2^4 *^^^ H* Davy on the Substances produced 



but their general views differed from mine in this respect, as 

 they supposed, that no part of the inflammable matter was 

 derived from silica, and they likewise reasoned on the pheno- 

 mena with more caution. 



At the time that my conclusions were drawn, I was igno- 

 rant of the true nature of the muriatic acid. After I had tried 

 in vain to decompose oxymuriatic gas, and after I had found 

 that the compounds of this substance with phosphorus, sul- 

 phur, and the metals combined with ammonia without any 

 decomposition, and produced compounds in which no oxygen 

 could be discovered; I was forcibly struck by the analogy 

 between the oxymuriatic and the fluoric compounds, and led 

 to doubt of the justness of my ideas respecting the nature of 

 fluoric acid. 



I tried an experiment on the comparative quantities of fluate 

 of lime, formed from equal volumes of silicated fluoric acid 

 gas, one of which had been acted upon by potassium, and 

 then exposed to solution of ammonia, the other had been 

 absorbed by solution of ammonia : and I found the proportion 

 of calcareous fluate nearly one-third larger in the latter case. 

 This result at first seemed favourable to my early ideas, that 

 the acid contained a peculiar inflammable basis, which was 

 separated by the potassium, and existed in the combustible 

 substance insoluble in water ; but it could not be considered as 

 decisive on the question, for, it occurred to me as possible, 

 that this substance might be silicum, or the basis of silica united 

 to a much smaller proportion of the fluoric principle, than 

 that existing in silicated fluoric acid. 



During the period that I was engaged in these investiga- 

 tions, I received two letters from M. Ampere, of Paris, con- 



