MANUFACTURE OF WOOD-VINEGAR. 235 



the excess of the saturated solutions of hyposulphites, but soluble 

 in water and boiling alcohol. By boiling such a combination 

 with an alkaline carbonate, for instance, soda, it is decomposed. 

 If acetone is left standing over quicklime for some time, and 

 afterwards distilled, mesityle oxide C 6 H 10 O and phorone C 9 H 14 O 

 are formed ; the former is a colorless fluid smelling like pepper- 

 mint and boiling at 262 F., and the latter a crystallizable body 

 melting at 82.4 F. and boiling at 385 F. By heating acetone 

 with a little iodine and then adding alkaline solution until dis- 

 coloration takes place a lemon-color, crystalline precipitate of 

 iodoform soon forms. Methyl alcohol not showing this behavior, 

 this furnishes a means of recognizing a content of acetone in wood- 

 spirit. 



Determination of the Strength of Wood- Vinegar. 



C. Mohr gives the following method : Weigh off 10 grammes 

 of wood-vinegar, heat in a beaker with about 3 grammes of pure 

 barium carbonate until effervescence ceases, and filter. The solu- 

 tion of barium acetate is strongly colored, but the carbonate 

 remaining undissolved, very little. The residue after washing is 

 dried and weighed and the quantity of acetic acid present calcu- 

 lated ; each gramme of dissolved carbonate corresponding to 0.609 

 gramme of acetic anhydride or 10 grammes of wood- vinegar con- 

 tain 6.09 per cent. 



The quantity of undissolved carbonate can, however, be deter- 

 mined in a more simple manner by titration with normal nitric acid. 

 The latter is prepared by diluting commercial, pure, colorless, 

 nitric acid until an equal volume of it exactly saturates normal 

 sodium. Bring, for instance, 5 cubic centimetres of the commer- 

 cial acid into a beaker, add a few drops of litmus tincture, and 

 then by means of a burette normal soda lye until the color just 

 turns blue. If, for instance, 4 cubic centimetres have been 

 consumed, the 5 cubic centimetres of acid must be diluted to 40 

 cubic centimetres or 125 cubic centimetres to 1 liter. 



The undissolved residue of barium carbonate together with the 

 filter is now brought into a porcelain dish or beaker and a meas- 

 ured volume, for instance 20 cubic centimetres, together with 



