( 128 ) 

 Let us take again p to l)e so SDiall that we may ^v^ite 



-^ (ü - ^>) = RT. 

 From this we may deduce: 



1= "Ty. X^-2 (3) 



T V 



For — - = 0,585 (Ether at 0^) is equal to 4,7 as appears from : 



it V — b 



8 T \b 



27 7^j 



0' 



I' 

 With this value — - = 4,7 we tiiid -. 



V — b 



T/dv\ _ 1 



So we liud for the eoefïieient of dilatation under low pressure 



and at this temperature which is so low that we may neglect the 



pressure, the value: 



1 /'dü\ 0,00367 

 — — =- = 0,00180. 



Comparing tliis Aalue witii that which the experiment has yielded 



and which we may j)ur at 0,001513, we see that it may be used 



at least as an approximated \aliie. 



1 /di-\ 

 The above equation (3) yields for — ^ ^vith r ^ 2 A an 



T 27 

 infinite value and so 777- = — • This quite agrees witli the circumstance 



1 X; 32 



T 21 

 that the isothermal for — = — touches the T -axis and it warns us 



Tic 32 



that equation (3) cannot yield any but approximated ^-alues for much 



lower values of T. 



f "^ A 

 For the coefficient of compressibility ^ namely — — in that 



\vdpjT 



same liquid state we find 



'dp\ RTv^ 2a 



or 



\dv^jT {^\~ W ^'i^ ^'i^V'i — ^ 



i^27;,/AYr^_, 



^ V'l/ V^i— ^ 



