( 571 ) 



It is further te he seen in tliis ^,,r-section, that the Uvo nietastable 

 throe j)hase |ircssiire lines for 5.4+ G -\- L and for Sb-{- L -\- G 

 lie alxive the stable three phase pressure line for Sa-\- Su-\- G, 

 and tiiat tiie first lies between the two others. At the same time we 

 see that the chariicter of tlie solubility isotherms does not eliange, 

 the only modilii-alion which is brought about for each of the isotherms 

 conijjared with llio usual case is this that the metastable part is 

 enlarged. 



If we now take a temperature which lies still somewhat lower, 

 viz. t^, we get a /<,.i'-section as represented in fig. 5. All the three 

 phase ])ressnre lines have tlivergod, and descended, except that for 

 N.i + >'/;+ />. which has strongly ascended. The second point of 

 intersection lies now, in agreement with what the dotted line for the 

 temperature /, traced in the /^, 7-prqjec(ion shows, far above the 

 point indicating the \a[K)ur tension of the supercooled liqnid of A. 

 The metastaiile part of the two solubility isotherms has greatly in- 

 creased, and with it the region for ,S'j -|- .S'/,> . With further decrease 

 of temperature the character of the modifications in the />,,('-section 

 remains the same, so that it is unnecessary to e.xamine another. 



If we had applied the same considerations to the case that the 

 eutectic melting-point curve has a po.sitive course, we should, with the 

 exception of the unstable region, have found but one (lower) point 

 of intersection for the solubility isotherms, for the branches which 

 gave a second (higher) point of intersection in the case under dis- 

 cussion, recede continually from each other. 



I have not represented this latter case, as it yields nothing special. 



The case treated shows once more, how the e.xamination of the 

 equilibria which are hidden from our eyes, may conli'ibute to widen 

 our insight into those accessible to experiment. 



Amderdain, December 11)05. 



Aiioiydnic ('hi'iiilail hibunitorn of the Cniver^itii. 



Chemistry. — "On the phenonwna vJiirli occur ii-lien tlw plait [toiiit- 

 ciirve meets the three phiise line of a dissoclatintj l/hiari/ 

 compound". By Dr. A. S.mits. (Communicated by Prof. H. W. 



l')AKHt IS KoO-SEBOOM). 



1. In a previous paper ') I have already pointed out, that the 

 interestinji; systems metal-oxygen, metal-hydiogen and metal-nitrogen, 

 to which we may still add many of the systems metal-halogen, and 

 metaliixyde-acidanhyilride, iiclonii to the type etlier-autlii'aipiinone, 



) Zeilschr, f. pbysik. tbeia. 51, 193 (1905.) 



