the way; fuppofe at five feet didance from 
XN, Bifeft the angl? XQR with the. line QY, cutting 
7 N ' tit's 
