( 666 ) 



We find then: 



f/, = 1.010595 instead of tk = 1 



t> t = 1.0379 „ „ * k '=l 



Pi = 1.06566 „ „ P fc = l. 

 Tlie isotherms from which V. s. 1 has been derived by the com- 

 putation of the virial coefficients $, @ etc. (See comm. N°. 71, These 

 Proc. June 1901), indicate therefore, by means of interpolation 

 according to this mode of calculation, a critical state, which, drawn 

 in the ^-diagram, has shifted with respect to that which was found 

 by immediate observation ; the critical temperature according to V. 

 s. 1 is namely tk Tk when Tk is the observed critical temperature. 

 So are also the values found for p max ., *tiq and D wa/ ,. at t by the 

 application of Maxwell's criterion, different from those which we 

 should find when dividing p max , by pk, vu q . and v oa/ >. by r /c . The 

 deviations are of the same order as the deviations of the substances 

 inter se, when they are compared by the law of the corresponding- 

 states. At t = 0,9 they are about zero, but they increase as we 

 approach the critical state, so that the deviations agree with a gradual 

 transformation of the net of isotherms. The following table gives a 

 survey of the deviations in the corresponding values. 



Column A refers to V.s. 1 and implicitly to />/„ Tk of CO a 

 B ,, ,, the observations ,, CO, 



r NO 



In the neighbourhood of the critical temperature the phenomena 

 are governed by the difference of the temperature of observation and 

 the critical temperature, T — Tk; for this reason we have chosen 

 for the detailed model of 26° such a temperature T for the com- 



