517 



/ 301, 3\ 



1,845 = D, n -0,558 — ^ j = 0,895 D, 



, 301, 3\ 

 or = />„ f 1 - 0,548 I = 0,883 I) 



1410 y 



And we find for dj- : 



1605X72,5.10 -4 _ 116360 



1410X68,8.10-4 97010 



dk 



10-4 _-, ]55(j . 10 4 



or ak 



75,36 75,36 



giving \/ajc =39,4 a 35,9. 10 '^ 

 And for pk we find : 



1605 



= 10-4=1287.10-4 



PIc = 



or Pk = 



2185X725. 10--'^ 



1410 



2185X688TT(F5 



giving %'>A: = 2,01 to '1,97. 



Tiie coefficient of expansion may be calculated from 



0,558 0,558 ^^^ ^ ^ ,. 



1605—0,558X337 1417 



= 394 . 10 



0,548 0,548 



or « = — ■ — = = 447 .10 " 



1410-0.548x337 1225 



The value 39 . 10 •'^ was found between 17° and 100° C. (mean 

 63^5 C = 337° abs.) by Eckhard and Grakfk (1900). As these 

 experimental values had to be raised a little nearly everywhere in 

 order to get into agreement with the normal expansibility at higher 

 temperatures, given by y (the older values of Hagen for Caesium 

 lie still lower, viz. mean 345.10-"), it is possible that the critical 

 temperature of Caesium will lie between 1605° and 1410° abs. 



Let us consult the vapour tensions. Hackspill found : 



= 230 244 272 308 315 330 333 350 365 397 670° C. 



r=503 517 545 581 588 603 606 623 638 670 943° abs. 



p = 0,2 0,29 0,99 2,58 3,18 4,27 4,45 6,72 9,01 15,88 760 mm. 



logiop =0,301(-1) 0,462(~1) 0,996(-l) 0,412 0,502 0,630 0,648 0,827 0.955 1,201 2,881 



We find 4,886 to 4,853 for %*>^, and further: 



