204 Electrochemical Researches on 



quicksilver, and the common metals, by which I had suc- 

 ceeded in decomposing the alkaline earths, on alumine and 

 silex j but without gaining distinct evidences of their having 

 undergone any change in the processes. 



Obliged to seek for other means of acting upon them, it 

 was necessary to consider minutely their relations to other 

 bodies, and to search for analogies by which the principles 

 of research might be guided. 



Alumine very slowly finds its point of rest at the negative 

 pole, in the electrical circuit ; but silex, even when diffused 

 in its gelatinous state through water, rests indifferently at 

 the negative or positive poles. 



From this indifference to positive and negative electrical 

 attractions, following the general order of facts, it might be 

 inferred, that if these bodies be compounds^ the electrical 

 energies of their elements are nearly in equilibrium ; and 

 that their state is either analogous to that of insoluble neu- 

 tral salts, or of oxides nearly saturated with oxygen. 



The combinations of silex and alumine, with acids and 

 alkalis, as well as their electrical powers, were not incon- 

 sistent with either of these ideas ; for in some respects they 

 resemble in physical characters, flucfe and phosphate of 

 lime, as much as in others, they approach to the oxides of 

 zinc and tin. 



On the idea that silex might be an insoluble neutrosaline 

 compound, containing an unknown acid or earth, or both, 

 and capable of being resolved into its secondary elements, in 

 the same manner as sulphate of barytes, or fluate of lime, I 

 made the following experiments : 



Two gold cones*, connected by moistened amianthus, 

 were filled with pure water, and placed in the electrical cir- 

 cuit, a small quantity of carefully prepared and well washed 

 silex was introduced into the positive cone : the action was 

 kept up from a battery of two hundred plates, for some 

 hours, till nearly half of the fluid in each cone was exhaust- 

 ed ; the remainders were examined ; the fluid in the cone 

 containing the silex was strongly acid ; that in the opposite 



* The same as those described in Phil. Trans. 1807, p. 6. — See Phil. Mag. 

 vol. xxviii. p. 5. ^ 



cone 



