538 SPECIAL METHODS OF DISCOVERY. 



and carried them out in the form of inventions, and thus 

 discovered the fact that messages might be transmitted 

 to great distances by means of electricity. It was largely 

 by devising suitable experiments that Faraday, in the 

 year 1831, succeeded in discovering magneto-electricity. 

 Ritchie, in 1834, by making an experiment, succeeded in 

 causing water to rotate by means of electro-magnetism, 

 and is said to have caused a magnetised needle to remain 

 suspended in the air, without visible support, by the same 

 power. Bottot of Turin, in the year 1833, by means of 

 experiments, is said to have been the first to decompose 

 water and some solutions by means of thermo-electricity. 1 

 Faraday also, by testing the chemical theory of voltaic 

 electricity by means of experiments, in the year 1840, 

 proved the hypothesis and made the discovery of the 

 chemical origin of the voltaic current. In 1847, Loomis 

 suggested the experiment of determining differences of 

 longitude by means of the electric telegraph. 



It was by balancing an unmagnetised steel needle on a 

 pivot, very delicately, in a horizontal position, then mag- 

 netising and replacing it, that Robert Norman, in the year 

 1576, discovered the magnetic dip or inclination. Hooke, 

 in the year 1684, by heating rods of iron, and allowing them 

 to cool in the direction of the magnetic meridian, discovered 

 that they became magnets. In 1775, Graham suggested 

 the experiment of using a vibrating magnetic needle for 

 discovering changes of magnetic intensity, and various 

 discoveries have since been made by means of it. About 

 the year 1777, Beccaria made the experiment of passing 

 an electric shock through a needle, and stated that the 

 needle thereby acquired the remarkable property of point- 

 ing east and west, when freely suspended. 2 In 1802, 



1 Mrs. Somerville, Connexion of the Physical Sciences, p. 363. 



2 I have repeated this experiment, but without success. 



