Electrical Conductance in Absolute Ethyl Alcohol. 103 



seems to have escaped the notice of Goldschmidt, as he does not mention 

 either piece of work in any of his papers. 



In other words, the problem as undertaken by Goldschmidt is very 

 incomplete from this standpoint. No reason can be given why he 

 should use arbitrarily chosen limits for v in applying the Kohlrausch 

 formula, nor is it shown how accurately measured conductances up 

 to 20,000 liters dilution can be reconciled with such a falling-off in the 

 calculated A for the salt. 



Whether such a method could be applied or not, or whether another 

 can be substituted in its place, is a question of very great importance. 

 Furthermore, Goldschmidt based his conclusions on the results of 

 only six or seven salts. It was therefore deemed advisable by the 

 present writers, in the first place, to obtain more conductance data on a 

 larger number of salts, and, in the second place, to make these measure- 

 ments at several temperatures in order to look at this subject in a broad 

 way. 



EXPERIMENTAL. 

 REAGENTS. 



The alcohol used in this investigation was prepared in the following 

 manner: Ordinary 95 per cent ethyl alcohol was heated for several 

 days with lime in a copper tank with a glass condenser attached. A 

 minimum of refluxing in the condenser was obtained by inserting into 

 the tank through the stopper a coil of 3/16-inch lead-pipe containing 

 running water and serving to cause condensation immediately below 

 the reflux tube. The alcohol was distilled off, using a glass still-head 

 with a bulb blown in it and containing glass wool soaked in alcohol in 

 order to prevent any dusting over of the dry calcium hydroxide. The 

 middle fraction was treated in the same manner as above and again 

 fractionated. This process was continued until a specific gravity 

 of 0.78507 was obtained, the extreme limits of variation being 0.78505 

 to 0.78510, which, according to Circular No. 19 of the Bureau of Stand- 

 ards, corresponds to a purity of from 100 to 99.987 per cent. The 

 specific conductance of the alcohol varied with the different samples 

 from 0.46 to 1.6X10" 7 mhos. Upon the final distillation the alcohol 

 was collected in a 6-liter alcohol-extracted Jena bottle with a sealed 

 stopper carrying a siphon for drawing off the liquid, a calcium chloride- 

 soda lime tube, and an adapter with a ground-glass stopcock. Alcohol 

 prepared and stored in this manner, after several days following the 

 distillation, remained practically unchanged as to its conductance for 

 a period of several weeks. It was found that our discarded alcoholic 

 solutions and washings, when distilled once in a glass vessel with a few 

 drops of concentrated sulphuric acid before the final lime treatment, 

 produced a very superior grade of "absolute" alcohol, being generally 

 better than that obtained from fresh supplies of the 95 per cent material. 



