sed a telegraph with only one wire; the
signals to be read by the peculiar movements of an attracted pith-ball,
and Arthur Young witnessed his plan in action, as recorded in his diary.
M. Chappe, the inventor of the semaphore, tried about the year 1790 to
introduce a synchronous electric telegraph, and failed.

Don Francisco Salva y Campillo, of Barcelona, in 1795, proposed to
make a telegraph between Barcelona and Mataro, either overhead or
underground, and he remarks of the wires, 'at the bottom of the sea
their bed would be ready made, and it would be an extraordinary casualty
that should disturb them.' In Salva's telegraph, the signals were to be
made by illuminating letters of tinfoil with the spark. Volta's great
invention of the pile in 1800 furnished a new source of electricity,
better adapted for the telegraph, and Salva was apparently the first
to recognise this, for, in the same year, he proposed to use it
and interpret the signals by the twitching of a frog's limb, or the
decomposition of water.

In 1802, Jean Alexandre, a reputed natural son of Jean Jacques Rousseau,
brought out a TELEGRAPHE INTIME, or secret telegraph, which appears to
have been a step-by-step apparatus. The inventor concealed its mode of
working, but it was believed to be electrical, and there was a needle
which stopped at various points on a dial. Alexandre stated that he
had found out a strange matter or power which was, perhaps generally
diffused, and formed in some sort the soul of the universe. He
endeavoured to bring his invention under the eye of the First Consul,
but Napoleon referred the matter to Delambre, and would not see it.
Alexandre was born at Paris, and served as a carver and gilder at
Poictiers; then sang in the churches till the Revolution suppressed this
means of livelihood. He rose to influence as a Commissary-general, then
retired from the army and became an inventor. His name is associated
with a method of steering balloons, and a filter for supplying Bordeaux
with water from the Garonne. But neither of these plans appear to have
been put in practice, and he died at Angouleme, leaving his widow in
extreme poverty.

Sommering, a distinguished Prussian anatomist, in 1809 brought out a
telegraph worked by a voltaic battery, and making signals by decomposing
water. Two years later it was greatly simplified by Schweigger, of
Halle; and there is reason to believe that but for the discovery of
electro-magnetism by Oerst