ATOMIC WEIGHTS 



259 



Mean, 19.0893, ± .0006 

 Hence B = 10.970. 



Obviously, this error should be increased by tlie probable errors in- 

 volved in standardizing the acid, but they are too small to be worth 

 considering. 



The work of Armitage on the atomic weight of boron was published 

 only in abstract.^ The data, however, were fortunately given to Brauner,* 

 who has stated them in partially available form. First, six determinations 

 were made of the proportion of water in borax giving in mean, 47.1475 

 per cent., with a minimum of 47.1324 and a maximum of 47.1637. 

 Hence B = 10.983. If these figures alone are considered, the probable 

 error of the mean is ±.0091. Secondly, anhydrous borax was titrated 

 with standard sulphuric acid, with the subjoined results: 

 Na^B^Oj. 80^. Ratio. 



1.94033 .924615 209.053 



1.50303 .743413 210.251 



Mean, 210.052, ± .133 



Hence B = 10.943. The determination is evidently of small significance. 

 Combining the data relative to the percentage of water in borax, we 

 have — 



Berzelius with Laurent 47.130, ± .0130 



Dobrovolsk3^ 1 47.211, ± .0230 



Dobrovolsky, 2 46.878, ± .0720 



Hoskyns-Abrahall 47.2866, d= .0171 



Ramsay and Aston 47.1677, ± .0086 



Armitage 47.1475, ± .0091 



General mean 47.1654, ± .0052 



This mean is very close to that of Eamsay and Aston. Dobrovolpk3''s 

 figures count for practically nothing. 



^ Proc. Chem. Soc, 14, 22. 1898. The communication was followed by several adverse criticisms. 

 See also Leonard, Chem. News, 77, 104. 

 *0p. cit. 



