( 692 ) 



6. for . = 0.714 V,, = 74 



7/ = 65 X 10' 

 B = 61 X 10' 



7. for t ^ 0.68 V,, = 113 



,/ = 70 X 10' 

 e =57 XIO'. 

 The first of these belong to the triple-point gas-liquid-solid, 

 c.) The points of the liquid state belonging to 6 and 7 are ealcii- 

 lated with the help of Kuenen and Robson's nnmbers for the heat of 

 vaporisation. We have found 



8. for r = 0.714 r,, = 0,85 



7/ =— 102x10^ 

 8 = — 262x10' 



9. for t = 0.68 v„ = 0,83 



n = — 122 xio^ 

 8 = — 304x10' 

 In the same way taking into account the heat of fusion at the 

 triple point we find for a point belonging to the solid state. 

 10. for t = 0,714 vy = 0,68 



ij = — 187 X 10' 

 B = — 446 X 10' 

 The model (see PI. II fig. 2) is constructed with 



the values of?' in cms =^^U of the above numerical values 



_ 1 



,, ,, ,, 11] ,, )j — T Qa " " " " " 



,, J, ,, •- ?) 5j c\ 'ins " " " " " 



According to Tammann two solid modifications of COg exist so that 

 we must add two solid ridges (see PI. II fig. 2) in addition to the 

 liquid ridge. We have assumed that Tammann's 2"^ modification lies 

 between the fluid state and the first modification, and we call Tammann's 

 2"^^ modification A and his first B. The reason wh}^ we have assumed 

 this arrangement between the two solid modifications is the following : 

 Tammann ') has determined the fusion line for the modification .4 as 

 well as for B, and also the transition line for the second modification. 



He found (see PI. I fig. 1) that the values of y- are greatest for the points 



on the equilibrium line c, smallest for the fusion line a of the modi- 

 fication A and found between the two another locus for the fusion 

 line of the modification B. The same is also to be obtained from our 



1} Tammann, Ann. Phys. u. Chemie 1899 Bd. 68 pg. 553. 



