( S07 ) 



the difference of the radii of curvature of the tops of the bounding 

 menisci exceeds that between 3 and 5 mm. 



At those temperatures for which 6 max <J - — \- L 6 C(Xjl , the phenome- 

 non of the phase which is uppermost at low pressure, sinking and 

 rising again does not make its appearance in consequence of gravity 

 alone. If this condition is satisfied for mixtures of a definite pair 

 of substances for every temperature between the lower and the 

 higher barotropic limiting temperature, the phenomenon could only 

 be realised for these mixtures by the aid of a suitable stirrer. 



§ 5. Remarks on further experiments with helium and hydrogen. 



a. In the experiments mentioned in Comm. N°. 96" the gas phase 

 proved to remain below on compression to the highest pressure which 

 the apparatus will allow. When we repeat these experiments at a 

 higher temperature (which may e. g. be obtained by boiling the 

 hydrogen of the bath under higher pressure 1 )) it is to be expected 

 that the barotropic pressure will first rise, as in the beginning starting 

 from — 253 d the gas phase will continue to expand more strongly 

 than the liquid phase. At higher temperature the liquid phase begins 

 to expand more strongly than the gas phase, but the mutual solu- 

 bility plays already such an important role then that a definite expectation 

 cannot be expressed, unless this, that on account of the retreating 

 of the plait and the impossibility of the barotropic tangent-chord to 

 reach the side of the hydrogen, the higher barotropic limiting tem- 

 perature may be pretty soon reached. Also in connection with the 

 estimation, which may be made from this concerning TtHe, it will 

 be of importance to investigate whether with a suitable concentration and 

 at a suitable higher temperature we may observe the liquid phase sinking 

 after it had first risen. That the phenomena at higher temperature, 

 if the glass tube used should prove strong enough to bear the pres- 

 sure, should be prevented by capillary action, is not probable, as 

 capillarity together with the differences of density decreases at higher 

 temperature; moreover in spite of capillarity the phenomena might 

 be realised by the aid of a suitable stirrer. 



b. With decrease of temperature the limit is soon reached at 

 which we meet with the solid phase. The question rises whether 

 then the phenomenon : the solid phase, (the solid hydrogen) floating 

 on the gas phase (chiefly the as yet still gaslike helium), might not 

 be realised. 



l ) Or by using the vapour from boiling hydrogen in a separate vessel [added 

 in the translation]. 



