Variation in the Pressure of Saturated Vapours, 67 



extent they deserve confidence, I recalculated the observa- 

 tions through intervals of 10°. 



t 50° 60° 70° 80° 90° 100° 



x 3-6539 3-3633 2-4643* 2-5307 2-5271 2*6685 



The minimum value of x lies between 80° and 90°. But 

 as the values of x at these temperatures are nearly equal, it 

 is best to take their arithmetical mean and to take the cor- 

 responding temperature as 85°. We then have 



^=2*5289, 

 y 80 =3829-5, 

 y 90 =3803*4, 



the mean of «/ = 3816*5. 



The value now found for x is near to that given above, 

 and the values obtained for y by both methods can be con- 

 sidered as perfectly equal. The pressures calculated from 

 these new values of x and y are given in the fourth column 

 of the preceding table ; they differ but little from those in 

 the second column. 



Bisulphide of Carbon, CS 2 . 







12. 1st Method. 







t 10° 55° 70° 75° 80° 



85° 

 1-6515 



105° 



x 2-4771 1-7183 1-6498 i'6206 1-6398 



1-8626 



x has a minimum value 1*6206 at 75°. Hence 



0-^=1*6206 x |t =0*04265. 



According to Hirn, at 80° c— 0*25531 ; according to 

 Begnault Cl =0*15956 ; hence 0-^ = 0*09575. The latter 

 figure is more than twice that found above — the difference 

 is very considerable ; nevertheless there can be no serious 

 objection to such a discordance, for it has only to be 

 admitted that there is an aggregate error of 0*05 in the 

 specific heats, and the figures found for c — c x will both closely 

 agree. Conversely, calculating c x from c and x we find that 

 c 1= 0*21266 instead of 0*15956. 



According to equation (9) we find 



y = 3264-26, 

 whence 



r =3264-26x ^ =85-901. 

 7o 



* See Notes at end. 

 F2 



