THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[SIXTH SERIES.] 



JULY 1905. 



I. Osmotic Experiments on Mixtures of Alcohol 

 By P. S. Barlow, B.Sc. ( Vict,), St. John 

 Cambridge *. 



THE experimental work of this paper was undertaken by 

 way of examining a curious and unexpected result 

 obtained by S. U. Pickering f in an osmotic experiment with 

 propyl alcohol. The most recent estimate of the importance 

 of this experiment as bearing on the theory o£ the action of the 

 membrane in osmotic phenomena is given by W. C. D. 

 Whetham J. 



The following is a quotation taken from a letter written by 

 Pickering to ' Nature,' dealing with the hydrate theory of 

 solution §. It serves here the double purpose of describing 

 his experiment and giving his own estimate of its value in 

 supporting the hydrate theory. He writes : — " On the other 

 (the hydrate) side we have two experiments, which would 

 seem to be conclusive, but which the dissociationists have 

 hitherto thought fit to ignore. 



" Osmotic pressure, they hold, is due to the quasi-gaseous 



* Communicated bv Professor J. J. Thomson, F.R.S. 

 t Ber. Deut. Chem. (res. xxiv. p. 3639 (1891), and " Solution," Art. ii., 

 Watt's Diet, of Chem. 



X Whetham, ' Theory of Solution,' pp. 96, 97. 

 § Nature, lv. p. 223. 



Phil. Mag. S. 6. Vol. 10. No. 55. July 1905. B 



