261 



Mean, 27.2845, ± .0014 

 Hence B = 10.953. 



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

 now as follows : 



(1). Na„BA.10H,O:10H,O: : 100: 47.1654, ± .0052 

 (2). Na„BA-10H,O:2HCl: :100:19.0893, ± .0006 

 (3). Na^BAtSNaCl: : 100: 57.933, ± .0074 

 (4). 2AgCl:Na3A: : 100: 70.546, ± .0146 

 (5). S04:Na,BA: : 100: 210.052, ± .133 

 (6). 3AgCl:BCl3: : 100: 27.2845, ± .0014 

 (7). 3Ag:BBr3::100:77.425, ±.0017 

 (8). 3AgBr:BBr3:: 100: 44.512, ± .0009 

 (9). 3BaS04:B,S3: : 100: 16.8855, ± .0033 

 (10). CO, :B„C:: 100: 177.258, ±.024 



The values nsecl in redncing these ratios are — 



Ag = 107.880, ± .00029 

 CI = 35.4584, ± .0002 

 Br = 79.9197, ± .0003 

 Na = 23.0108, ± .00024 



Hence. 



From ratio 7 B = 10.8191, ± .0056 



" 5 10.9431, ± .0319 



" 1 10.9472, ± .0068 



" 6 10.9523, ± .0061 



" 3 10.9572, ± .0065 



" 2 10.9700, ± .0031 



"10 10.9994, ± .0018 



" 8 11.0211. ± .0051 



" 9 11.0236, ± .0122 



" 4 11.0544, ± .0105 



General mean, B = 10.9805, ± .0013 



In this combination, ratio 10 is enormously overvalued. It receives 

 weight out of all proportion to its merits. The uncertainties, however, 

 are so great that the final mean may be allowed to stand until better 

 evidence as to the true atomic weight of boron is obtained. The round 

 number 11.0 is enouffh for common use. 



