502 



the two latter with almost pure molten material (99,7 to 100 7o)- 

 The value calculated b^' us seems to be sli^htlj too low. Possibly 

 b]c may be assumed too high. 



For the boiling point the exceedingly high temperature 2350° 

 (97 7o), i.e. 2623° abs., has been found b} v. Bolton (1910), and 

 also by Wkdfkinu and Lewis (1910), so that then T]c: T,,. would 

 amount to = 1,50. Also from this too low amount it would follow 

 that the critical temperature has been calculated too low in conse- 

 quence of the value of bk, which has been assumed too high. 



If for bk ■ ^0' instead of 237,5 we assume the value 210, which 

 also holds for Germanium, 7\ becomes about 4400°, and the ratio 

 Ti,: Tir I'ises from 1,5 to 1,7, the calculated limiting density becoming 

 slightly greater than 7, somewhat too great therefore. 



We calculate for pk '■ 



0,0312 X 1369. 10-4 



Pk = = 760 atm. 



^ 564,06.10-8 



10. Cerium. As 2-/ = 3.39, / = 0,851, we calculate: 



68,86 X 1521 



Tk = — ^iTTHTT = 3580° abs. 



29, 2o 



For 2y follows from this 2/ = 1 + 0,04 X 59,8 = 3.39, so that 

 we get : 



3,39 X 140,25 

 292^ 



6,92 (98 VJ was found by Hirsch (1912), and 7,04 by Muthmann 

 and Weisz (1904). The calculated value may possibly be somewhat 

 too high. 



As for the melting point 635° (98 7o) was found by Hirsch, and 

 623° C. by Muthm.ann and Weisz, we may assume the middle value 

 629° C. =902° abs. to be pretty accurate, so that Tk:2\r becomes 

 = 3,97. 



For pjc we find : 



0,0315 X 1521 . 10-4 

 ^' = 855,6.10-8 = ££0^tn^ 



^' = -1,5X22412 = ^-^ ■ (^'-'^'"'-tedj 



11. Thorium. As 2/ appears to be =3,17, and therefore P. is 



= 0,870, we get : 



70,40 X 1681 



Tk = -— = '^940° abs. 



> 4t',25 



This makes 2y really =1+0,04x54,2 = 3,17, and we find 



for Z>„: """ 



