PHYSICS OF NINETEENTH CENT.-ELECTRICITY. 577 



he arrives at No. 15,389 in the year 1856. We shall have to de- 

 vote several pages to the account of Faraday's great discoveries of 

 magneto-electricity and induced currents. Leaving this account to 

 follow these necessarily brief notes of the life and labours of this truly 

 great man, we shall here quote a paragraph in which Dr. Bence Jones, 

 in his " Life and Letters of Faraday," refers to what Faraday had ac- 

 complished by 1830, that is, before he had entered upon his famous 

 electrical researches. 



" If Faraday's scientific life had ended at this time, when he finished 

 his higher scientific education, it might well have been called a noble 

 success. He had made two leading discoveries, the one on electro- 

 magnetic motions, the other on the condensation of several gases into 

 liquids. He had carried out two important and most laborious in- 

 vestigations on the alloys of steel and on the manufacture of optical 

 glass. He had discovered two new chlorides of carbon ; among the 

 products of the decomposition of oil by heat he had found the bicar- 

 buret of hydrogen, or benzol ; he had determined the combination of 

 sulphuric acid and the formation of a new body, sulpho-naphthalic 

 acid ; and he had made the first experiments on the diffusion of gases, 

 a subject which has become, by the researches of Professor Graham, 

 of the utmost importance. According to the catalogue of scientific 

 papers compiled by the Royal Society, he had had sixty important 

 scientific papers printed, and nine of these were in the * Philosophical 

 Transactions.' From assistant in the laboratory of the Royal Institu- 

 tion he had become its director. He had constantly laboured in the 

 great theatre, and he had probably saved the Institution by taking the 

 most active part in the establishment of the Friday evening meetings." 



For five and twenty years from the time when, in 1831, he began his 

 "Experimental Researches," Faraday's scientific career extends. After 

 the first ten years, the excessive strain upon his powers made it neces- 

 sary for him to task his brain less continuously, and for a few years 

 after 1839 the electrical researches were discontinued. During this 

 period of comparative repose he visited Switzerland and the Rhine. 

 In 1845 we find Faraday resuming his experimental researches in elec- 

 tricity, his principal discoveries at this period being the magnetization 

 of light, "the magnetic condition of all matter," and atmospheric mag- 

 netism. The series of electrical researches begun in 1831 came to an 

 end in 1855. It began with his two grand discoveries of the produc- 

 tion of electric currents by magnets, and the induction of currents by 

 currents ; then (to use the enumeration given by Dr. Bence Jones) it 

 continued with terrestrial magnetic induction, the identity of the elec- 

 tricities of the machine and of the battery, the investigation of con- 

 ducting power; then came electro-chemical decomposition, the induc- 

 tion of a current on ilself, static induction, the nature of the electric 

 forces, the electricity of the gymnotus, the source of electricity in the 

 voltaic piles, the electricity of steam, the magnetization of light, the 



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