FLUORINE. 243 



Louyet, 1849, Fluorite, 6 Det. Mean 1.7437, i high. 

 Artif. 3 Det. " i-74i7> 19 low. 



De Luca, 1860, Fluorite, 4 Det. " 1-7459; 23 high. 



Dumas, 1860, Fluorite, i Det. " 1-7455? 19 high. 



Moissan, 1890, 2 Det. No data given. 



Naz O4 S : 2 Na Fl = 142 : 84= 1.69 048. Chg. 402 low. 



Record to 4 places only : 1.69 05. cf 40 low. 



Louyet, 1849, 3 Det - Mean 1.6847, 58 low. 



Dumas, 1860, 2 Det. " 1.688, 25 low. 



Moissan, 1890, 5 Det. No data given. 



Ka2 O4 S : 2 Ka Fl=i74 : 116=1.50 ooo. Chg. 258 low. 



Record to 4 places only : 1.5000. " 26 low. 



Dumas, 1860, 2 Det. Mean 1.4991, 9 low. 



Ba O4 S : Ba Fl3=233 : 175 = 1.33 143. Chg. 152 low. 



Record to 4 places only : 1.33 14. Chg. 15 low. 



Louyet, 1849, 3 Det. Mean 1.331, 4 low. 



Moissan, 1891, 2 Det. No data given. 



It is to be regretted that the determinations of Moissan 

 cannot be used, he having failed to give any direct weigh- 

 ings. See p. 35. 



The principal data are those of Louyet, who lost his life 

 on account of this work. It is sufficient to establish Fl = 19. 

 On account of the low value, four decimals are perfectly 

 sufficient. 



By the value given for the change, the analytical excess 

 stated, give for Louyet's determinations, from Fluorspar 

 18.999, f rom the sodium salt, 19.15 and from the barium 

 compound, 19.025. As the pure fluorite is probably the 

 purest, the standard 19 is the true, absolute value within the 



H = 1 HYDROGEN. 



This atomic weight is commonly taken as unit. But it 

 cannot be taken as standard, for hydrogen cannot be weighed 

 with precision, being a gas. 



We have said sufficient on the questions here involved, 

 especially in our True Atomic Weights. It will incidentally 

 be shown here also. 



