74 K. D. Kraevitch on an Approximate Law of the 



Both modes of calculation give similar results for c — c x 

 and r . 



t. 



Pressures. 



t. 



Pressures. 



Calcu- 

 lated. 



Ob- 

 served. 





Calcu- 

 lated. 



Ob- 

 served. 





o 



20 



40 



60 .... 

 70 



185-18 

 42123 

 860-75 

 1189-0 



179-63 

 420-15 

 860-48 

 1189-4 



184-45 

 420-47 

 860-50 

 1189-4 



o 



90 

 110 



140 



21396 

 35979 

 7065-1 



2141-7 

 3594-0 

 6974-4 



2142-7 

 3603-6 



7077-8 



The irregularity in the sequence of the values of x caused 

 me to recalculate them through intervals of 10°: I then 

 obtained 



t 50° 60° 70° 80° 



x 3-0041 2-3514 2'2777 2-6131 



Here it is quite clear that the minimum lies between 60° 

 and 70°, and nearer to the latter temperature ; I take the 

 minimum as the arithmetical mean of 2*3514 and 2*2777, 

 and refer it to 65°. In this manner it was found that 



^=2*3146; 

 0-^ = 2*3146 x 4=0-07981. 



I calculated y for two temperatures 60° and 70°, and took 

 the arithmetical mean of the results. 



y*=3696-6; r =127*44. 



I again calculated the vapour-pressures from these new 

 values, the results are placed in the fourth column, they 

 roughly satisfy the results of experiment as well as the 

 figures in the second column do. 



Chloroform, CHC1 3 . 



17. 1st Method. 



t 25° 30° 60° 65° 70° 



x 5-769 5-423 3-6488 3-3996 $-8502 



t 75° 80° 85° 90° 100° 145° 



x 3-3630 3-3510 34282 3-5686 3-630 5-117 



x has a minimum at a temperature 70° to 80°, I take 75°, 

 and the arithmetical mean of the three figures corresponding 



