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 May 30, 1782, suggested an alarm bell to call attention to the message. Lomond, of Paris, devised 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 Salvá 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 Salvá'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 Salvá 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 télégraphe 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