of Change of Condition on Vapour-pressure. 



67 



The vapour-pressures of solid benzene, determined by our 

 method, are given in the following Table. As Fischer's method 

 was statical, while ours is dynamical, a comparison of the 

 results of both is therefore given. 



Pressure. 



Temp. 



Pressure. 



Temp. 



Pressure. 



Temp. 







Series I. 





Series II. 





Serifs I. 





(cont.). 





(cont.). 





millim. 





millim. 



o 



millim. 



o 



35-9 



4-5-43 



21-8 



-095 



140 



- 7-02 



354 



5-21 



21-4 



-112 



13-25 



- 7-37 



35-2 



5 07 



21-0 



-1-45 



13-10 



- 7-53 



34-7 



4-89 



19-95 



-200 



1280 



- 8-42 



3115 



3-62 



190 



-2-54 



11-6 



- 8-77 



30-95 



3-32 



190 



-2-97 



11-2 



- 9-90 



29-15 



2-70 



18-05 



-2-98 



10-2 



- 9-72 



29-15 



2-75 



16-3 



-4-63 



101 



-1054 



28-7 



241 



16-25 



-5-45 



995 



-1103 



28-15 



221 



13-8 



-6-43 



7-35 



-14-12 



27-9 

 26-8 



1-99 

 1-29 



12-35 



-8-07 



Series III. 





26-7 

 26-65 



1-33 

 1-33 



Series II. 





14-25 

 140 



- 7-01 



- 7-70 



25-9 



0-85 



21-9 



-1-26 



10-4 



-11-2 



251 



064 



211 



-1-60 



10-2 



-110 



24-45 



0-23 



2005 



-261 



10-2 



-10-63 



24-0 



o-o 



18-75 



-3-08 



9-95 



-11-62 



23-9 



-003 



17-15 



-4-38 



9-3 



-11-92 



22-75 



-0-78 



15-2 



-5-78 



9-3 



-11-3 



22-2 



-0-91 



150 



-6-02 



87 



-1212 



For the first two series thermometers A and B were used ; 

 for Series III. another thermometer, D ; and it will be seen 

 that its readings confirm those of the other two. The indi- 

 vidual results are not so concordant as Fischer's. The 

 reason is that the volatilization of solid benzene is so quick 

 as to make it difficult to obtain an accurate reading before 

 the solid has volatilized and partially exposed the thermo- 

 meter-bulb. These numbers, near the melting-point, show 

 close concordance with those of Fischer, but at lower tem- 

 peratures they show signs of divergence. For example at 

 — 8*42, if Biot's formula be applied, the difference between 

 Fischer's results and ours amounts to 1*39 millim. ; and it is 

 evident, from the graphical representation, that the difference 

 would be an increasing one. It is to be noted that Biot's 

 formula agrees with Fischer's own results much better than 

 the formula employed by him. 



Our results were plotted on curve paper, and the constants 

 for a formula calculated from points on a curve drawn to 

 pass well through them. The constants are, for the formula 



F2 



