( 22 ) 



seems necessary to coiitiiiiially draw attention to this circumstance. 

 Already in 1893 in his thesis for a doctor's degree : "De afwijkingen 

 van de wetten voor verdnnde oplossingen" Hondius Boldingii used tiie 

 function — log {1 — .'.'); ^1*^<' ^'^^ correctioji term r-/;^ omitting however 

 the denominator (1 + ^'-O^- I^^'' Chatelier ^) used the simple equation (2) 

 in a somewhat moditied form for the melting-point-curves of alloys. 

 Tlie ^^ay however iji ^v]li(•ll he derived this equation is totalh' wrong '"). 



II. Many mclling-point-curves sliow the same type as those of 

 tin-amalgams; it may therefore be important lo investigate, ^vhether 

 they also may be represented by foi-mula (Ij. It nnisl liowever be 

 observed, that this foi-inula is appHcable only in the case that tlie 

 solid phase does nol form any mi. red rrijstals. If the fornnila (1) does 

 not hold good, this may therefore indicate tiie occurrence of mixed 

 crystals in the ^olid phase, though it is of coiii-se also ])0ssible that 

 other intluoices c. g. dissociating niiiltipic iiiolcculcs jiave caused the 

 deviation. 



In 1897 Heycock and Neville i. a. luade experiments on a great 

 many alloys"). They found that the alloy sUrer-lead shows the type 

 of tin-mercury very accurately (comp. the figure on p. 59 of their 

 paper). I have subjected the data relating to this point (coiuj». the 

 tables of p. 87 and 39) to some numerical investigations. 



The initial course is again nearly straight — up to about 20 atom 

 procents of lead — ■ and this i)art yields for tiie value 0,805. If 

 we now use this value for the calculation of the quantities a and /• 

 from the observations at lower temperature, we do not tind constant 

 values, as in the case of tin-mercury, l)nt considerably diiferent 

 values according as we have calculated these constants at mean tem- 

 peratures or at low temperatures. If we take the data for .t'=0,63 

 and ,7;=0,80, or ,i'=0,63 and a'=iO,96 (the eutectic point) as basis 

 for our calculation, then we find in both cases: 



« = 0,355 ; >• = — 0,325. 



The following table may show how bad the agreement is, specially 

 for the mean temperatures: 



1) See i.a, "Rapport etc." (Paris, Gauthiers-Villars) : La constitution des alliages 

 métalliques par S. W. Roberts-Austen et A. Staxsfield. (1900), p. 24. 



~) On different occasions I have pleaded already before for not omitting the 

 function log {\—x). (comp. i.a. Zeitschr. fur Phys. Ch. 15, p. 457 sequ. 1894). 



3) Complete Freezing-Point Curves of Binary Alloys, containing Silver or Copper 

 together with another metal (Phil. Trans, of the R. S. of Londen, Series A, Vol. 

 189 (1897), p. 25-69). 



