328 EXPERIMENTAL INVESTIGATIONS. 



In a paper published in the ' Philosophical Transactions ' 

 for 1843, p. 1 1 1, I have shown that we may oppose a chemical 

 action by a physical one (electrolysis by a vacuum), that 

 antagonising chemical by physical tension, they mutually 

 oppose each other. I believe the converse of this experiment 

 has been made by M. Babinet, who by physical compression 

 has prevented the development of chemical action. 



I have also described in the ' Philosophical Magazine ' for 

 November 1845 certain phenomena which appear to me to 

 be irreconcileable with received chemical views ; and though 

 I then believed that the theory of Grotthus would be obliged 

 to give way, I now incline to think that some of our chemical 

 doctrines must ere long undergo a revision. 



It is rather surprising that the valuable applications of 

 which the phenomena of voltaic ignition are capable, and the 

 fertile field which (as I believe) it presents for discoveries, 

 both physical and chemical, should have been so completely 

 neglected. It is true that, until a recent period, the imper- 

 fection of the voltaic battery rendered accurate and continued 

 experiment on this subject difficult of performance, but still 

 much might have been done. Davy made several experiments 

 on the voltaic disruptive discharge, which, in many points, 

 may be regarded simply as very intense ignition ; but I am 

 only aware of two experiments of his on voltaic ignition ; one, 

 in which he employed it in an exhausted receiver to examine 

 to what extent the radiation of heat was carried on in vacno ; 

 and another, already alluded to, in which, by immersing a 

 portion of an ignited wire in water, he observed that it con- 

 ducted in some inverse ratio to its heat. 



I have made a vast number of experiments on the voltaic 

 arc or disruptive discharge, in various media ; * when this is 

 taken in a medium incapable of acting chemically on the elec- 

 trodes, the phenomena are those of intense ignition of the 

 terminals, which are dissipated in vapour and condensed upon 

 the interior of the vessel in which the discharge is taken. I 

 have examined some of these deposits, and they appear to 

 consist of the metal of the terminals in a finely-divided state ; 



* Phil. Mag. t June 1840; Lit. Gaz. and Athenceum y Feb. 7, 184$, 



