266 VINEGAR, CIDER, AND FRUIT-WINES. 



calcium chloride. The glacial acetic acid thus obtained contains 

 considerable hydrochloric acid, but can be readily freed from this 

 impurity by distilling over anhydrous sodium acetate, or, still 

 better, over anhydrous potassium acetate. As by this method 

 calcium chloride is obtained as a by-product (see p. 259), and 

 can be freed from all organic substances by glowing with the ac- 

 cess of air, the preparation of glacial acetic acid in this manner is 

 just as readily executed as, though it has no advantage over, 

 Melsen's process. 



Perfectly pure hydrated acetic acid dissolves oil of lemon in 

 every proportion, but if one drop of water be added a portion of 

 the oil immediately separates. This behavior may be utilized for 

 ascertaining at what moment the strongest acid is to be collected 

 at the last rectification. The pure but weaker acid obtained in 

 the fabrication is used in the preparation of pure acetates. 



Below 59.9 F. glacial acetic acid forms large, colorless, trans- 

 parent crystals, which above that temperature fuse to a thin color- 

 less liquid, of exceedingly pungent and well-known odor; it 

 raises blisters on the skin. It is miscible in all proportions with 

 water, alcohol, and ether, and dissolves camphor and several 

 resins. In a liquid state glacial acetic acid has a density of 1.063 

 and boils at 248 F. ; its vapor is inflammable. 



CHAPTER XXIII. 



ACETATES AXD THEIR MANUFACTURE. 



A CONSIDERABLE quantity of the vinegar obtained from alcohol 

 and wood (as well as the acetic acid prepared from it) is worked 

 into acetates, there being, for instance, factories which use their 

 entire product in the fabrication of lead acetate or sugar of lead. 

 Only the more important technical acetates (combinations of 

 acetic acid with metallic oxides, or, according to the view of 

 modern chemists, acetic acid in which 1 molecule of hydrogen is 

 replaced by a metal) will here be described. 



Acetic acid is a monobasic acid, i. c ., it contains 1 atom of 



