FORTIFICATION. 
axis of the oval is to the lefs; and therefore the-front C D, 
on the 
3 ry are ey the exte ean 
the ftronger will be the front 
he line BE — ane the 
portion to th ee oe and ae of its fides; fo that a 
dodecagon is ftronger than an oCtagon, when length 
of their fides is the fame. ‘H as it is found dif- 
ficult to pedis a polygon in an ellipfe or oval, the fol- 
more eafy method will anfwer the purpofe. Re- 
duce the fot of ground to be fortified to the igure ACEG 
. 2.) and draw *, parallel to each other; 
» pe erpendicular to thefe lines, and at equal t 
diftance from the points B and and let their interval be 
equal to that of the aide BE and "A F: then draw DC, 
G H, parallel to A F and B E, and equally eer anes 
them; and from their ntere ici »G, with DG, 
CH, as _ defcribe ar be with a radius equal toC D 
to interfed t s AF, BE, in A, B, 
" 
fufficient ; in a 
If the fides cannot eafily be made equal, then 
AB, EF, on the narroweft part of the polygon, 
fhould be the longett, —_ i is ee nes 
: cannot in ae 
fianding uch are the ufual fortifications 
ef cities, font: places, &e. 
Temporary fortification 1 is that erected on fome emergent 
146, &c. 
te fortification i is ane built with defign to remain a 
elter for ages 
are for the ee = main- 
ing a poft, er paflage ; ar about camps, as cir- 
cu sina Fl ie contravallations, redoubts, ae batte- 
ries, &c. h article. 
) 10N, Marin dagen ps by way 2 
diftin€tion from /and fortification. art of 
r 
be urs. in 
eons works for 2 4. ie 
open to the fea, on a curved, or ftraight bold rp and 
has | ita fufficient depth of water and good anchor 
age, the fhips, in this fituation, may be well eiefended by 
ida but near faved water’s e = en each fide of the anchor- 
lace, fo ved as three batteries, 
one ee ne “he other, a furnifhed with a faticient 
number of ‘mae carrying fhot from twenty-four to forty- 
i pou own, in this fituation, may be defended 
papers wall, well flanked, built along the fhore, 
belide the fortifications on the land fide. | The works along 
the-fhore fhould-be carried fo near to the water’s edge, that 
troops, attempting. to land hed the cannon of a fleet, 
might not find ground on which to nag: area Mer 
arther, when a harbour, being a bay, a fhoal o 
ifland ly ying before its entrance, a ftrong ae ‘hould . built 
upon ie ifland, in a place where it sal pir ait the en- 
trance on both aes, if the ifland be n 
may co the avenues to the 
alfo be vaifed on the 
ing the mouth of tet 
a bay, whofe asia forning the entrance, ftretch into iors 
fea, and approach one another within cannon fhot ;, 
or more forts; and, if po 
alfo be built within the harbour’s mouth in fuch a manner, 
that its cannon can rake the fhipping fore and aft as they 
come in. 
When a harbour is formed by a clufter of iflands, it is 
eee fortified, if ae channel anaes the pane is not 
wide for the mand ef c n from r both 
fon ; but if it ce se cade the fopiae ae aes there 
muft be defended from the batteries on the fhore. When 
the harbour lies in an inlet, or r river, fome miles above its 
mouth, a fo uilt at each point of the entrance, when 
the paflage lies ftraight, be commanded fide 
fide and rs between them and the harbour, but 
fhould be built where they can command a reach at leaft 
or be fo placed at the bends, as to command two adjacent 
reaches: See Forts, and "Robe ertfon's Treat. of Marine 
Fort. part ii. oo 2. For the fortification of harbours by 
ooms, od oM. 
For ee NE - rofile of a, is a aria rea of a 
see fettion of awork, ferving to fhew thofe dimenfions 
which cannot be reprefented i in plans, and are neceffary in 
the building of a fortification. This profile is conftruéed 
in the following manner: provide a {cale of equal parts, 
adapted to the per oa height of — work, ¢. gr. 
let a b, Plate be a {ca 
aaa let A B uel. the ‘level of the ground ene fo at 
tho parts of the fortification which are above the furface 
line j in the profile. Fro e point A, i 
ake A C = four toifes oe ee fect, for ie interior talus or 
flope of the rampart; at C erect a ei aa gone C D of 
three toifes eighteen feet for the height of the rampart 5 
ara the point or eae an indefinite line DN parallel 
> inWw oa = 5 toifes for the seers of 
the terre-plein of the eee at t E 
oe EF= 
2 feet from the height of the ban- 
quette, and dra 
w F H parallel to DN, making FG and 
it; on the point 
perpendicular HI = 44 feet from the height of the pa- 
rapet above the banquette. From 4 ia the indefinite 
I - parallel to DN, in which = 14 foot, 
w H L which will be the ini fide of the 
eee take LK = 3 toifes for the thicknefs of the 
parapet, and from the point K let fall the Aes e line KP, 
perpendicular to the line A B, and produce it below A:B: 
in ok line take = 24 feet, and draw the 
e upper part of ie par apet, which is a talus, that the 
foldier on the banquette may be able to difcover the covert- 
way 
