' 129 ) 



Witli llic aid of the above data and puKiii^- />/,=37, 5 atmospheres 

 we find : 



/? = 0.0006 (nearly). 



The exi)erimcnt has yielded no more than about 0,00016 for this 

 value. So we have found it so many times too large, that for this 

 quantity the equation of state witii constant a and h cannot be con- 

 sidered to hold good even in approximation. 



From the well known equation : 



follows 



dp 



■),(-£)='■ 



With the values mentioned above and yielded by the experiment 

 we should therefore have for ether at 0° : 



273 X 0,001513 



1— ^ = 27 X 37,5 



0,00016 



or 



According to this equation v should be smaller than h which would 

 be absurd, if b does not vary with the volume. 



It we calculate the value of from then we find for ether 



/y = 0,0057 circa; in reality the liquid volume appears to be smal- 

 ler than /;. Dividing namely the molecular liquid volume by the nor- 

 mal molecular gas volume we find about 0,0047 ■). From this appears 

 coiu'incibly that the Aariability of b exists in reality and that thei*e- 

 fore an equation of state in wliicii (his varial)ility is not taken into 

 account, cannot possibly yield the data of the liquid state. 

 Let us return to the equation : 



, Ph Tk—T 

 — log- — f , 



P ^ 



which holds Ljood al least appi'oxiiualcly, as is coiitinnoil by Ihc 

 experiments, if w c lake ibr ƒ' a valu(» which is about twice as great 

 as would follow from llie o(pialion of state if we keep r^ and /> con- 



Ï) Continuitiit Slid Jvlitioii, p. 171. 

 ~) Conlinuiliit 2iid EUilion, p. 172. 



9* 



