0^' THE COMPOSITION OF BIRD-LIME. 25 



The alcohols separate as indistinctly crystalline, opaque matter, while 

 the resin forms a translucent, gammy deposit, still containing spirit, 

 on the bottom and sides of the vessel. The resin is redissolved in 

 spirit and tlie solution left to evaporate. Repeating these operations 

 several times yields it in a condition in which it shows no longer any 

 tendency to deposit crystalline matter. 



Separation and purißcatiou of the fattij acids. — By far the greater 

 part of the fatty salts remains dissolved when the saponified bird-lime 

 solution is poured into dilute spirit. The filtrate and washings from 

 the gelatinous precipitate of alcohols are diluted with water, mixed 

 with liydrochl(3ric acid, and warmed, in order to separate the fatty 

 acids. By similar and well-known methods the portions of these 

 acids precipitating with the bird-lime alcohols can Ije recovered, after 

 separating them as calcium salts from the alcohols and resinoïd body, 

 and added to the main quantity. The crude fatty acids which, when 

 cold, form a soft, brown, solid msss, are dissolved in alcoholic potash 

 and precipitated again with calcium chloride ; the calcium precipitate 

 is washed with spirit wliich removes chlorides and some colouring 

 matter, as well as some of the calcium salt of the soft fatty acid; the 

 precipitate is then washed with ether, which dissolves out, more 

 easily than the spirit, most of the remaining colouring matter and 

 calcium salt of the soft fatty acid ; lastly, it is heated with hydrochloric 

 acid and water, in order to get the crude palmitic acid. Repeating 

 these operations once or twice, and finally crystallising it from its 

 spirit-solution, gives the palmitic acid pure. The s[)irit and ether 

 washings of the calcium precipitate yield by appropriate treatment 

 the semiliquid acid, still in an impure condition. 



I'almitic acid can als(3 be prepared from bird-lime by destructive 

 distillation. Its purification from hydrocarbons by w\ay of saponifi- 

 cation, presents no great difficulty, and need not be described. 



