u8 THE POPULAR SCIENCE MONTHLY. 



and France, making the acquaintance of the most distinguished 

 men of science in those countries. Volta's first scientific paper, 

 on the Attractive Force of the Electric Fire {De Vi attractiva 

 Ignis electrici), which "was addressed in 1769 to P. Beccaria, is 

 described by M. Biot as giving only an imperfect explanation of 

 electric phenomena, and as illustrating the characteristic trait 

 of his mind, which led him rather to sure deductions from 

 facts which he could experimentally follow out than to the 

 formation of sound general theories. That part of the paper 

 in which he showed the application of his theory to the gen- 

 eration of electricity is mentioned by Prof. Arthur Schuster as 

 being of historical importance, because in it can be traced the 

 germ of many future discoveries. He supposed that all bodies in 

 the natural state contain electricity in such proportions that they 

 are in electrical equilibrium, and that this was shown in the ex- 

 perimental results obtained by rubbing one metal with another. 

 But when bodies are brought into close contact, as in friction, he 

 considered that the attractions of electricity and matter might 

 alter, according to Boscovich's theory that attraction and re- 

 pulsion alternate at short distances, and that a new equilibrium 

 would establish itself. He expressed a belief that a disturbance 

 of electrical equilibrium takes place during the progress of chemi- 

 cal action, in which the particles of matter change their position ; 

 attributed the want of proof of the fact to experimental difficul- 

 ties ; and hoped that he would succeed in obtaining evidence of it ; 

 and he thought that atmospheric electricity might be accounted 

 for in accordance with these views. 



In his second paper he attempted to explain electrical insula- 

 tion by the supposition of a repulsion between the insulating 

 matter and electricity. His experiments, made in 1775, on the in- 

 sulating property which wood acquires when impregnated with 

 oil, led to the construction of the electrophorus, an apparatus 

 which acts as a permanent and inexhaustible source whence elec- 

 tricity can be drawn at will. A letter of Volta's to Priestley is 

 preserved, dated June 10, 1775, announcing the construction of 

 this instrument, and asking the English chemist, as the historian 

 of electricity, how far the discovery was new. Volta's experi- 

 ments on the electrostatic capacity of conductors, described in a 

 letter to De Saussure in 1778, were in advance of anything that 

 had been published up to that time, although Cavendish had al- 

 ready experimented on the subject ; but Cavendish's results were 

 not published for a long time afterward. Volta's ingenious 

 efforts, pursued continuously, to improve the electrophorus, led 

 up to the discovery of the electric condenser, the description of 

 which, and the account of its applications to the study of electri- 

 cal phenomena, were published in the Philosophical Transactions 



