FLUORINE. 279 



If we assign this equal weight with Berzelius' series, the data for this 

 ratio combine thus : 



Berzelius 1.7500, .0004 



Louyet, first series 1.7437, .0003 



Louyet, second series 1.7417, .0004 



De Luca with Dumas 1.7459, .0011 



Moissan 1.7427, .0004 



General mean 1.7444, .00018 



For the ratio between the two sodium salts we have experiments by 

 Dumas, Louyet, and Moissan. According to Louyet, one gramme of 

 NaF gives of Na 2 S0 4 



1.686 



1.683 



1.685 



Mean, 1.6847, .0006 



The weighings published by Dumas are as follows : 



.777 grm. NaF give 1.312 grm. Na 2 SO 4 . Ratio, 1.689 



1.737 " 2.930 " " 1.687 



Mean, 1.688, .0007 



Moissan says only that five experiments with sodium fluoride gave 

 . F = 19.04 to 19.08. This was calculated with Na = 23.05 and S'= 32.074. 

 Hence, reckoning backward, the two values give for the standard ratio 



1.6873 



Mean, 1.6881 



Giving this equal weight with Dumas' mean, we have 



Louyet 1 .6847, =fc .0006 



Dumas 1.688, .0007 



Moissan 1.6881, .0007 



General mean 1 .6867, .00038 



Dumas also gives experiments upon potassium fluoride. The quantity 

 of sulphate formed from one gramme of fluoride is given in the last 

 column : 



1.483 grm. KF give 2.225 g rm - K 2 SO 4 . 1.5002 



1.309 " 1.961 " 1.4981 



Mean, 1.499^ .0007 



The ratio between barium fluoride and barium sulphate was measured 



