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 Oersted, in 1824 the chemical telegraph would have come into practical use. In 1806, Ralph Wedgwood submitted a telegraph based on frictional electricity to the Admiralty, but was told that the semaphore was sufficient for the country. In a pamphlet he suggested the establishment of a telegraph system with public offices in different centres. Francis Ronalds, in 1816, brought a similar telegraph of his invention to the notice of the Admiralty, and was politely informed that 'telegraphs of any kind are now wholly unnecessary.' In 1826-7, Harrison Gray Dyar, of New York, devised a telegraph in which the spark was made to stain the signals on moist litmus paper by decomposing nitric acid; but he had to abandon his experiments in Long Island and fly the country, because of a writ which charged him with a conspiracy for carrying on secret communication. In 1830 Hubert Recy published an account of a system of Teletatodydaxie, by which the electric spark was to ignite alcohol and indicate the signals of a code. But spark or frictional electric telegraphs were destined to give way to those actuated by the voltaic current, as the chemical mode of signalling was superseded by the electro-magnet. In 1820 the separate courses of electric and magnetic science were united by the connecting discovery of Oersted, who found that a wire conveying a current had the power of moving a compass-needle to one side or the other according to the direction of the current.