The daily exchange. [volume] (Baltimore, Md.) 1858-1861, 1861-04-12

We present our readers this morning an accu-
rate plan of the Harbor of Charleston, S. c., with
the Government Notifications, and the defences
erected by the Confederate authorities, and append
full description of the different works.
FORT SUMTER.
Fort Sumter is a modern truncated pentagOnal
tort, built upon artificial island at the mouth of
Charleston harbor, three and three-eighths miles
from the city OF Charleston. The island has for its
base sand and mud bank, with a superstructure,
1t we may so term it, of the refuse chips from sew
eral Northern granite quarries. These rocks are
hrmiy embedded in the sand, and upon them the
present tOrtiication is reared. The island itself
cost half million dollars, and was ten years
in construction. The fortiication cost another
hall million dollars, and at the time of its
occupancy by Major Anderson was so nearly COM
pleted to admit the introduction of its arma-
ment The walls of solid brick and concrete
masonry, built close to the edge of the water, and
without BERN. They sixty feet high, and
from eight to twelve feet in thickness, and are
pierced for three tiers of guns on the north, east,
and west exterior sides. Its weakest point is on
the south side, of which the masonry is not only
weaker than that of the other sides, but it is
protected by any flank fire, which would sweep the
wharf.
Once landed, an entrance may. at the present
state Of the construction, be easily made for the
blinds of the lower embrasures though six inches
in thickness, may yet be easily blown away, and
even if this was impossible, scaling ladders
tected in this manner. The work is designed for
armament of one hundred and forty pieces of
ordnance of all cabres. Two tiers of the guns are
under bomb proof casemates, and the third up
per tier open or, IN military parlance, barbette;
the lower tier for fortytwo pouader paixhan guns;
the second tier for eight and ten-nch columbiads,
for throwing solid or holw shot, and the upper
tier for mortars and twenty-four pound guns. The
full armament of the fort, however, had not arrived
there when Major Anderson took possession; but
since its occupancy by the present garrison no eff
forts have been spared to place the work in eff
cient state of defence, by mounting all the available
guns and placing them in salient points. AS we be-
fore remarked, the full armament of the fort is not
in position as only seventy-fve of the hundred
and forty guns required for it mounted.
Eleven paixhan guns are among that number, nine
of them commanding Fort Moultrie, which is with
in easy range, and the other two pointing towards
Castle Pinckney, which is we'll out of range. Some
of the coumbiads, the most effective weapon for
siege defensive operations. not mounted Four
OF the thirtytwo FOUNDER barbette guns pivot
carriages, which give them the entire range of the
horizon, and others have horizontal sweep of fire OF
$50 degrees In addition to these weighter prepara-
tions for Defence the walls pierced everywhere
for N Iskets, of which there endless numbers
EeeaS I'd me maga1ns contaha sapp1H
of shet rvmdo- SsnelIs for years siege, and
large amount OF miscellaneous artillery stOFes.-
The garrison is amply supplied with water from
artificial wells, which are supplied with the fire.
quent showers of rain. In defensive strate-
glcal point OF view, Fort Sumter radlates its fire
through all the channels from the approach to
Charleston, and has a full sweep of range il its
city side. The fort is sufficiently out of
range from land artillery attack so that all ap-
prehensions for preaching it from that source may
be put at rest, unless by guns of superior caibre
The maximum range of the guns from Sumter is
three miles; but for accurate firing, sufficient to
hull We ssel, the distance would require to be re-
duced one-half of that figure. The war garrison Of
the fort is six hundred men, but only seventy-nine
Of that number are within its walls, with the Ia
borer rs-l09 all told