On some new Ekctro-chemical Vhanomena. r2j 



laston, in the year ISOl *, succeeded in imitating the effects by 

 means of the electrical machine, and thus experimentally de- 

 monstrated the identity of common and Voltaic electricity- 

 More recent investigations, and especially the admirable re- 

 searches of Sir H. Davy, have fiilly established the correctness of 

 these views, and have shown that the different action of the Vol- 

 taic pile and the electrical machine depends chiefly upon the 

 qiiantihj of electricity in the former being great, while its tJilen- 

 sily is inconsiderable, and vice versa. 



In the following lecture I shall have the honour of presenting 

 the Royal Society with some new inquiries connected with these 

 objects of research, and have much pleasure in adducing facts 

 which throw further light upon this interesting department of 

 chemical science, and which harmonize with the opinions of the 

 able philosophers alluded to. 



^ § n. 



When the flame of a candle is placed between two surfaces in 

 opposite electrical states, the negative surface becomes most 

 heated : this circumstance was considered by Mr. Cuthbertson 

 as indicating the passage of electric fluid from the positive to the 

 negative surface f. 



-Mr. ErmanJ has shown that certain substances are unipolar 

 in regard to the electricty of the Voltaic pile ; that is, that they 

 are only susceptible of transmitting one kind of electricity. The 

 insulated flames of wax, of oil, of spirit of wine, and of hydrogen 

 gas, only conduct positive electricity ; dry soap, on the contrary, 

 and the flame of phosphorus, -under the same circumstances^ only 

 transmit negative electricity. 



Sir H. Davy§ considers the result of Mr. Cuthbertson's ex- 

 periment to depend upon the unipoLarity of the flame, which 

 would render it positive, and cause it to be attracted towards the 

 negative pole. 



On perusing these statements, it occurred to me that they ad- 

 mitted of another explanation, and that the appearances might 

 be connected with the chemical nature of the substances em- 

 ployed, I repeated Mr. Cuthbertson's experiment, and found 

 that when the electrical machine was in weak action, the nega- 

 tive surface not only became hot sooner than the positive, but 

 that the smoke and flame of the candle were visibly attracted 

 towards it. I now removed the candle, and substituted the, 

 flame of phosphoras, vvhen the appearances were exactly re- 

 yersed; the positive surface now became considerably warmer 



* Pliil. Trans 1801, p. 435. t Practical Electricity. 

 J Aunales de CJiimie, 1807, tome Ixi. p. 1 13. 

 § EleuiciitfccirClitm. riiilob. vol. i. p. 177. 



than 



