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



t 50° 55° 60° 



r 60-752 60-616 60-470 



0136 0-143 



c-c Y 0-0272 0-0286 



The arithmetical mean for c— c x will be 0*0279 and for 

 r 60*616; both figures are similar to those given above by 

 the 1st method. 



t. 



Pressures. 



t. 



Pressures. 











Calculated. 



Observed. 





Calculated. 



Observed. 



o 



-20 



62-61 



59-16 



o 

 60 



1511-9 



1511-9 



10 



258-66 



257*40 



80 



2639-4 



2638-6 



30 



564-77 



564-51 



110 



5414-5 



5394-0 



50 



1112-8 



1112-8 



140 



9923-4 



9779-0 



Ethyl Alcohol, C 2 H 6 0. 



20. 1st Method. 



75° 

 4-9002 



135° 

 7-9917 



105° 

 6-7194 



140° 

 8-5192 



120° 

 7-3370 



145° 

 8-6407 



125° 

 7-7770 



150° 

 8-6754 



130° 



7*9890 



The value of x gradually rises from a lower to a higher 

 temperature. However, on examining the curve of #'s it 

 may be remarked that, notwithstanding its irregularity, it 

 strives to attain a maximum, which lies about 150° or slightly 

 higher. We assume that 150° corresponds to the maximum 

 value of x, i. e. to 8*6754. Acting thus, we cannot naturally 

 expect to obtain exact results. We shall have 



6-^ = 8*6754 x-^ =0*3772. 

 1 46 



According to Hirn c 150 = 1*0503, and according to Regnault 

 ^ = 0*4797; hence the experimental value of c— c 1 =0 , 5706. 

 By equation (9) we find 



z/ = 4399*9; 



hence r Q = 191*30. 



According to Regnault's formula it is 170*5. 



