FLUORINE. 



79 



Starting with fluor spar, Louyet found of sulphate as 

 follows : 



.0003 



A second series, upon artificial fluoride, gave : 



1-743 

 1. 741 

 1. 741 



Mean, 1.7417, dr .0004 



Dumas* published but one result for calcium fluoride. 

 .495 grm. gave .864 grm. sulphate, the ratio being 1 : 1.7455. 



De Lucaf worked with a very pure fluor spar, and pub- 

 lished the following results. The ratio between CaS04 and 

 one gramme of CaF2 is given in the third column : 



.9305 grm. CaF2 gave 1.630 grm. CaSO^. 



.836 " 1.459 



.502 " .S755 



-3985 " -6945 



1. 7518 

 1-7452 

 1.7440 

 1.7428 



If we include Dumas' single result with these, we get a 

 mean of 1.7459, ± .0011. 



Upon combining all these series, we get as follows : 



Berzelius i 



Louyet, 1st series i 



" 2d " I 



De Luca and Dumas i 



General mean i 



7500, ± .0004 



7437, ± .0003 



7417, zt .0004 



7459, =b .0011 



74493, 



.0002 



For the ratio between the two sodium salts we have ex- 

 periments by Dumas and by Louyet.J According to Louyet 

 one gramme of NaF gives of Na2S04 : 



* Ann. Chem. Phann., 113, 28. i860. 

 f Compt. Rend., 51, 299. i860. 

 I See the papers already quoted. 



