( 523 ) 



When the vahic of .i' is small, and assuming, that iiieiriirv dissolved 

 in thi is inonatonHC, \\q find for </„ by cahMdalion 2550 grani-cals. 

 Person found experimenhiUy 1690 gram-eals. Shoidd tliis ligin'e I»e 

 confirmed, it would prove, that the assoeiationfaclor of mercury is 

 about 1.5. 



Now, it follows from the above formula, tlial al 25°, where .c is 

 about 1, (/ ought to be 



= 2550 X 1,<3114 = 4110 graui-cals., 



whilst VAN Hetkken, by electromotive measurements, foujul abotil 

 3000 gram-cals. From this it would follow, that the value, used for 

 q^, is about 1.4 times too large, which would be a confirmation of 

 the fact, that the mercury in the amalgam is not present as sijigle atoms. 

 In order to obtain certainty as regards the molecular coJidilion of 

 the tin in the amalgam, it would be necessary to know the meltino- 

 point-line of the mercury, and to determine the lowering of the 

 melting-point in addition to the heat of fusion in the presence of 

 very small quantities of tin. There are indeed indications, that the tin 

 is also not present as single atoms. Indeed, the quanlily ;• = — 1)^ -j- />_, 



which was found bv us to be — 0,74, gives for - the value 26 



from ^vliich it would follow, that the nu)lecular volume of \\n {!> ) 

 would be about four times larger than that of mercury (/>,). Now, 

 the atomic volume of Hg is 'J 4,7, that of S]i = 16,l, so if these t^vo 



components were monatomic, — ought to be approximatelv = J 



h, ^ ' ' 



whilst in reality that relation is ^/^; tins points to the probability, 

 that in the case of tin several (may be six) atoms are united to 

 one molecule. 



It certainly would be highly desirable if (his question were fully 

 investigated. For in all our calculations (he \alues of ./; are only 

 then valid, when both mercury and tin ai e assumed to be monatomic. 

 This is also the case with all similar calculations, relating to other 

 amalgams. 



May I be allowed to point out, that the molecular condition of 

 merciiry may be determined from the lo\vering of (he melting-point 

 of tin, if this contahis a little dissolved mercury — whilst the molecular 

 condition of tin may be ascertained from the lowering of the melting- 

 point of mercury in (he ])resence of a little tin. For in (he case of 

 dilute solutions something is learned only about (he condition of (he 

 dissolved substance, but never anything as regards that of the solvent. 

 In the limiting formula 



