FLUORINE. 



281 



The ratios from which to compute the atomic weight of fluorine are 

 now — 



(i.) CaF2 : CaSO^ : : i.o : 1.7444, ± .00018 

 (2.) 2NaF : Na^SO^ : : i.o : 1.6867, ± .00038 

 (3.) 2KF : KjSO^ : : 1.0 : 1.4991, ± .0007 

 (4.) BaF.^ : BaSO^ : : 1.0 : 1.3309, ± .00028 

 (5.) PbF.^ : PbSO^ : : 5.0 : 6.1783, ± .OO02 

 (6.) Am/MnF^ : I : : 100 : 68.156, ± .0128 



To reduce them we have — 



And the values derived for fluorine are as follows: 



From (i) F^ 18.844 



From (2) , 

 From (3) . 

 From (4) . 

 From (5). 

 From (6). 



= 18.948 



= 18.877 

 = 18.869 



= 18.997 

 = 18.853 



General mean F = 18.912 



.0048 

 .0108 

 .0276 

 .0192 

 .0047 

 .0073 



zb .0029 



If = 16, F = 19.056. 



In all probability these values for fluorine average a trifle too high. 

 It is difficult to be certain that a fluoride has been completely converted 

 into sulphate, and an incomplete conversion tends to raise the apparent 

 atomic weight of fluorine. This possible source of error exists in all of 

 the ratios except the last one, but the fair concordance of the results 

 obtained seems to indicate that the uncertainty cannot be very large. 



