The Press.
London, England, 1857-10-31 00:00:00

THE PRESS, OCTOBER 31,1857.

moderately computed. It is, however, evident to me that
by improvements in the arrangement of the signals them-
selves, aided by the adoption of a code or system constructed
upon the principles of the best nautical code, as suggested
by Mr. Whitehouse, we may at least double the speed in
the transmission of our messages. In one word, the
doubts are resolved; the difficulties are overcome; success
is within our reach; and the great feat of the century
must shortly be accomplished !"

The magneto-electric induction coils here at-
tributed to Mr. Whitehouse are claimed by
Mr. Thomas Allan, who in 1852 published, and
we believe patented, this method of trans•
mitted electricity. The weight of the cable
which afterwards destroyed it is thus de-
scribed :

The completed cable weighs from nineteen hundred-
weights to one ton per mile, and bears with impunity a
direct strain of four tons being placed upon its strands.
Some pieces have borne a direct strain of more than five
tons without breaking. When, however, the cable is im-
mersed in sea water, its relative weight will, of course, be
diminished. Its downward pressure in salt water will be
a little under fourteen hundredweight per mile. The
greatest depth over which the vessels will have to pass in
depositing the cable in the Atlantic will be a little more
than two miles; consequently it enough of the ropo were
suffered to hang motionless from one of the vessels to
reach the bottom in this depth, the strain needing to be
borne by the rape would be under a ton and a half. During
the process of paying out, however, the cable will be con-
stantly in motion, with only a sufficient restraining power
upon it to control and regulate its egress from the ship, until
this is by a rate slightly faster than the progress of the
vessel. The strain will hence really be considerably less
than a ton and a half for two miles. Here again another
modifying influence also comes into play, to act still fur-
ther in the relief of the strain. The cable will not only
be somewhat buoyed up, so to speak, by the water, it will
also be buoyed up by the influence of friction. It will
never descend, as it is payed out, in a vertical line, or
reach the bottom in a course even approaching to a per-
pendicular direction. This will be because friction of the
sides of the cable against the water will retard the sinking
of the mass. The amount of this retardation, and the
length which will consequently lie between the stern of
the vessel and the bottom of the sea, will be determined by
the rates at which the cable is payed out, and at which the
paying-out vessel moves. In real fact, so far from there
being any strain, consequent upon the weight of the cable,
sufficient to injure its integrity, there will be only just pull
enough to drag it gently out of the vessel over the revolving
sheaves. The strain will be like the strain which is put
on the filmy thread of the silkworm, as it is reeled rapidly
off from the cocoon, and not like that which is put on a
fixed rope, when a heavy weight is hung freely upon its
lower end. The buoyancy and friction which will hinder
the cable from dropping directly to the bottom of the sea,
will sustain and uphold it as it falls. The specific gravity
of the cable, and its flexibility, have been so planned that
it will be laid down at the bottom of the ocean as gently as
if it were passed through men's hands, or over pulleys all
along its course in the yielding water. The frictional
influence which will thus "lend a hand " to deposit the
Telegraph Cable in the Atlantic, is identica with the
cause of the regularly progressive diminution of the speed
of the plummet's descent in deep-sea soundings, already
alluded to in speaking of the method employed for elimi-
nating the horizontal pull of diversely moving currents,
from the vertical drag of the plummet. There is, however,
one important difference between the case of the cable and
that of the sounding plummet. The plummet drags down
a line which is lighter than the water, and which there-
fore has more buoyancy than friction attaching to its move-
ment. The cable is altogether heavierthan water, and has
more friction than buoyancy. Friction will produce more
retardation, comparatively, in the movement of the cable,
than in that of the sounding plummet and line.

It is easy now to see that this reasoning is
fallacious ; but for mathematical proofs of
this we must refer our readers to the scientific
journals, or the proceedings of the British
Association at Dahlia this year, where Cap-
tain Blakeley, 11. A., read a paper proving that
a great and uninterrupted strain is necessary
to prevent a great waste of cable, if the latter
be heavy. Indeed, the projectors tell us
(pp. 52 and 53) that they provided six hun-
dred miles of extra cable, although that be-
tween Varna and Balaklava was laid down
during a storm with only three miles and
three-quarters over the direct distance between
the terminal stations. The reason is that the
Black Sea cable was light, not covered with
heavy iron wire to sustain its own weight
during the process of submerging the cable
only, after which we are told (p. 40) that " the
" rust may cat up the irou external coat as
" soon as it pleases."
Mr. Bright, the engineer, confesses to re-
quiring 1,000 miles as a margin for next year.
Are we to understand that a lighter, smaller,
cheaper, and more easily conveyed cable would
be curried away by currents into such curves
as to require more than 1,000 miles of margin?
Let the managers of the Atlantic Telegraph
Company reconsider the question, and bear in
mind that what they have already accom-