238 Scientific Proceedings, Royal Dublin Society. 



throughout the experiment by adding water at the same rate as the solution 

 distilled over. The distillate was collected in approximately equal fractions of 

 5 or 10 grams. The distillation was carried out at the approximate rate of 

 60 e.e. per hour. It was found convenient to employ a set of receivers, which 

 were weighed and provided with stoppers. Before a distillation the cylinders 

 were thoroughly cleaned with a solution of chromic acid in concentrated 

 sulphuric acid, and finally washed several times with distilled water. They 

 were then drained by inverting them in a clean beaker. Immediately after a 

 fraction had been collected, the cylinder was removed and stoppered until a 

 determination of the alcohol could be carried out. 



The Alcohols investigated. 



The alcohols were carefully purified by repeated fractionation, and usually 

 a fraction boiling within 0'2° was reserved. 



Methyl Alcohol was obtained from the purest commercial methyl alcohol 

 free from acetone and ethyl alcohol. A sample was collected after two 

 fractionations from an eight-section " Young evapoi'ator fractionating 

 column." It boiled at 64-4-64-6° at 759 mm. pressure. Density = 0-7965 

 at 15-5/15-5°. 



Ethyl Alcohol was purified by refluxing over solid potassium hydroxide, 

 then over freshly ignited quicklime, and finally over calcium. On fractiona- 

 tion the alcohol was obtained of density 0-7937 at 15-5/15'5° and boiling at 

 78-3-78-47761 mm. 



n-Propyl Alcohol was obtained from fusel oil by repeated fractionation. The 

 distillate collected between 97 and 97'5° 760 mm. was reserved for the deter- 

 mination of the distillation constant. Although a considerable quantity of 

 fusel oil was fractionated, using both a Young column and a long fi'actionating 

 column with Lessing rings (copper), only a very small proportion of alcohol 

 with a boiling point 97-2/763 mm. and density 0-8078 at 15-5/15-5° was 

 obtained. The purity of this alcohol is probably not of the same order as in 

 the case of the other alcohols examined. 



n-Butyl Alcohol was obtained by fermentation, and after drying it 

 thoroughly over quicklime and potassium carbonate, it was fractionally 

 distilled several times — until the density showed no alteration on further 

 treatment. Boiling point = 117-67760 mm. ; density = 0-8137 at 15-5/15-5°. 



sec-Butyl Alcohol was obtained from «-butyl alcohol. The normal alcohol 

 was converted into j3-butylene, which was absorbed by moderately concen- 

 trated sulphuric acid under pressure yielding sec-butyl hydrogen sulphate. 

 The alcohol was obtained by hydrolysis, and was purified by drying and 



