( 201 ) 



for l)v iiiconipletc ('Oiiibiiuitioii of llio Iwo coiïiponeiils, so lli;il ;i 

 siiuill (iiuiiilily of water escapes rtii-lln>r aclioii ol" (lie gas by Ueiiig 

 enveloped in solid hydrale. A ruriiici- pioof of this is fiiniislied by 

 the fact that some |)reliniiiiaiT experiments, in wlrcli little care was 

 devoted to the com[)lete formation of the hydrale by siiaking, yielded 

 far more oscillating- values, which were all higher than those men- 

 tioned above. So it is beyond doubt that tlie values found can only 

 indicate a too great content of water. 



So the hydi-ate H^S . 5 HJ) diifers from the many hydrates 

 M.(j/I.,0 examined by Villahd. 



3. When in conclusion we survey the results of ihe imestigation, 

 it appears that the system H,S — H^O presents great analogy to the 

 system SO, — H.2O, one of the gashydrate systems investigated by 

 Bakhuis Roozeboom. The sohdulity of the hydrate of SO.^ under the 

 three-phase pressure in the condensed gas is oidy small, like that 

 of the hydrate of N.,S, because in both eases the pressure of the 

 line SLJjr lies ojdy little lower than the vapoui- tension line of the 

 li(|uid, most volatile compcment. The other systems examined by 

 Bakhuis Roozeboom deviate more or less from this system, either in 

 consequence of the fact that the concentration of L^ on SL^G lies 

 much less on one side, or because this line shows higher pressure 

 than the two components, so that the L-6r-surface presents a nuixi- 

 mum in the isothermal sections. 



Anorij. Chon. hthoiuilorn of tlw IJiiicersih/ of Ainslerddin. 



Physics. — 'UJti iJw, mconslstciicii if nii/ ltc((t. thcorcni and VAX dkr 

 Waals' lyiitiiion dt renj low tenipcrdf.iurs.'' By Prof W. 

 Nkknst of Berlin. (Communicated by Pi-of. \\. A. Lokkntz). 

 (Communicated at tlio meeting of May 27, 1911.) 



Messrs. Kohnstamm and ( )rnstkin ') have published a criticism on 

 my theorem of heat -■) in these Proceedings, which is based on clearlv 

 mistaken premises, and which therefore calls for a refutation. 



Everybody who has studied Thermodynamics, knows the form, 

 in which Hki.mholtz and others have expressed the second theorem 

 of heat : 



dA 



dT ^ ' 



1) These Proc. of' 24 Dec. 1!)10. 



-) Ni;uNST, Theoret. Clieni. VI Anil. 8. G'.l!» (IHOU); d'. also tlie lilciatiiie 

 mentioned in my paper, Journ. de Gliim. Phys. 8 228 (l'Jlü;. 



