( 190 ) 



fiiitliei- some Tj-r-sections coirespoiuliiig to different constant pressures 

 liave been indicated. 



When we consider tiie melting-point line for the pressnre of 45 

 atmospheres (in the figure the pressure has been gi\en for everj- 

 melting-point line), we observe that this melting-point line i-eally 

 possesses two vertical tangents, and that it runs strongly back 

 between the two points where the tangent is vertical. Below the 

 first, and above the second point the direction of the melting-point 

 line is normal, however, so at higher temperature it runs to the 

 side of the component with the highest melting point. 



It is easy to prove that this is in perfect harniojiy with the theory, 



for below and above the points where iihf is zero, iv^f must be 



negative (this follows from the intersection of the (P7',ƒ).rliues with 



fdx\ . 

 the plane tor constant pressure), so that T\ — I is positive. Between 



\dTjp 



the said points, on the other hand, w^f is positive, from which 

 tollows that T\ — is negative. 



If we now proceed to higher pressures, we see that at 50 and 

 52.8 atms. the melting-point line has still the same shape in the 

 main ; two points may, namely, be indicated where the tangent is 

 vertical, but in concentration these points lie further apart than for 

 lower pressure. 



At 54,3 atms. the melting-point line presents this peculiarity that 

 the upper point, where the tangent is vertical, lies exactl}' on the 

 vapour line of the three-phase region, from which accordingly follows 

 that there w^f = 0. 



The melting-point line under the pressure of 59 atms. shows that 

 the vapour line of the three-phase region is already met at a place 

 where u\,j is positive, so that the melting-point line now possesses only 

 one vertical tangent. 



At the pressure of 61 atms. the melting-point line no longer pos- 

 sesses a vertical tangent in the stable region, for where it meets the 

 \'apour branch of the three-phase region, ii\j is negative. So it appears 

 fiom this too, that the quantity Wsf on the vapour branch passes 

 from negative through zero, and becomes positive, after which it 

 soon passes through zero for the second time and assumes again a 

 negative value. As was already set forth in the communication on 

 the (/'*7l/)x-lines, this is to be ascribed to this that the locus for 

 iL\.f:=() gets outside the vapour branch on its approach of the plait, 

 but uot outside the liquid branch. 



