330 EXPERIMENTAL INVESTIGATIONS. 



SUPPLEMENTARY PAPER ON CERTAIN PHENOMENA 

 OF VOLTAIC IGNITION, AND THE DECOMPOSI- 

 TION OF WATER INTO ITS CONSTITUENT GASES 

 BY HEAT. 



Phil. Trans., R.S. Received November 26. Read November 26, 1846. 



IN selecting the above title I endeavoured to give as clear an 

 enunciation of the phenomena to be described in the paper as 

 was consistent with the brevity usual in a title. 



An exception has, however, been taken to it, that as the 

 effects of decomposition are produced by ignited platinum, 

 the phenomena may result from that obscure mode of action 

 called catalysis. That I did not intend to exclude from con- 

 sideration any possible action of the substance employed will 

 be evident from the paper itself, in which I have called atten- 

 tion to the general production of catalytic effects by solid 

 bodies. 



Whatever value or novelty there may be in the facts I 

 have communicated is the same, whether they be regarded as 

 resulting from catalytic or from thermic actions. If the action 

 be catalytic, it is one absolutely the reverse of that usually 

 produced by platinum, and therefore just as much at variance 

 with received experience as decomposition of water by heat 

 would be, the effect of platinum, like that of heat, on the 

 elements of water having been hitherto known only as com- 

 bining them. With regard to any theoretic views I may have 

 advanced, I by no means attach the same importance to them 

 as I do to the facts themselves, though I consider it necessary 

 for the collation of facts, and desirable for the progress of 

 science, that an author pretending to communicate new results 

 should give with them the impressions which led to their dis- 

 covery, and the inferences which he regards as immediately 

 deducible from them. No expression can be given to facts 

 which does not involve some theory ; and admitting the diffi- 

 culty (perhaps insuperable) of correctly enunciating new phe- 

 nomena, and the probability of future discoveries entirely 



