( 167 ) 



sition. Here the ('iis[) P lies at the same lieight as C; we find 

 therefore at the temperature of the eiiteotic point for the first time 

 four vahies of ,r' : ,i\' and .i'/ eorresi)onding to C, and tlie eoineiding 

 l)oints .(',/ and .// corresponding to /-*. These latter two points still 

 represent unstable conditions. A moment later /-* has risen above 

 f and the two coinciding points d\' and .i*/ have se[)arated (fig. 12). 

 The values ,i\' and .i\' always correspond to C, ,v./ and .r/ to two 

 other })()ints (►f the line 'f=/{.v). The phase to which ,/'/ relates, is 

 in)staJ>le, that to \vhich ,?;/ relates nietadahle. 



The transition of fig. 11 is determined in combination of (6) 

 for ,/■/ and .?•/ (with .6',.), for .v./ (with .v^), in comieclion with 

 the relation 7'= r/^ ji' .rj' (1— .i','). \^\ means of these relations we 

 may determine 2\ d\., d\ , x/ , .c,/ , .r/, /5', if we moreover take into accoujit 

 ,}\/ = Ï — .i\' (compare VI above). 



r. The figures lo and 14 represent a new and xcvy important 

 case of transition. Formerly the branch AR intersected the branch 

 HP always oji the left of the maximum (or mininmm) /) in the 

 eulectic point (': \n tig. 'J 3 it passes e.mct/// tlinHKjh the jioii/t I). 

 From this follows, that the point ,/'/ coincides in C with d\' (both 

 := .t), which point represents a stable phase from this moment. 

 Afterwards the minimum D lies on the left of the eutectic point 

 6' (see fig. 14) in consequence of which Üie realizable part of the 

 meltingpoint cur\'e begins to show a totally different shape, namely 

 icitlt a minimum (see fig. 14rr). The point ■/'./ which till now lay 

 on the left of C, lies in future on tlie rüjlit oï{\\i\X\Knn{. On the other 

 hand ,r/ has got on the left of C and it corresponds to a ])oint of 

 the line T ^ f {.i') between B and JJ. 



It will not escape our notice that the case drawn in fig. l-ia 

 occurs to some extent in the mixtures of Ag NO3 and Na NO,, inves- 

 tigated by Mr. Hissink (see fig. 14/>). The diiference is only that the 

 minimum D in the line T = f (.r) in the case of fig. 14/> appears 

 beyond .c =: 1 and has therefore already disappeared. In our case 

 we have supposed this to occur in a later stage. 



The case of transition of fig. 13 is calculated from the equations 

 (6) for .i\' and ,ej, taking into account .r==.r^', and moreover 

 .1;^' {= .t'^') =zl — ,L\'. The numerical solution of these equations yields 

 the following values : 

 i3' = 0,9247 ; .v/ = M94U ; .i-,' = .r/ _ .r, = 0,8060 ; 7' = 479°,1. 



We may then calculate -t'g' and ,L-g from etpiation (6). 



(/. Finally the figures 15 and 16 represent the most important 

 case of transition. 



