250 VINEGAR, CIDER, AND FRUIT- WINES. 



carbons, which can be readily ascertained by mixing the sample 

 with water ; further to the presence of acetone, methyl acetate, 

 and ordinary alcohol, the latter being sometimes found as an 

 adulteration. The presence of acetone is recognized by the 

 colorless crystalline precipitate formed on shaking with a satu- 

 rated solution of sodium hyposulphite. The presence of methyl 

 acetate is shown when, by boiling the wood-spirit with soda lye 

 and subsequent distilling off, a residue remains in which acetic 

 acid can be found. Ordinary alcohol can be detected by distill- 

 ing the wood-spirit with double to four times its volume of con- 

 centrated sulphuric acid. By the action of the latter upon the 

 wood spirit dimethyl ether (CH^O is formed ; but by the action of 

 the excess of sulphuric acid upon alcohol, cthene C 2 H 4 . The 

 first is readily soluble in water, 1 volume of the latter dissolving 

 37 volumes of the gas ; the latter, however, dissolves with diffi- 

 culty, 7 volumes of water absorbing only about 1 volume of it. 

 Hence, if alcohol be present in the wood-spirit, ethene will remain 

 by shaking the gas mixture with its equal volume of water. By 

 adding bromide ethene dibromide, C 2 H 4 Br 2 , a colorless oily liquid, 

 having a sweetish smell and taste, is formed. 



Yield of Charcoal, Wood- Vinegar, and Wood-Spirit, as well as of 



'Tar. 



The statements as to the obtainable yield of products resulting 

 from the distillation of wood vary very much, which is but 

 natural, as the yield depends on many factors : on the variety of 

 the wood, its age, even on the soil upon which it is grown, the 

 time it has been stored, on the degree of dryness, the dimensions, 

 the position of the retorts, the degrees of temperature, and espe- 

 cially on the duration of carbonization. 



Stoltze, in 1820, published experiments, made with the greatest 

 care, to show the amount and strength of the products obtained 

 from the distillation of several varieties of wood. The quantity of 

 each kind of wood submitted to destructive distillation was one 

 pound, a quantity suitable, in the generality of cases, to form a 

 precedent for the manufacturer on the large scale. The woods 

 were all collected at the same time of the year (towards the end 



