Scientific American Supplement, No. 384, May 12, 1883Various
Science
Scientific American Supplement, No. 384, May 12, 1883
Various
Science -- Periodicals
Finally, in 1844, Henry Highton took out a patent in England for a
telegraph working through electricity of high tension, with the use of
a single line wire. A paper unrolled regularly between two points, and
each discharge made a small hole in it, But this hole was near one
or the other of the points according as the line was positively or
negatively charged. The combination of the holes thus traced upon two
parallel lines permitted of the formation of an alphabet. This telegraph
was tried successfully over a line ten miles long, on the London and
Northwestern Railway.
[Illustration: FIG. 4.]
We have followed electrostatic telegraphs up to an epoch at which
telegraphy had already entered upon a more practical road, and it now
remains for us to retrace our steps toward those apparatus that are
based upon the use of the voltaic current.
* * * * *
Prof. Dolbear observes that if a galvanometer is placed between the
terminals of a circuit of homogeneous iron wire and heat is applied, no
electric effect will be observed; but if the structure of the wire
is altered by alternate bending or twisting into a helix, then the
galvanometer will indicate a current. The professor employs a helix
connected with a battery, and surrounding a portion of the wire in
circuit with the galvanometer. The current in the helix magnetizes the
circuit wire inclosed, and the galvanometer exhibits the presence of
electricity. The experiment helps to prove that magnetism is connected
with some molecular change of the magnetized metal.
* * * * *
ELECTRICAL TRANSMISSION AND STORAGE.
[Footnote: From a recent lecture in London before the Institute of Civil
Engineers.]
By Dr. C. WILLIAM SIEMENS, F.R.S, Mem. Inst. C.E.
Dr. Siemens, in opening the discourse, adverted to the object the
Council had in view in organizing these occasional lectures, which were
not to be lectures upon general topics, but the outcome of such special
study and practical experience as members of the Institution had
exceptional opportunities of acquiring in the course of their
professional occupation. The subject to be dealt with during the present
session was that of electricity. Already telegraphy had been brought
forward by Mr. W. H. Preece, and telephonic communication by Sir
Frederick Bramwell.
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