515 



2y = 2,548 to 2,447, y=l,27 to 1,22. We find therefore 0,560 to 

 0,550 for y : (1 -}- y), hence according to our formula A = 0,922 to 

 0,930, and (f = 74,60 to 75,25. Hence 



2,548 X 85,45 217,7 ^^^ ,^ . 

 1,648X22412 36930 ' 



2,446 X 85 ,45 ^ 209,0 



or Oj!. = = =557.10 ^\ 



1,673 X 22412 37500 



Z)o being =1,648 to 1,673. For, according to Hackspill Z) = 1,475 

 diquid) for 38°, 5, hence according to the formula derived by us: 



/ oil c^ 



1,475 = D, M -0,560 -^ | = 0,895 Z>J 



or = X>„ f 1-0,550 ^^ ) = 0,882 D, 



We find further for au: 



1660X59,0.10- 97940 ,,_,^,^,,,,. 



1^-lZ. . 10-4 — 1073 10-4 



We find for p^: 



1660 1660 



Pt == =: = 129 atm. 



^^ 2185 X 590.10-5 12,89 



_ 1450 1450 _ 



^^ ^^ ~ 2185 X 557.lF^"T2J7 "^ ^^^ " 



which causes log'' pt = 2,110 to 2,076. 



From the above values of y we find for the coefficient of expansion 

 a, resp. with 7^ = 1660 and 1450 abs. : 



0,560 0,560 



1660 — 0,560x363 1457 



384.10-« 



0,550 0,550 



or a = = - =440.10-6 



1450 — 0,550 X 363 1250 



while Hackspill gives 339 . 10— ^ between 40° and 140° C. (mean 

 temperature 90° C. = 363 abs.). Here too the first value 38 . lO-^ 

 is nearer the experimental value 34 (which will have to be raised 

 somewhat, see for potassium and sodium) than the second 44. 10-^. 

 Hackspill gives for the vapour tensions of Rubidium : 



