The Sun.
London, England, 1861-09-21 00:00:00

HE COAST DEFENCES OF NORTE

CAROLINA.

(From the New York Herald)
Washington, Sept. 1.

Among the papers captured is the letter book of
Major William Beverhout Thompson, chief engi-
neer of the North Carolina coast defence, contain-
ing copies of his official correspondence with the
President of the Military Board and other State
officers of North Carolina, in relation to the sea-
coast defences from May 2 to August 1, 1861.
From this correspondence, which is devoted chiefly
to details in reference to the progress of various
fortifications, we extract the following, which are
of present interest.

In a letter to Colonel Warren Winslow, Presi-
dent of the Military Board, dated Fort Morgan,
June 10, 1861, be says
" I know that you will excuse any suggestion I
may throw out on a subject we all have so much
at heart—an effective defence of the State, and espe-
cially of the seacoast. It is true that the character
of our coast is a great moral protection to us; but
we must not lose sight of the fact that our
coast and every inlet upon it is as thoroughly
known to the Yankee captains of those vessels who
have been trading with us for years as to cur own
captains of vessels and the pilots upon our coast.
Every anchorage is well known to them—for ex-
ample, in the bight of Cape Hatteras, and in the
bight of Cape Lookout, and at other points where a
safe anchorage can be had and troops landed. What
lam driving at is this observed in the bill
passed by the Convention, calling for some 7,000
men, that there was no provision made for artillery.
I am satisfied, after giving this subject some reflec-
tion, about six batteries of light artillery would be
found most effective in repelling a landing of the
enemy at such points as may not be fortified. I
suppose that six batteries would be found to be
sufficient; but suppose that it should require,
ay forty-eight guns. With these batteries and
the country picket guards on the alert, informa-
tion could be sent at short notice of the
intention of the enemy to attempt a landing at
any point. He, no doubt, would be repulsed by a
well-served battery, supported by a force of in-
fantry, for he could not play upon the battery
from lis shipping without destroying his own
troops, and that they could not keep up an effec-
tive fire from the surf boats, as they would be
thrown about by the breakers in such a Way as to
render their aim uncertain and ineffective. Turn
the subject over in your mind, and I think that
you will come to the conclusion that, as they pro-
pose only to fortify the inlets, there are many other
points which can only be defended by flying
artil-
lery. The beach is one of the finest roads in the
world, hard and firm, and repaired by every tide.
They could land at certain points, pull their boats
across, and commit deplorable ravages."
The following letter gives an official account of
the condition of Fort Morgan and the surrounding
defences :

"Newbern, N.C., June 13, 1861.
"My dear Colonel,—l only received yours of June 1
at Fort Morgan n day or two since, on my return from
Fort Hatteras. Fort Morgan is now in condition to
make a strong defence, and I think fully prepared to
resist any force that is likely to be sent against it.
There are now 22 guns mounted—nine on the ram-
p rt, or upper tier, and 13 on the lower tier. Upon
the upper tier there are three columbiads, one ten-
inch and two eight-inch, two 32-pounders and six
21 pounders; on the lower tier 13 24 pounders. In
a few days I shall have mounted o❑ the upper tier
another 10-inch columbiads. All of those guns bear
upon the sea face of the fort, and three of them
on the land approach. Of the latter one of them
is the 10-inch columbiad; the second 10-inch colum-
biad, when mounted, will also bear upon the sea
face and the land approach. In addition to the
above heavy guns enumerated, I have four platforms
erected for 6-pounders, and the guns to place upon
them, two of which are in place; the balance, say
five guns, including one 121 b. howitzer, are tem-
porarily in the flank casemates. Four 6-pounders
will be placed on the platforms, near the salient
commanding the land approac. Two of them
should be placed in battery, so as to enfilade the
approach on the land side, between the fort and the
lighthouse, and the remaining 6-pounders either
placed on the land approach or used as circumstances
may require at other points. There were seven 301'o.
carronades went down some time since. They are
• but 4 feet 3 inches long, from the rear of the base
ring to the face, but can throw half a peck of canis-
ter or grape. I have therefore prepared a drawing
of a casemate carriage to mount them upon, and
shall place them in the flank casemates to enfilade
the ditches as soon as I can have them made, which
can be done at this point. I can then dispose of the
guns now in the casemates as suggested above.
" Fort Morgan is so important a point on the
line of our seacoast that I think the armament
should be made complete, for which I have hereto-
fore made a requisition. There were 25 guns,
chiefly 22 and 24 pounders, delivered there the
other day, but General Gwyun has ordered them to
be sent up to Newbern. Ido not think that all of
these guns are heavy enough for that fortress, as
there are several light guns among them. But there
are, say, four of those guns that would answer very
well. I have the platform down for another 8-inch
columbiad, but no gun to place on it, as the gun
intended for this purpose has been sent to Beacon
Island. There should be provision made for an 8-
inch columbiad for this platform. The sandhiils
have been cut down and removed for 1,000 yards
along the seashore, which is is effect extending
the ,glacis for that distance, over which direct as
well as cross fires are amply provided for when
we get all of the guns, which, with the small arms,
will render an assault of a numerous column next
to an impossibility.
"Before I left Hatteras I had mounted three 32-
pounders and 1 8-inch howitzer, the distance range
of which is between 3,000 and 4;000 yards. There
were four more requiring carriages—one for an
8-inch howitzer and the other three for 32- pounders.
I ordered some carriages to be sent down, and hope
to find them there on my arrival. Hatteras is a
difficult place to fortify, from the fact of the want
of proper revetting material. I discovered some
marshes about half a mile in the interior, from
which I am now getting a sod which, so far, seems
to answer quite well. The bar at Hatteras is just
one mile from the battery, which is commanded by
all of the guns. I hardly think, after this work is
finished, a flotilla can get in the harbour.—Yours
respectfully,