518 



pk 



/o^lO^:^= 5,585 5,424 4,891 4,475 4,384 4,256 4,238 4,059 3,932 3,686 2 006 

 P 



of =5,552 5,391 4,857 4,441 4,351 4,223 4,205 4,026 3,898 3,652 1,972 



Z^_l = 2,191 2,104 1,945 1,762 1,730 1,662 1,649 1,576 1.516 1,396 0,702 



of= 1,803 1,727 1,587 1,427 1,398 1,338 1,327 1,263 1,210 1,104 | 0,495 



hence ƒ10 = 2,55 2,58 2,51 2,54 2,53 2,56 2,57 2,58 2,59 2,64 | 2,86^-4,38 

 of=3,08 3,12 3,06 3,11 3,11 3,16 3,17 3,19 3,22 3,31 '3,98^-4,22 



It also appears clearly from these values of f, that the real critical 

 temperature will lie between 1605 and 1410. The limiting values 

 of / at Tk are fk = 8y = 10,09 to 9,71, hence /t^" = 4,38 to 4,22. 

 The value /j'" lies slightly too far from 4,38; the value 3,98 lies 

 too near it. 



7. Recapitulation of this group. In accordance with the 

 course of the vapour tension factors ƒ we shall assume the critical 

 temperature of sodium to be 2000° abs., i. e. V9 of the difference 

 between 1970° and 1730° higher than the first of these values. 

 Further that of Potassium to be 1710°, i. e. 7? of the difference 

 between 1770° and 1560° abs. loiver than 1770°; that of Rubidium 

 to be = 1590°, i.e. 7, of the difference between 1660° and 1450° 

 lower than 1660°; that of Caesium = 15107 i. e. V, of the difference 

 between 1605° and 1410° lower than the first value. At last that 

 of Lithium, in virtue of the value oi bk (which we assume = 145 . 10~^) 

 halfway between 2410° and 2700°, i. e. = 2550°, so that we get 

 the following survey. 



These are the most probable values following with pretty great 

 certainty from the available data. The inaccuracy will at most amount 

 to 1 or 2 7,. 



With regard to the values of bk we will only observe that they 



