Vapour Pressure Equation. 659 



Benzene. 



Constants determined from temps. 20° C. and 80° C. 

 log 10 A' = 7-03208, B = 4286*3, for v in mm. 



Temp. C.... -10. 0. 10. 40. 60. 100. 288"5(crit.temp.> 



p mm. (obs.) ... 14'8 26"5 45"4 181 389 1344 48 atm. 

 p „ (calc.)... 15-5 27-3 45'9 179 384 1374 59 „ 



Ammonia. 

 Constants determined from temps. — 80° C. and — 33° C. 

 log 10 A' = 7*56507, B = 3229*5, for p in mm. 



Temp. C. ... -£0.-54.-33. 30. 60. 80. 100. 



p mm. (obs.) ... 35-2 240 761 3180 8700 19450 30800 46750 



p (equation 2)... 356 230 767 3460 10140 24280 39900 61990 



ja (equation 1)... „ „ 765 3200 8900 19300 29400 42000- 



Bromine. 



Constants determined from temps. 8°*2 C. and 58 c, 7 C. 



logi A' = 



= 7-0.37.i 



: (3, 



B = 



4029*5, 



for p in mm. 





Temp. C. ... 



-16-6. 





-12-0. 



-5-0. 



8-2. 16-9. 



.23-4 



p mm. (obs.) 



20 





30 



50 



100 150 



200 



p „ (calc.) 



27 





35 



52 



100 149 



199 



Temp. C 



40 5. 





51-9. 



58-7. 



302 (crit. temp.). 





p mm. (obs.) 



400 





600 



760 



131 atm* 





p ,, (calc.) 



396 





60 L 



760 



104 „ 





* A calculated value given in "Kaye & Laby." 

 Ether. 



Constants determined from temps. —10° C. and 40° C. 

 log 10 A' = 7-0300, B = 3731, for p in mm. 



Temp. C -10. 0. 10. 20. 40. 60. 80. 100. 



p mm. (obs.) 112 185 291 440 921 1734 2974 4855 



p „ (calc) 113 184 288 4"J8 929 1790 3200 5370 



Other liquids give similarly good results. Since A' alters 

 with the density, the constant B given in the tables may not 



