The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1866-07-06
THE ATLANTIC TELEGRAPH.

mailing gInstruments-The WlreWOrked
without Insulation - Programme Of
Operations.
In the London ines OF June %, we find the
following interesting account of the prcpara-
tions for the Atlantic Telegraph expedition,
which is to start next week. II will be seen
that some Improvements have been made in the
apparatus to be used in this expedition, and
that remarkable experiment has demonstrated
the feasibility OF working the conducting wire
without insulation.
The Times says;-'If any illustration were
ever needed to show the un1inching determine
ton OF English enterprise no more signal eX-
ample could be pointed out than In the repeated
costly and almost yearly efforts made to establish
permanent electrical communication between
this country and America Within week from
this date the fifth expedition organized Tor this
purpose will leave England. In 1867 the first
effort was made, and failed, when about three
hundred miles from the Irish shore. In 1858 it
was again attempted, with the two halves of the
cable slowed in the Niagara and Agdnlenenon;
and the terrific hurricane which both vessels
met with then, no doubt did serious injury to
their easily injured freight. Nevertheless, the
effort was persevered with, and some one hun
dred miles we're laid and lost between the two
ships. Again the wire squadron as 1t was
called, returned to Ireland, to start again for
ano,her attempt and to the astonishment OF all,
the damaged cable was not only laid, bat
actually worked with cearness for some days,
when IT gradually became incoherent, then ram
bling with occasional CLEANS OF intelligence, till
at last it became utterly Ineligible, aud so died
L u0nNDDliy
expedition of last year failed, and to this day 1t
is not known whether the injury to the cables
insulation was caused by accident or wanton
mischief.
"The commercial loss upon these failures has
been great; but even out of the evil has come
some good, for in the interim the science of
making, testing, and laying cables has so much
improved, that an undetected fault in an insu-
lated wire has now become literally impossible;
while so much are the instruments for signalling
improved, that not only can a slight fault be
disregarded, II necessary but it is even easy to
work through submarine wire with a foot of
its copper stripped and bare to the water. This
latter result, astonishing as it may appear, has
actually been achieved for some days past with
the whole Atlantic cable, on board the Great
Easter n. Out of length of more than 100
miles, coil has been taken from its centre, the
copper conductor stripped clean of its insula-
lion ior q foot in length, and in this condition
lowered over the vessels side till 1t rested on the
ground. Yet, through this, the clearest signals
have been sent-so clear, indeed, as at one time
TO raise the question whether it would not be
worth while to grapple for the first old Atlantic
cable ever laid, and, with these new instruments
working gently through il for year or so at
least make It pay its cost.
'Nothing, in fact, can give a better idea of
the change which has come over the science
of submarine telegraphY than by the statement
OF the manner in which the three cables OF
1858, 1865, and that of this year have been con-
structed. The actual constituents of each is as
tolloNs:-
CONDUCTORS.
"Conductor in lS5S.-A copper strand, con.
sisting OF seven wires (slx laid round one),
and weighing 107 lbs. per nautical mile.
"Ditto, lS65.-Copper strand, consisting of
seven wires (six laid round one), and weighing
800 lbs. per nautical mile, embedded for solidity
in Chatterton's compound. Gauge of single
wire 'O4S-ordinary ls gauge. Gauge of strand
144-ordinary No. 10 gauge.
''Ditto in 1S66.-Same.
INSULATION.
s'Insulator in IS5S-Gutla percha laid on in
three coverings, and weighing 26l pounds per
knot.
'Insulation in 1S65.-Gutta percha, four
layers of which are laid on alternately with
four thin layers OF Cbatterton's compound. The
weight of the entire insulation, 400 pounds per
nautical mile. Diameter of core, '464; circum-
ference of CORE 1892.
"Ditto, l666.-Same,
EXTERNAL PROTECTION
''External Protection in 185S.-Eghteen
strands of charcoal IRON wire, each strand COM
posed of seven wires (siX laid round one), laid
spirally round the core, which latter was pre-
Viously padded with serving of hemp satu-
rated with tar mixture. The separate wires
were each 229 gauge; the strand complete was
No. IA gauge.
'Ditto l865.-Ten solid wires of the gauge
'O95 (No. l9 gauee), drawn from Webster and
HorStalfs homogeneous iron, each wire sur
sounded separately with five strands of Manila
yarn, saturated with preservatve' compound,
and the whole laid spirally round the core
which latter is padded with jute yarn, saturated
with preservative mixture.
'Ditto lS66.-Ten solid wires of the gauge
'095 (No l3 gauge), drawn from Webster anc
Horstall's homogeneous iron, and galvanized
each wire surrounded separately with five
strands of white Manila yarn, and the whole
laid spiraly round the core, which latter il
padded with ordinary hemp saturated with pre-
< servatiye mixture
WEIGHT IN AIR.
''Weight in air in 1853, 20 cwt. per nautica
mile.
''Ditto, 1866, 35 cwt. qrs. per nautical mile.
'Ditto, 1866, 81 cwt. per nautical mile.
WEIGHT IN WATER.
''Weight in water in 1868, 1874 cwt. per naut
cal MILE
DITTO 1865, Ia cwt. per nautical mile.
'Diuo, 1866, l44 CIVIL. per nautical mile.
BREAKING STRAIN.
'Breaking strain in 1858, 8 tons, cwt., O
equal to 4'85 times its weight in water per knot
weight in little less than i've miles depth {
water.
''Ditto, 1865, tons 15 cwt or equal to
times its weight in water per knot; that is
say, the cable will bear its own weight in eleve
miles depth OF water.
Ditto, 1866, tons cwt., or equal to
times its weight in water per knot; that is t
say, the cable will bear its own weight in twely
miles depth OF water.
DEEPEST WATER TO BE ENCOUNTERED.
deepest Water TO be Encountered, l85S-24(
fathoms
'Ditto l665-24OO fathoms.
"Ditto l866-24OO iathoms.
CONTRACT STRAIN.
"Contract Strain, ls5s-Equal to 4'S5 times il
weight per nautical mile in water.