The Sun.
London, England, 1858-10-20 00:00:00

EXPORTS.

Cotton.—Almost all descriptions of this staple have ad-
vanced one rupee in value; and in some instances transac-
tions have been made on European account.

Oil Seeds.—This market has assumed an active tone, and
the prices of the articles have advanced.
Opium.—The inquiry for this drug has lessened during
the fortnight, and we quote the rate of the day at Its. 1,310
per chest. The steamer Singapore, which lately left for
the Chinese and other ports, took 1,200 chests on board.
Tonnage.—No improvement has taken place in the rates
of freights, the rates of the day being £1 to £1 10s. for
Liverpool and London; and for its. 5 per candy.
Exchange.—We quote London credits, at six months'
sight, at 2s. ; documents, at 2s. 0 d. ; and bank rates,
at is. Hid. On Calcutta, at 60 days' sight, Its. 991 ; on
Madras, at 30 days' sight, Its. 991 ; and on China, at 60
days' sight, Rs. 215 per 100 dols.

THE TASMANIAN SUBMARINE CABLE.

The Government of Tasmania has taken the
lead among our colonies in procuring for itself the
means of submarine communication. It has entered
into a contract with Messrs. M'Naughton and Co.,
of Launceston, Tasmania, to construct and lay
down 240 miles of cable, so as to connect the Island
of Tasmania with Victoria in Australia. From the
George Town Heads, the entrance into the port of
Launceston, the cable will be stretched across the
ocean to King's Island, and from this island across
the sea again to Cape Otway. Victoria and Laun-
ceston will thus be brought into telegraphic com-
munication.

The manufacture of the cable has just been com-
pleted by Mr. W. T. Henley, at his manufactory
at Greenwich. In diameter it is about equal to
the Atlantic cable, but differs from it in its con-
struction. The copper conductor consists of a
single solid wire of No. 16 gauge, instead of a
strand composed of seven small wires twisted
together. This single solid conductor is covered
with gutta percha, in two distinct layers. The
gutta percha covered wire is then surrounded with
a covering of Russia hemp saturated with a mixture
of Stockholm tar, linseed oil, and Russia tallow.
Around the hemp covering an outer one of iron
wire has been spun by Mr. Henley. This iron
sheathing consists of ten solid iron wires of No. 8
size. In the Atlantic cable the outer covering of
iron wire was composed of eighteen wires, these
wires not being solid, but each composed of a
strand of seven smaller ones.

The new cable seems sufficiently elastic for all
useful purposes : it weighs two tons to the statute
mile. It has been manufactured simultaneously in
two lengths, and as each length was drawn out of
the room where it received its iron sheathing it was
passed through a bath of tar, to preserve it from
rust; it was then immersed in a tank of water. The
value of this last process was shown by a flaw in
the cable being detected, which allowed an escape
of electricity from the conductor. This escape did
not manifest itself until the cable had been in the
water tank four days. Without the application of
this test the escape might not have been discovered
till after the submersion of the cable in the ocean.
The construction of the Tasmanian cable has been
superintended by M. Latimer Clarke (the engineer
of the Electric and International Company of Eng-
land) and Mr. W. H. Butcher, of Hobart Town. It
has been tested by an extremely sensitive galvano-
meter. This galvanometer shows a deflection of
50 degrees for a current of electricity generated
only by a pair of plates, after passing through the
whole 240 miles of cable and the earth. So perfect
is the insulation of the cable, that when it is charged
by a powerful current of electricity, its extremity
not being in contact with the earth, this delicate
galvanometer scarcely indicates any deflection.
We understand that the O'Meor screw steamer is
expected to arrive in the Thames on Friday, the
22d inst., to ship the cable. The submergence will
be entrusted to the care of Mr. W. H. Butcher.