( 332 ) 



of the density of carbonic acid we should find for the mixture '/2 

 hydrogen — Vj carbonic 1,00158, whence: 



y = 0.99950 + 0,00136 (1— ,r) + 0,00560 {l—xf . 



From the point of view of a consistent application of VAN der 

 Waals's law a calculation of the theoretically normal volume of 

 the carbonic acid from the normal volume and the compressibility 

 would be preferable to the method of calculation followed by me. 

 But then the proportion of the weights of one volume of carbonic 

 acid and hydrogen in the state of perfect gases and the molecular 

 weights would be discordant, and it are the latter which we want as a 

 basis for our choice of units of volume (with a view to v. d. Waals's 

 theory of mixtures). The influence of the differences yielded by the 

 calculations from the different data is not such as to render doubtful 

 the character of the change of pressure when substitution takes place, 

 but still in my determinations the discrepancies differ little from the 

 errors of observation. From this we see once more the necessity of 

 accurate observations with perfectly pure substances in order to make 

 progress in the knowledge of the laws which govern the gaseous state. 



TABLE VI. .r = 0,3528. 



TABLE VIL .T = 0,4993. 



Volume 



0,0 



Pu°-V) 



2810 i 34.441 36.85 



2585 1 37.17 



I 

 2442 j 39.15 



2299 41.38 



2159 

 2014 

 1869 



1724 



43.77 

 46 54 

 49.70 

 53.35 



39.80 

 41.96 

 44.38 

 46.95 

 49.99 

 53.45 

 57.40 



15S7 1 57.351 61,80 



1480 

 1340 

 J207 

 1067 

 09255 



60.90, 65.75 



71.75 

 78.45 



66.35 



72.40 



80.3(ii 87.25 

 ^ 89.90 98.30 

 07940:101.60112.0 

 06510115.3 I 



1889 

 1736 

 1624 

 1468 

 1323 

 1172 

 1017 

 08694 



52.36 

 56.80 

 60.45 

 66.35 

 73.05 

 81.85 

 93.15 

 107.3 



55.50 

 00.20 

 64.05 

 70.40 

 77.65 

 87.10 

 99.50 

 114.9 



