BAILEY. | Methods of Analysis. 89 
used for the determination of bromin, iodin, and boric acid. 
The residue is treated with hydrochloric acid, evaporated to 
dryness, as in the separation of silica, and the insoluble residue 
is filtered off. Call this filtrate ‘solution B.’ The residue last 
mentioned is heated with hydrofluoric acid to expel silica, and 
then fused with sodium carbonate. The fused mass is. dis- 
solved in water, and the precipitate, which would contain the 
barium and strontium as carbonates, is dissolved in hydro- 
chloric acid and added to solution B. This solution, with so- 
lution B, is treated with sulfuric acid to precipitate the sulfates 
of barium and strontium, the precipitate is ignited and fused 
with sodium carbonate, digested with water, and filtered. The 
insoluble part is treated with acetic acid, and in this solution 
the barium is precipitated with potassium chromate. This pre- 
cipitate, after being filtered off, is digested with sulfuric acid, 
and finally weighed as bariwm sulfate. The filtrate from the 
barium chromate is digested with ammonium carbonate, and 
the strontium carbonate, with a little calcium carbonate, is 
filtered off. This precipitate is dissolved in nitric acid and 
evaporated to dryness in a weighed platinum dish. The solid 
residue thus obtained is digested with a mixture of equal parts 
of absolute alcohol and ether, which will dissolve the calcium 
nitrate without having any appreciable action on the strontium 
nitrate. Weigh the residue as strontium nitrate in the platinum 
dish. Test all the residues with the spectroscope.’’ 
For the determination of Boric Acid, an excellent method is 
that suggested by Gooch.* In this process the dried salts are 
treated in a retort of special construction, which can be heated 
in a parafine bath, with acetic acid and methyl alcohol, and 
the latter on being distilled off carries with it the boric acid. 
This acid is then caught in a known weight of calcium hydrate, 
and after the operation the calcium oxide is heated and deter- 
mined. The increase in weight of the lime is due to the boric 
anhydrid (B,O,) that has been absorbed. 
For the determination of Fluorin,” a large quantity of the 
34, Am. Chem., Jour., IX, 23 ; also, Cairns’s Quant. Anal., p. 299. 
35. Cairns’s Quant. Anal., p. 301. 
