278 EXPERIMENTAL INVESTIGATIONS. 



These experiments are strongly corroborative, and seem 

 to me conclusive as to the relation between the action of the 

 gas battery and catalysis by spongy platinum. Experiment 26 

 is also remarkable in regard to the binary theory of electro- 

 lysis, but upon this point I will not here enter. 



Applying the hypothesis of Grotthus to the gas battery, 

 we may suppose that when the circuit is completed, at each 

 point of contact of oxygen, water, and platinum, in the oxygen 

 tube, a molecule of hydrogen leaves its associated molecule of 

 oxygen to unite with one of the free gas ; the oxygen thus 

 thrown off unites with the hydrogen of the adjoining molecule 

 of water ; and so on until the last molecule of oxygen unites 

 with a molecule of the free hydrogen ; or we may conversely 

 assume that the action commences in the hydrogen tube. In 

 these hypotheses we should bear in mind that we proceed 

 by steps which nature, as hitherto tested by experiment, has 

 not recognised. All we can safely predicate of the actions at 

 anode and cathode is that they are correlations ; although 

 they take place at a distance, the one has no more been proved 

 to take place without the other, or before the other, than 

 height has been proved to exist without depth. I therefore 

 allude to this hypothesis, not as explicitly adhering to it, but 

 because it is generally received, and may tend to associate 

 the action of the gas battery with the ordinary phenomena of 

 electrolysis. 



A number of hypotheses has been and may be proposed 

 to account for these and other mysterious phenomenal rela- 

 tions ; they all agree in being assimilations of what is un- 

 familiar to what is familiar. They are undoubtedly useful as 

 illustrations, and it is as such that they have hithero contri- 

 buted to advance science. It is, however, a curious circum- 

 stance, and worthy of some consideration, that the voltaic 

 hypothesis of Grotthus, the emissive and undulatory hypo- 

 theses of light and heat, and, as far as I am aware, all physical 

 hypotheses hitherto propounded, represent natural agencies as 

 effects of motion and matter. These two seem the most 

 distinct, if not the only conceptions of the mind, with regard 

 to natural phenomena ; and when we try to comprehend or 

 explain affections of matter which are not obviously modes of 



