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Poincare, Lucien

"The New Physics and Its Evolution"

It was in 1838,
however, that Professor C.A. Steinheil of Munich expressed, for the
first time, the clear idea of suppressing the return wire and
replacing it by a connection of the line wire to the earth. He thus at
one step covered half the way, the easiest, it is true, which was to
lead to the final goal, since he saved the use of one-half of the line
of wire. Steinheil, advised, perhaps, by Gauss, had, moreover, a very
exact conception of the part taken by the earth considered as a
conducting body. He seems to have well understood that, in certain
conditions, the resistance of such a conductor, though supposed to be
unlimited, might be independent of the distance apart of the
electrodes which carry the current and allow it to go forth. He
likewise thought of using the railway lines to transmit telegraphic
signals.
Several scholars who from the first had turned their minds to
telegraphy, had analogous ideas. It was thus that S.F.B. Morse,
superintendent of the Government telegraphs in the United States,
whose name is universally known in connection with the very simple
apparatus invented by him, made experiments in the autumn of 1842
before a special commission in New York and a numerous public
audience, to show how surely and how easily his apparatus worked.


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