436 



Prof. J, Dewar and Mr. H. 0. Jones. 



[Mar. 3, 



by Mond and Nasini, viz., the boiling point 43° C. 751 mm. and 

 the pressure at 20° C. 338*7 mm., a similar expression, log p = 7*281 

 - 1392/T, is obtained. 



Taking Mittasch's pressures for 2° C. and 40° C. the Rankine 

 obtained is : — 



\ogp = 7-781 - 1555-7/T. 



The boiling points calculated from these formulae are given below : — 



Mond 43°*3C. 



Mittasch 44° * 4 



Dewar and Jones 43° * 2 



In order to further confirm our vapour-pressure determinations, we 

 made a determination of the boiling point of some carefully dried and 

 redistilled nickel carbonyl. With the barometer at 769 mm. the 

 liquid boiled at 43°*2 - 43°*33 C. 



It would therefore appear that our vapour tension curve is the 

 more accurate. The following curves, fig. 2, illustrate very clearly 

 the extent of the deviations at different temperatures. 



80 Q 1 : 1 1 1 1 



~/o°C o° 7o° 20° 30° ~40° 50 c 



Temperature. 



Fig. 2. 



