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abnormal substances would then be tliose whose molecules can undergo 

 large variations in size. More suchlike questions arise — but 1 ^vill 

 no further (bscuss them without a closer investigation. 



P S T S C R I P T U M. 



When the above paper was printed I received a kind letter from 

 Dr. GisTAV Tkk'HNER, who informs me that he has sent me one of 

 his tubes filled with C Cl^ in which he has succeeded in strikingly 

 showing the large diUerences in deusily at I lie ciMlical tem|)erature 

 by means of floating glass spheres whose specific gravity has been 

 determined accurately. He himself however acknowledges emphatically : 

 "dass diese Erscheimmgen insofern keine Gleichgewichtszustande vor- 

 stellen, als die Phasen in Beridn-ung mit einander sicli aiisserst lang- 

 sam (beim Riihren sofoi-t) zu eiuer homogenen Mischung vereinigen." 



The equation of state deals only with states of equilibrium as I 

 have observed already before. Discussing these anomalies as I have 

 done in this pai)er, I treated questions which properly speaking lie 

 outside my subject. I have mentioned them, because I also expected 

 for a moment that the variability of h assumed by me, might account 

 for the slowly establishing of the state of equilibrium, lint this is 

 only the case if we assume, that the molecule does not immediately 

 assume the size which agrees with the \alue of T and r — and this 

 seems after all to be improbable to me, though I acknowledge that 

 molecular transformations occur which proceed slowly. The expectation 

 of Dr. Teichner, that the theory would lead to two really homo- 

 geneous phases is inaccurate in consequence of the action of gravity — 

 as has been shown already before i. a. by Gouy. Not the phenomenon 

 itself as it is seen, is anomalous, only the differences of the density 

 are anomalously large. It is true that Dr. Teichner writes to me 

 that he has ascertained that the temperature was constant but even a 



difference of temperature of ~-t degree yields a very considerable 



difference in density. For densities which are larger than the critical 

 one we have ; 



p dJ' 

 ê — being comparable to unity. If therefore in a point the tempe- 

 rature is degree too low, a diminishing of the pressure with 



100 



