402 Prof. R. Clausius on the Behaviour of Carbonic Acid 



In order to test the accordance of this formula with experi- 

 ment, I selected for comparison the three newer series of obser- 

 vations made by Andrews which relate to the temperatures 6°*5, 

 64°, and 100°, and three of the older series, referring to the 

 temperatures 13°*1, 31 0, 1, and 48 0, 1. In each of these series, 

 I selected for consideration, out of the volumes therein occur- 

 ring, a number which are distributed as equally as possible 

 over the entire interval of observation. I have, however, to 

 remark that Andrews has uot so expressed the volumes that 

 all the numbers have one and the same unit for a base, but 

 with each temperature he has taken as unit that volume which 

 the carbonic acid, under the pressure of one atmosphere, occu- 

 pies at that temperature. The volume thus expressed he de- 

 signates by e. In order to calculate from this the volume we 

 designate by v (which has for its fundamental unit the volume 

 occupied by the carbonic acid at the freezing-point under the 

 pressure of one atmosphere), we must know the coefficient of 

 expansion of carbonic acid under atmospheric pressure. For 

 this the value found by Regnault, 0*00371, and which Andrews 

 used in his calculations, is employed. 



The values thus obtained of v are, together with the respec- 

 tive temperatures, inserted in the formula, and then from these 

 the values of p belonging to them calculated. These values 

 are designated in the following Tables by "p (calc.);" and 

 below them are the corresponding observed values, designated 

 by " p (obs.)." A denotes the differences between the ob- 

 served and the calculated values of p. At each series it is 

 stated whether it belongs to the older or the newer series of 

 Andrews's observations. 



Table 1. — Temp. 6°*5 (newer series). 



6. 



1 



16-13* 



1 



29-62' 



1 



45-80' 



V 



0-06349 

 14-65 

 14-68 



- 003 



0-03458 

 24-63 



24-81 

 - 0-18 



0-02236 

 34-15 

 34-49 



- 0-34 



p (calc.) 



p (obs.) 



A 





Table II.— Temp. 13°*1 (older series). 



e. 



1 

 76-16' 



1 



80-43' 



1 



480-4' 



1 

 510-7' 





0-013768 

 47-98 

 47-50 



+ 0-48 



0-013037 

 49-27 

 48-76 



4- 0-51 



0-0021828 

 54-66 

 54-56 



4- 0-10 



0-0020532 

 74-96 

 90-43 



-15-47 



p (calc.) ... 

 p (obs.) ... 

 A 





