408 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



Still another method for determining the atomic weight of fluorine 

 was adopted by Julius Meyer/ Carefully purified calcium oxide was 

 weighed, slaked with water and then converted into chloride by means 

 of hydrochloric acid. The chloride solution was then repeatedly evap- 

 orated with pure hydrofluoric acid. The calcium fluoride so produced 

 was finally ignited to constant weight. On a vacuum basis his weights 

 were as follows. The third column gives the ratio CaO : CaFj : : 100: x: 



Weight CaO. Weight CaF„. Ratio. 



6.1883 8.6215 139.320 



4.2736 5.9548 139.339 



6.2931 8.7658 139.292 



5.7767 8.0485 139.327 



4.9836 6.9426 139.309 



Mean, 139.317, ± .0054 



Hence F= 19.035. 



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

 now — 



(1). CaO:CaF.: : 100: 139.317, ± .0054 

 ( 2 ) . CaF, : CaSO, : : 1.0 : 1.7444, di .00018 

 (3). 2NaF:Na.,S0,: : 1.0: 1.6867, ± .00038 

 (4). 2KF:K„S0,: : 1.0: 1.4991, ± .0007 

 (5). BaF2:BaS04: :1.0:1.3309, ± .00028 

 (6). PbF„:PbSO,: : 5.0: 6.1783, ± .0002 

 ( 7 ) . AnijMnFs : I :: 100 : 68.156, it .01 28 



To reduce these ratios we have — 



Ca = 40.1323, ± .0005 

 Ba = 137.363, ± .0025 

 Pb = 206.970, ± .0017 

 Mn = 54.947, ± .0005 

 K = 39.0999, ± .0002 



Hence, 



From ratio 2 ¥ = 18.973, ± .0041 



" 5 19.015, ± .0185 



" 4 19.024, It .0271 



" 1 19.035, ± .0016 



" 7 19.038, It .0070 



" 3 19.109, It .0085 



•' 6 19.136, It .0041 



Ueneral mean, F = 19.041, ± .00135 



' Zeitsch. anorg. CTieni., 36, 313. 1903. 



