Sir H. Davy's Account of some new Experiments^ &c, 6^ 
the action of a soluble salt of lead on fluate of potassa or fluate 
of ammonia, is immediately decomposed, when moist, by am- 
moniacal gas, and a white powder separates from it, which 
must contain oxygen, as it gives carbonic acid by being ignited 
with charcoal; but dry fluate of lead may be fused in ammo- 
nia without undergoing the slightest alteration, and the pre- 
sence of water, which may furnish oxygen to the lead and 
hydrogen to the fluoric principle, seems absolutely necessary 
for the production of oxidated bodies from the fluoric combi- 
nations. 
I obtained analogous results by acting on silicated fluate of 
ammonia and fluo-borate of ammonia by chlorine when the 
salts were moist, or when the gas was not free from vapour, 
silica and boracic acid were formed in small quantities, but 
when water was carefully excluded, these bodies did not 
appear; and the results were muriate of ammonia and silicated 
fluoric gas, or fluo-boric gas and azote. 
I ignited two points of charcoal intensely in fluo-boric and 
5?ilicated fluoric acid gases, pure, and mixed with oxygen; but 
no change, indicating a decomposition, took place ; the only 
new product was a little inflammable gas, which was probably 
disengaged from the charcoal. 
I passed pure liquid fluoric acid over charcoal ignited to white- 
ness, in a platinum tube ; no carbonic acid was formed, and a 
very minute quantity of gas only was produced, which proved 
to be hydrogen. 
I mentioned in my last communication to the Society, that 
I had made several experiments on the composition of the 
fluates; since that time I have repeated some of the processes, 
and I shall detail such of the results as appear to be most 
