210 Analyses of Books, [March, 



of silicated fiuoric acid absorb 200 measures of ammoniacal gas. 

 Hence the resulting salt is composed of 



Ammonia 24'S3 



Silicated fluoric acid 75'\7 



100 



Or, very nearly of three parts by weight of acid, and one part of 

 ammonia. When dissolved in water, a portion of the silica is 

 separated, and subsilicated ammonia remains composed of 



Ammonia , . , , 26'53 



Acid 73-47 



100 



This last salt has a sharp taste, and crystallizes in four-sided 

 prisms. It is very soluble in v»^ater, but does not deliquesce. 

 When heated on glass or porcelain, it corrodes them, and seems 

 to reproduce silicated fluate : it is decomposed by the alkalies and 

 by sulphuric and muriatic acids. 



3. Fluate of ammonia may be obtained by decomposing sub- 

 silicated fluate of ammonia, by means of ammonia. It is 

 composed of 



Ammonia 7^-93 



Acid 27-07 



100 



This salt deliquesces. When heated, part of the ammonia is 

 driven off, and a subfluate of ammonia remains. Its fumes are 

 very dangerous when inhaled. When heated in a metallic vessel 

 it sublimes unaltered, but it corrodes glass and porcelain, and 

 combines with a portion of silica. 



4. Fluoboracic acid may be formed by heating in a retort a 

 mixture of one part by weight of fused boracic acid, two parts ot 

 fluor spar, and 12 parts of sulphuric acid. Its specific gravity is 

 2'370, that of air being 100; and 100 cubic inches of it weigh 

 72*31 grains. Waaler absorbs 700 times its bulk of this gas, and 

 forms a hea vy viscid acid, having considerable resemblance in ap- 

 pearance to sulphuric acid. Sulphuric acid absorbs 50 times its 

 bulk of this gas, and forms a very fuming, tenacious acid liquor, 

 Boracic acid decomposes silicated fluoric acid taking the place of 

 the silica. 



5. Fluoboracic acid combines in three proportions with am- 

 monia. 100 measures of the acid condense 100 measures, or 

 200 measures, or 300 measures of ammoniacal gas. The first of 

 these salts is solid, but the other two, though free from water, are 

 liquid and colourless. These salts are composed as follows : 



