The Sun.
London, England, 1857-09-08 00:00:00

ELECTRIC TELEG.RAP.II.

The following from Sir W. B. O'Shaugnessy re-
lates to the question as to the effect of heat in im•
pairing the efficiency of submarine cables, such as
that lately constructed for the Atlantic elegraph.
It appears unquestionable that if this cable were
purchased for shipment to Suez or Kurrachee there
would be considerable danger, unless certain pre-
cautions wore taken, of the gutta percha covering
'Acorn:lig softened from the temperature to which
it would be subjected in crossing the tropics. Ap-
parently, however, there is no reason to believe
that it is at present injured, or that there would
be any serious difficulty in devising methods for
its safe conveyane3
" observe with surprise a statement from the
Gutta Percha Company in the Times of this morning
that large quantities of gutta percha covered telegraph
wire have been shipped to various Indian ports, and
never, to our knowledge, has the E light ea t damage oc-
curred.'

•' I regret much to be constrained to adduce facts at
variance with thia statement. _

" In 1853 the East India Company gent out to India,
in sailing vessels, 700 miles of gutta percha covered
wire, made by the company who address you,and packed
by them in solid deal cases. On opening these cases in
India, some weeks after arrival in the cold season, and
without any exposure in the interval, it was found that
the copper wire had in many places been forced through
the gotta percha, which bore evident marks of softening
by heat.
" We further found that a still more serious change
had taken place partially, and was in rapid progress, by
which the gutta percha became brittle, broke off from
the wire whenever bent, and lost all its insulating
power. This change had occurred within the unopened
cases. To save as much as possible of the wire we coated
about 200 miles with tarred yarn, and this arrested the
change for a time. Still, eventually we had to condemn
as useless about 500 miles of the wire.
" These facts have been reported officially to the Go-
♦ernmeut of India and to the East India Company, and
have been communicated by myself personally to Mr.
Statham, the respected manager of the Gutta Percha
Company's works. His illness and abeencie from London
have, doubtless, been the cause of the Gutta Percha
Company advancing, without full knowledge of the cir-
cumstances, the statement which appeared this morning.
I am (Nita certain that they would not wilfully mislead
' the public ou a matter of fact, whether trivial or impor-
tant. _ .

" The change in the gutta percha from the plastic to
the brittle state is the effect of oxidation. This is proved
by an elaborate series of analyses made, at my request,
by Profesor Hoffmann, of the Royal College of Chemis•
try, on samples of the gutta percha which had been
altered in India.
" Gut'a percha in its natural state contains—
Carbon
Hydrogen 12'40
" When altered by prolonged heat and keeping (this in
cases not even once opened) two substances are formed
containing—

No. 1. No. 2.
CArbon 02.79 ... 6710
Hydrogen . ... 9'29 10 09
Oxygen
"These substances are totally useless as insulators.
Wire surrounded by gutta percha thus altered must be
considered electrically as so much uncoated metal.

"The facts now published give a warMng which should
not be negleotod. If ignored, or lightly valued, the re-
sult will be great 103 M of capital and infinite disappoint-
ment to the community. I have done my duty without
bias or prejudice id making this communication to all the
parties concerned, although I am well aware that I
might better consult my own comfort by remaining alto-
gether silent.
" I wish it, however, to be clearly understood that I
consider it quite practicable to send out the Atlantic
cable, in suitable vessels and with special appliances,
.
without much risk from the causes of injury above de ,
scribed. My object is at present to warn those concerned
not to send it out in the AgaMCMIIOO, or in ignorance of
the facts described, and neglecting the precautions these
facts suggest. Further, I see no difficulty in manufac•
turing a cable in which the tendency
to oxidation and
spontaneous heating and
influence of heat from ex-
ternal causes may be both effectually counteracted.—
I am, tir, your obelivit.. B. rvant,
O'SLIAUGUNESSY,
"Chief Superintendent of Telegraphs in India.
" 965, Gresham-house, Broad-street, Sept. 5."

AN A POSTROTHE WORTH EIGHT THOUSAND POUNDS.
—Monsieur de M-- died on the 27th Feb. last, leav•
jog a will, entirely in his own handwriting, which he
concludes thus :—" And to tertify my affection for my
nephews Charles and Henri de M--, I bequeath to each
d'eux (i. e., of them) tor deux, i. e., two) hundred thousand
francs." The paper was folded before the ink was dry,
and the writing is blotted in many places. The legatees
assert that the apostrophe is one of those blots ; but the
hoir-at-law, a legitimate son of the defunct, maintains,
on the contrary, that the apostrophe is intentional. It
wilt be curious to watch the result of the contest.—
National Ilfagazin.
MELBOURNE GRAMMAR SCHOOL, AUSTRALIA.—The
Rev. Dr. J. E. Bromby, curate of Hull, has been ap•
pointed to the head mastership of this school, and will
leave England in the course of a few days. Dr. Bromby
was formerly principal of Elizabeth College, Guernsey.
lie was educated at St. John's Cullge, Cambridge,
where he graduated in 1832, being ninth wrangler and
third in the second class in classics.