832 Proceedings of Royal Society of Edinburgh. [sess. 
The following way has been found to give good results: — A 
quantity of dry acid and an excess of absolute alcohol are placed 
in a round-bottomed flask, provided with an efficient fractionating 
column and a tap -funnel ; 1 cc. of alcoholic solution of hydrochloric 
acid is added, and the mixture boiled for 20-30 minutes. 
The fractionating column (Young’s rod and disc pattern, with 
seventeen discs and contractions on the tube) serves as a reflex 
condenser. A quantity of benzen, sufficient to remove one-quarter 
of the total quantity of water produced by the reaction, is then run 
in and the ternary mixture slowly distilled off. As soon as all the 
benzen has come over, the distillation stops, and the residue boils 
under reflex condenser as before until a further quantity of 
benzen is added.* This process is repeated three times, and 
finally the excess of alcohol is boiled off, and the residue purified 
by distillation in the usual manner. As the ternary mixture, 
according to Young, contains 1 8*5 per cent, of alcohol, 7 ‘4 percent, 
of water, and 74T per cent, of benzen by weight, each gram of 
water requires 10 gm. (1Y5 gc.) of benzen. In practice, 10-15 
per cent, excess of benzen was added. In the experiment described 
in detail below an additional 5 cc. of benzen was added ; the result 
showed that it was unnecessary. 
As an illustration, one experiment will be described in full ; in 
the others the quantities and yield only will be given. 
Diethyl tartrate. 
30 gm. tartaric acid, 
80 cc. ethyl alcohol, 
1 cc. alcoholic hydrochloric acid, 
boiled under reflex condenser for 30 minutes. 
Added 25 cc. benzen + 5 cc. alcohol. 
10.30 a.m. temp. 64’8° C. 
11.0 ,, „ 66*2° C., distillate 29 cc. 
25 cc. benzen + 5 cc. alcohol. 
11.25 ,, „ 67‘8° C., distillate 35 cc. 
25 cc. benzen + 5 alcohol. 
12.5 p.m. temp. 65 *0° C. 
.10 ,, ,, 66 -7° C , distillate 35 cc. 
* This circumstance is one of the causes which make the process so convenient. 
