16,6 CHYMISTRY APPLIED TO AGRICULTURE. 



The acid procured in this manner has some very great 

 advantages over that obtained by the acidification of fer- 

 mented liquors ; this, being distilled, is consequently puri- 

 fied from any foreign substance, and can be thrown into 

 the market in so concentrated a state, as to render it 

 much more active than vinegar of vvrine, and capable of 

 producing effects which it is difficult to obtain from that. 



Even to the present day, all the acetic acid employed 

 either for domestic purposes, or in the numerous opera- 

 tions carried on in the workshops of the various arts, has 

 been provided by the degeneration or decomposition of 

 fermented drinks, such as wine, beer, cider, perry, &bc. : 

 all these liquors are more or less spirituous, and contain a 

 portion of mucilage, which tends continually to produce in 

 them the acetous fermentation. 



To prevent the acidification of wine, the liquor should 

 be put up in good casks, well stopped, and placed in a cool 

 place, of which the temperature does not sensibly vary; 



tubes into the fire-place, to heat the cylinder and increase the carbo- 

 nization. 



The process of carbonization lasts five hours ; the cooling is com- 

 pleted in about seven. 



The acid thus produced is very impure, but serves for the prepara- 

 tion of pyrolignites of iron : in order to purify it, it must bt put into an 

 iron boiler, saturated while cold with chalk, and the tar, which will rise 

 to the top, skimmed off; the liquor must then be poured into another 

 boiler, heated to ebullition, and the saturation continued up to this 

 point; sulphate of soda is afterward added, when there is formed 

 sulphate of lime, which is precipitated, and acetate of soda, which 

 remains in solution. The liquor must then be drawn off and evapo- . 

 rated till pellicles are formed, when it is thrown into large tubs, where 

 it acquires solidity by Cooling. 



An igneous fusion of this mass has been produced by heating it 

 in a cast-iron boiler, till the water was all evaporated, and afterwards 

 continuing the fusion to ignition ; the liquor was then poured into 

 moulds in which it solidified ; in this state it is black, and easily 

 soluble in hot water : a solution of it well filtrated and evaporated 

 yields crystals of acetate of soda, which retain almost nothing of the 

 empyreumatic odor. When these crystals are dissolved in water, and 

 the solution decomposed by sulphuric acid, crystals of sulphate of 

 soda are obtained, and acetic acid, which only requires distillation to 

 be perfectly pure ; the acid then marks from eight to ten degrees of 

 the aerometer of Baume, ( = specific gravity of 1.060 to 1.075.) To 

 obtain the acid in a crystalline state, it is sufficient to combine it 

 with lime, and to decompose by sulphuric acid this salt slightly cal- 

 cined : the sulphate of lime takes nearly all the water which re- 

 mains in the acetate. 



The mother water of the first operations, evaporated to dryness and 

 mixed with tar, serves as a combustible ; the ashes passed through a 

 reverberatorv furnace and afterwards leached affords very fine sub- 

 earbonate of^soda. 



