258 VINEGAR, CIDER, AND FRUIT-WINES. 



a fine dense powder, but as a gelatinous precipitate which settles 

 with difficulty and pertinaciously retains acetic acid. 



Finally, the lead acetate can also be decomposed by nitric acid, 

 this method having the advantage of yielding a valuable by-pro- 

 duct, lead nitrate. Christ! obtained from 100 parts of lead 

 acetate and 53 of nitric acid of 1.38 specific gravity, 65 parts of 

 acetic acid of 1.06 specific gravity and 80 parts of crystallized 

 lead nitrate. A weaker acid, for instance of 1.04 specific gravity, 

 can be obtained by dissolving the lead acetate in hot water, adding 

 the above-mentioned quantity of nitric acid, and after allowing the 

 greater portion of the lead nitrate to crystallize out, distilling the 

 mother-lye. To see whether the acid thus obtained is free from 

 nitric acid, compound a sample with a drop of very dilute solu- 

 tion of indigo and boil for some time : discoloration proves the 

 presence of nitric acid. 



Calcium acetate and sodium acetate form the basis for the 

 preparation of acetic acid on a large scale ; the former, if the 

 acid is to be used for ordinary technical purposes, where absolute 

 purity is not required, as, for instance, in the fabrication of lead 

 acetate, crystallized verdigris, aniline (from nitrobenzole and 

 metallic iron), etc., and the latter, if the acid is to be free from 

 empyreumatic odor and taste and suitable for use in the fabrica- 

 tion of aniline colors, for photographical, pharmaceutical, and 

 household purposes, etc. 



According to VolckePs method, for 100 pounds of dry yel- 

 lowish gray calcium .acetate 90 to 95 pounds of crude hydrochlo- 

 ric acid of 1.16 specific gravity are used, the acid obtained show- 

 ing a specific gravity of 1.058 to 1.061. By adding to the above 

 mixture 25 pounds of water distillation proceeds with greater 

 ease. 95 to 100 pounds of acid of 1.050 specific gravity being ob- 

 tained. In order to ascertain the required quantity of hydrochlo- 

 ric acid more accurately than is possible from the above-men- 

 tioned approximate statements, it is necessary to distill two small 

 samples of the thoroughly mixed acetate, for instance, 100 

 grammes, with 95 or 90 grammes of hydrochloric acid, and* to 

 test the distillate for hydrochloric acid. This is readily effected 

 by adding a few drops of dilute solution of nitrate of silver, a 

 white precipitate or white turbidity indicating hydrochloric acid. 



