530 



Lord Rayleigh on the 



and the difference practically disappears at 95 per cent. 

 Indeed according to May 25 the vapour is a little the 



10 20 30 40 50 60 70 80 SO 100 



A. Alcohol and Water. B. Hydrochloric Acid and Water. C. Acetic Acid and Water. 



weaker at this point. The difference, however, is not to be 

 trusted, since the difficulties of manipulation, depending 

 partly upon the attraction of strong alcohol for aqueous 

 vapour, are much increased at this stage. It was these 

 difficulties and the uncertainty as to what exactly happened 

 with spirit stronger than 95 per cent, that retarded the pub- 

 lication of the work. I had intended to make further ex- 

 periments upon this point, but the matter was postponed from 

 time to time. The observations of Noyes and Warfel (/. c.) 



