Curiosities of Science, Past and Present: A Book for Old and Young

Name: Curiosities of Science, Past and Present: A Book for Old and Young
Author: Timbs, John

Timbs, John

Science

First, as to the _Cable_. In the ordinary wires by the side of
a railway the electric current travels on with the speed of
lightning--uninterrupted by the speed of lightning; but when a wire
is encased in gutta-percha, or any similar covering, for submersion
in the sea, new forces come into play. The electric excitement of the
wire acts by induction, through the envelope, upon the particles of
water in contact with that envelope, and calls up an electric force
of an opposite kind. There are two forces, in fact, pulling against
each other through the gutta-percha as a neutral medium,--that is,
the electricity in the wire, and the opposite electricity in the film
of water immediately surrounding the cable; and to that extent the
power of the current in the enclosed wire is weakened. A submarine
cable, when in the water, is virtually _a lengthened-out Leyden jar_;
it transmits signals while being charged and discharged, instead of
merely allowing a stream to flow evenly along it: it is a _bottle_
for holding electricity rather than a _pipe_ for carrying it; and
this has to be filled for every time of using. The wire being carried
underground, or through the water, the speed becomes quite measurable,
say a thousand miles in a second, instead of two hundred thousand,
owing to the retardation by induced or retrograde currents. The energy
of the currents and the quality of the wire also affect the speed.
Until lately it was supposed that the wire acts only as a _conductor_
of electricity, and that a long wire must produce a weaker effect than
a short one, on account of the consequent attenuation of the electrical
influence; but it is now known that, the cable being a _reservoir_ as
well as a conductor, its electrical supply is increased in proportion
to its length.

The electro-magnetic current is employed, since it possesses a treble
velocity of transmission, and realises consequently _a threefold
working speed_ as compared with simple voltaic electricity. Mr. Wildman
Whitehouse has determined by his ingenious apparatus that the speed
of the voltaic current might be raised under special circumstances
to 1800 miles per second; but that of the induced current, or the
electro-magnetic, might be augmented to 6000 miles per second.

Public-domain text, read in full here on John Shaqi.

Opening the text

Curiosities of Science, Past and Present: A Book for Old and YoungTimbs, John

Science

Curiosities of Science, Past and Present: A Book for Old and Young

Timbs, John

Science

First, as to the _Cable_. In the ordinary wires by the side of
a railway the electric current travels on with the speed of
lightning--uninterrupted by the speed of lightning; but when a wire
is encased in gutta-percha, or any similar covering, for submersion
in the sea, new forces come into play. The electric excitement of the
wire acts by induction, through the envelope, upon the particles of
water in contact with that envelope, and calls up an electric force
of an opposite kind. There are two forces, in fact, pulling against
each other through the gutta-percha as a neutral medium,--that is,
the electricity in the wire, and the opposite electricity in the film
of water immediately surrounding the cable; and to that extent the
power of the current in the enclosed wire is weakened. A submarine
cable, when in the water, is virtually _a lengthened-out Leyden jar_;
it transmits signals while being charged and discharged, instead of
merely allowing a stream to flow evenly along it: it is a _bottle_
for holding electricity rather than a _pipe_ for carrying it; and
this has to be filled for every time of using. The wire being carried
underground, or through the water, the speed becomes quite measurable,
say a thousand miles in a second, instead of two hundred thousand,
owing to the retardation by induced or retrograde currents. The energy
of the currents and the quality of the wire also affect the speed.
Until lately it was supposed that the wire acts only as a _conductor_
of electricity, and that a long wire must produce a weaker effect than
a short one, on account of the consequent attenuation of the electrical
influence; but it is now known that, the cable being a _reservoir_ as
well as a conductor, its electrical supply is increased in proportion
to its length.

The electro-magnetic current is employed, since it possesses a treble
velocity of transmission, and realises consequently _a threefold
working speed_ as compared with simple voltaic electricity. Mr. Wildman
Whitehouse has determined by his ingenious apparatus that the speed
of the voltaic current might be raised under special circumstances
to 1800 miles per second; but that of the induced current, or the
electro-magnetic, might be augmented to 6000 miles per second.

Public-domain text, read in full here on John Shaqi.

Curiosities of Science, Past and Present: A Book for Old and Young

Curiosities of Science, Past and Present: A Book for Old and Young

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