1824.] M. Berzelius on Fluoric Acid. 455 



and found the constituents in them all to be combined in similar 

 proportions. I believe, therefore, we may conclude, that all the 

 double salts obtained by saturating bases with this acid possess an 

 analogous constitution. I shall here state the details of these 

 analyses. The analyses of the salts of soda and barytes are the 

 most easily executed, and afford the most decisive results. 



Silicaled Filiate of Soda. — a. 100 parts, decomposed by sul- 

 phuric acid, gave 74*85 parts of sulphate of soda = 32*844 parts 

 of soda. The sulphate of soda dissolved in water without leav- 

 ing any residue, and was exactly neutral, b. 100 parts dissolved 

 in boiling water were slightly supersaturated with carbonate of 

 soda, and the liquid was mixed with an excess of a solution of 

 carbonate of zinc in ammonia. The whole was now evaporated 

 until the ammonia was expelled, and the silica was separated in 

 the manner which has been already described. It weighed, 

 after being ignited, 31-6. c. The filtered alkaline liquid was 

 evaporated nearly to dryness ; the excess of carbonate of soda 

 was saturated with acetic acid, and the acetate of soda was 

 separated by alcohol. The fluate of soda, isolated by this 

 means, weighed, after ignition, 134 parts. As 32*844 of soda is 

 equivalent to 44*2 of neutral fluate of soda, and as 44*2 X 3 = 

 132*6, it follows that in the double salt the soda is associated 

 with thrice as much fluoric acid as is reo,uisite for its neutraliza- 

 tion. It is impossible by this analytical process to separate the 

 silica completely; hence the quantity indicated by the experi- 

 mental result is always rather less than the truth, while, on the 

 contrary, that of the fluate of soda is slightly in excess. 



Silicatedjluatc of barytes, when ignited in a glass retort, gives 

 a trace of the sublimate already mentioned, which consists of 

 water supersaturated with the acid gas. The expelled gas does 

 not corrode glass, and therefore contains no disengaged fluoric 

 acid. a. 100 parts of the salt, in two successive experiments, 

 left, after ignition, 62*25, and 62*26 parts of fluate of barytes. 

 Consequently the fluate of silica which, had been expelled, 

 amounted to from 37*74 to 37*75 parts, b. 100 parts, decom- 

 posed by sulphuric acid, gave 82*933 parts of ignited sulphate 

 of barytes. 



Silicaled Fluate ofPolasli. — 100 parts were converted by sul- 

 phuric acid into 78*85 parts of sulphate of potash = 42*634 

 potash. 



Si Heated Fluate of Lime. — 100 parts gave with sulphuric acid 

 63*69 parts of sulphate of lime ; and by strong ignition, 36*2 

 parts of fluate of lime. Both these quantities represent 26*4 

 parts of fluate of lime. 100 parts were incorporated with 600 

 parts of oxide of lead, covered with an equal quantity of the 

 oxide, and exposed to a low red heat. The mixture fused, and 

 gave off 16*25 parts of water. Consequently this salt contains 



