The Express.
London, England, 1858-10-07 00:00:00

IT* 1t431r.%.

THE ATLANTIC TELEGRAPH.

(nos ows OWN

VALINI'LL, Oar. 4.

While all the net of the world is busy with con-
jectures and speculations relative to the probability
of the premat Atlantic cable ever becoming a prao-
tied mans of communication between Europe and
Ameliokat this secluded little spot, which is supposed
is be the centre of all information on the subject,
everything remains dull and quiet enough. All the
eminent electricians, who for more than a month
past have been busy in performing a variety of
scientific experiments with the line, have left, with
the exeeption of Mr. Henley ; and even the few
occasional strangers and tourists whom the fame of
the cable brought to this part of the world have long
ceased to arrive. The stories of wonderful pheno-
mena observed by the country people in con-
nexion with the first success and ultimate
failure of the cable are now no longer heard, and
people now think and speak of an Atlantic Tele-
graph as if as secerpriee for its accomplishment had
never existed. All here are now obliged to admit
reluctantly that the present cable is a failure, and
the faint hopes which were indulged in a short time
ago, that one of the principal injuries to the cable
was near the shore and within reach, are now aban-
doned. One day, to all appearance, the fault
mends to a considerable extent, and daring the
receiving periods the ever-varying earth currents
are watched, distorted, and deserted, in the hopes of
di ervering something that may be construed into a
I signal or message from Newfoundland—but to no
purpose, for even the alight and regular deflections
of Professor Thomson's delicate galvanometer,
which were at first mistaken for "rever-
sals" from America, are now attributed to
the varying nature of the faults. Though a con-
siderable part of the injury that has occurred to the
cable is due to circumstance over which human
foresight could have no control—as, for instance, the
tempestuous weather which universally prevailed
during all the expedition—yet the many and dis-
appointing failures which have occurred have
brought with them valuable experience which will
prevent their recurrence during the laying of any
future deep-sit lines. A variety of experiments
have lately been tried, both by Professor Thomson
and Mr. Henley, to discover the amount of fault or
bare surface of the conductor which would prevent
the current passing through the line altogether, and
they have come to the conclusion that several inches
of total loss of insulation in one place would not
interrupt the whole of the electric current at once,
though the points of leakage would soon be totally
oxidated away by the decomposition of the
salt water in contact with them, if posi-
tive currents of electricity were used, while, if
only a minute flaw existed, the use of the powerful
currents of high tension electricity, such as were
at first need with the cable, would very soon destroy
the wire altogether at the point of resiatanes. The
supposed difficulty of working through the cable
after it was submerged, which was so much talked
about a short time ago, has turned out to be alto-
pther a mistake, and therefore the high tension
induction coils which were made by Mr. White-
house were not only unnecessary, but absolutely
hurtful and dangerous—unless the whole length of
the line was most perfectly insulated in every inch
of its vast length, which of coarse it is impossible
to expect that anything made by human hands
ooeld be. The retarding influences of induo-
Lion which were so much spoken of while
the cable was lying at Ileyharn were pro-
bably due to the inductive influence of one
layer of the cable lying over another in the
soil, for so little has it been experienced since the
cable has been laid that Professor Thomson thinks if
the line was in fair condition it could be worked
through with ease with • few battery cells of
Daniel's osestant battery. A great variety of inter-
esting experiments have been performs I to show
the kind of electricity beet suited for working
through the line, both in • perfect and imperfect
condition, and the results which have been arrived at
an both ireful and interesting. The high tension
electricity from the induced coils was found to burn
up and destroy • wire where • fault in the gotta
perch& was made. The second experiment was
made with discharges from Henley's mageeto-elee-
trie machine. This was found to astir a
slight lose through the fault, but not to injure the
wire at the point of egress in any way as keg as
negative discharges only were sent through. The
direct battery current, of great quantity, bat low
tension electricity, was found to answer best. and to
cause WI injury to the cable and to suffer lam loss
through the bait, but some copious currents of this
low tension electrisity am now unable to make the
cable show signs of activity even with the most
delicate arrangesesat of Professor Thomson's refloat-
ing galvanometer. Mush hes been said about this
beautifully sensitive little instrument, yet but few
know its nature or the advantages it possesses over
other galvanometers in observing very minute currents
of electricity. It consists of • coil of vary fine imi-
tated wire, in the interior of which is suspended •
very mall mirror of the finest microscope
glass, to the back of which are fastened two magnetic
needles not more than a quarter of an inch in
length. The two needles, with the reflecting mirror
they bear, not weighing more than two grains, are
suspended by a single fibre of silk. When the in-
strument is in me a ray of light is thrown upon the
minor, and is reflected upon an index board. The
very faintest currents of electricity are measured by
these means, for the very faintest deflection of the
needles, caused by an almost imperceptible current
of electricity passing through the coil, of course is
very perceptible upon the index board by the
motion of the reflected spot of light. Mr. Henley
has also a needle galvanometer here, most beauti-
fully sensitive, and he is now constructing one
which will be sensibly affected by the small quantity
of electricity developed by the motion of the muscles
of the body. Mr. Henley's magnetic machine, as pre-
viously stated, is now regularly used every day, both
is sending "reversal" signals, and sometimes even
1 weeds. It is impossible to say definitely that they are
received at the other end yet; from what is known of
the nature and action of those magneto-electric

currents on overground lines there can 17e little doubt,
if they do not pass the fault in the cable, no electric
carnet ever will. Indeed, rnmours have already
reached this place, but for their authenticity it is
Impessible to vouch, that intelligence has been re.
rived from Newfoundland of the receipt there of
several of the words and messages sent by Henley's
magnetic machine. Even 'opposing this to be the
eam, sad that on some of Mr. Henley's instruments
brag sent out to Newfoundland a regular oommuni-

4:eit is re-established, it would he wise of the
aimaemiders and those oaanected with the company