802 Mr. F. B. Young on the 



D 



graduated in tenths of a degree and was calibrated by 

 means of a similar Reichsanstalt thermometer. The boiling- 

 point of the selected fraction was 34°-53-34°'54 C. (N.T.P. 

 at lat. 45°). 



The B.P. is lower than the generally accepted value 

 (34°'6 C.) ; but, according to Wade and Finnemore (8), 

 whose work on the purification of ether was unfortunately 

 not published until after the above preparation had been 

 completed, the boiling-point of pure ether is very near 

 34°'50 C, and the ether prepared was therefore not really 

 freed from the last traces of alcohol. This possibility is 

 remembered in discussing the experimental results obtained. 



The following are details of the various tubes to which 

 reference has been or will be made in this paper : — 



Tube VII. was filled with ether kindly supplied by 

 Mr. Usher and prepared in the manner described by Travers 

 and Usher (7); it had, however, been kept for some time. 

 The tube was filled with the aid of liquid air and the simple 

 Topler pump, the ether being frozen seven times ; it was 

 sealed with the vapour issuing. 



Tube XII. was rilled with ether freshly prepared by the 

 method of Travers and Usher (7), sodium and potassium 

 alloy, however, being substituted for potassium wire. It was 

 filled in the same way as tube VII., the ether being frozen four 

 times. 



Tube XIII. was filled with Kahlbauin's ether treated with 

 sodium and potassium alloy. It was filled by means of the 

 special apparatus described and sealed whilst the vapour was 

 issuing. 



Tube XIV. was filled in the same manner and at the same 

 time as tube XIII., but was sealed whilst the ether was frozen. 



For purposes of comparison, tubes VII., XII., XIII., and 

 XIV. were fastened side by side and immersed in a tank of 

 water at a temperature of about 10° C. After immersion for 

 about 15 minutes, the bell-tubes were filled simultaneously 

 by inversion of the experimental tubes, and observations 

 were made of the condensation of the vapour carried down 

 by the bells. Tubes XIII. and XIV. were markedly superior 

 to tubes VII. and XII., whilst XIV. was distinctly freer 

 from permanent gas than XIII. The observations are tabu- 

 lated in Table I. " 



It may be mentioned that the head of liquid under which 

 the vapour condensed was roughly the same except in the 

 case of tube XIL, in which it was about one-half as great as in 

 the other tubes. Hence the apparent similarity of tubes VII. 

 and XIL implies that tube XII. is somewhat superior to 



