gg FLUORIC ACID. 



24 '5 ammonia 

 7 5' 5 acid 



100-0 

 Silicated fluat of ammonia volatilizes unaltered, if heated by a 

 spirit-lamp in the vessel in which it is formed, and provided 

 * moisture be entirely excluded. 

 Water decom- Ljfce silicated fluoric acid gas itself, this salt is decomposed by 

 pound and " water, and a similar precipitation of silex occurs, and in tho 

 precipitates same proportion. Thus the salt formed by the union of 30 

 cubic inches of silicated fluoric gas, and 60 of volatile alkali 

 (barom 30, therm. 60) in a small glass jar over mercury, 

 being carefully collected and introduced into water, afforded 

 five grains of pure silex, weighed after being well washed and 

 heated to redness. 

 The aqueous The saline solution, since part of the silex of the silicated 

 Skated fluat " ^ uo " c acic * & as IS se P arate d during its production, appears to 

 of silex and be a subsilicated fluat, or a combination of subsilicated fluoric 

 oma * acid and ammonia. Another mode of making it, more directly 

 proves that this is its composition. When ammonia is added to 

 the subsilicated fluoric acid in excess, this salt is formed with- 

 out any precipitation. From these facts, it may be concluded, 

 that independent of water, which appears to be essential to its 

 existence, 100 parts of it consist of 



28*34 ammonia 

 71-66 acid 



100-00 



It has a pun- Subsilicated fluat of ammonia has a pungent saline taste. It 



?eddens S litmus;J ust perceptibly reddens litmus paper. Slowly evaporated, it 



crystallizes not forms small transparent and brilliant crystals. The largest I 



cor^e^glass could obtain » appeared to be tetrahedral prisms. The solid salt 



whilehot,&c. is very soluble in water j but is not deliquescent. When heated 



it appears to sublime unaltered. It is curious that the solution 



of this salt, when evaporated by a heat near its boiling point, 



powerfully erodes the glass or porcelain vessel, and a residuum 



of silex appears, on the addition of water, to re-dissolve the 



salt. This erosion and residue of silex I have seen produced three 



times following, with the same quantity of salt. I mention the 



fact, 



