Michael Faraday, his Life and Works. 423 



the circumstances, depending either on the nature of the chemical 

 action or the number of voltaic pairs associated, which exert an 

 influence on these two characters of the current. In a word, he 

 establishes such a correlation between that which occurs in the 

 interior of a pile, and that which takes place in the electrolyte 

 interposed between the poles of this pile, that it is impossible 

 not to admit (with him) that electrolytic decomposition is nothing 

 but a form of chemical affinity transferred from the pile into the 

 electrolyte decomposed. 



Wishing to obtain an idea of the quantity of electricity which 

 is associated with the particles of which matter is composed, he 

 endeavours to estimate that which is necessary for the decompo- 

 sition of a grain of water, regarding it, as he is justified in doing, 

 as equivalent to that produced by the direct chemical action (of 

 the acidulated water upon the zinc) which decomposes this grain 

 of water. He arrives at this incredible result — namely, that this 

 quantity of electricity, appreciated by the heat evolved by it in 

 traversing a fine platinum wire, is superior to that manifested in 

 800,000 discharges of a battery of Leyclen jars, charged by thirty 

 turns of a powerful plate-machine, and consequently equivalent 

 to that constituting a violent flash of lightning. 



The researches of which I have been speaking were made in 

 1833, 1834, and 1835. I had previously paid attention to the 

 same questions, and had arrived by somewhat different methods 

 at the same conclusion w r ith Faraday — namely, that it is in che- 

 mical action that resides the origin of the evolution of electricity 

 in the voltaic pile, Faraday frequently alludes to my investiga- 

 tions in a very kind manner ; and subsequently (in 1840) he 

 wrote me a letter in which he said that, being a thorough ad 

 hcrent of the chemical theory, he had just attacked the ques- 

 tion directly, as I had already done, by demonstrating that con- 

 tact alone, if not accompanied by chemical action, is not a source 

 of electricity. The memoir in which he probes this question to 

 the bottom is the last which he devoted to this department of 

 electricity. In it, by means of a multitude of ingenious experi- 

 ments, he* demonstrates that the presence of an electrolyte (that 

 is to say, of a liquid which is at once a compound and a con- 

 ductor of electricity) is indispensable for the production of elec- 

 tricity in a voltaic couple ; he varies his experiments in a thou- 

 sand ways, sometimes by exhausting the number of chemical 

 compounds employed as electrolytes, sometimes by the interven- 

 tion of temperature or of other agents ; and he concludes by 

 showing by general considerations the improbability of the ex- 

 istence of a force of contact. 



We may say that this last work, a precious supplement to the 

 preceding ones, has rendered perfectly evident the truth of the 



