[ 376 ) 



The extraordinarily ^"reat curvature of tlio central part of the line 

 Avonld lead to the siij)i)osition that the li(|uid mixtures of Su -j- Hj2; 

 in the absence of a solid pliase would on further coolin<i' separate 

 into two layers. 



()n coolin*»- below — 34.5° a chan;[>e takes place in all auialiiianis 

 from 0.3 to 85 "/lu accom[)ani('d by a (kn'ided evolution of heat and 

 decrease of volume. Willi increasing- concentrations of Su it lirst 

 increases but then decreases in intensity. The maxinnim lies near 

 50 7,r This change occurs in the iignre on the line ('D which 

 therefore inns to at least 85 "/o- 



The change causes a new piuise to appear which also belongs to 

 the second solidifying-line ('A. The mnximum in the intensity of 

 tiie change on CD at about 50"/„ would lead us to sui)pose that 

 mixed crystals having about this composition are formed. Tlie ukxH- 

 lication of tin tiierein contained must differ from ordinary tin. 



Between — 34°. 5 and — 38°. 5 these mixed crystals conlinne to be 

 de[>osited from the motlier-li([iior (which moves along tlie line (\\), 

 this is accompanied by exj)ansion. This change in volume (niuinislies 

 as the amount of tin |»reseiit increases and (bes out near 75 "/„. 

 The solidilication point of pure mercury and also the final solidiil- 

 catioii point of all amalgams containing up to about 60 "/„ Sn, lies 

 at — 38°.6 (line AE). As the line (A of the saturated solutions 

 also ends here it would seem that at tiie solidifying point of Hg, 

 the solubility of tin has decreased to 0, so that instead ofaeutectic 

 mixture only the remaining mercury solidities. 



Still, the point A bears cpiite the characteristic of a eiileclic point 

 as not only the line .lA' is hori/ontal, but all mixtures up to tiO "/„ 

 Sn also remain a shorter or longer time at this temperature ^vhi(•ll 

 proves that a residual licpiid is solidifying completely. 



A great uncertainty still exists as to the nature of the liu-iuodili- 

 calioii which occurs in mixed crystals below — 34°. 5 cliictly because 

 it has so far not been |)ossible to discover the part played in the 

 amalgams by the grey modilication of tin which may occur below 

 20° V. 



lint from the change in volume which lakes place in the ditlerent 

 transformations at and below — 34°. 5 we may argue that thespecitic 

 volume of the tin must be smaller than that of the grey moditicatioJi 

 and larger than that of li([uid and, therefore, also of ordinary tin. 



