BORON. 19 



K.Schneider: 208 (0 = 16); 1299.98 (0 = 100). 



Determined by eight experiments on the conversion of 

 metallic bismuth into oxide by solution in nitric acid and 

 decomposition of the nitrate in the same vessel. The es- 

 caping gases were led through nitric acid, and the bismuth 

 caught in this way was separately converted into oxide and 

 weighed. In four experiments the bismuth was prepared 

 by the reduction of basic nitrate, and for the other four by 

 the reduction in hydrogen of the oxide formed in those 

 which preceded. 100 bismuth oxide were found to contain 

 a mean of 89.655 metal ; extreme dift"erence, 0.048. {T^og- 

 gend. AnnaL, 82, 1851, 303.) 



J. Dumas: 210.44 (0 = 16). 



Determined by seven experiments on bismuth chloride, 

 which was decomposed in solution by sodium carbonate, 

 and the sodium chloride thus formed titrated with silver 

 solution. The value taken is the mean result. The extreme 

 difference is 1.12. Dumas takes Ag = 108, and CI ^ 35.5. 

 The bismuth chloride was prepared by the action of chlo- 

 rine on bismuth, and was purified by fractional distillation 

 over bismuth. That employed in the experiments was 

 colorless. {Annal. de Chimie et de Physique, (3,) 55, 1859, 

 176.) 



BORON, 



The specific gravities of a number of volatile compounds 

 of boron have been determined by Dumas, Woehler and 

 Deville, and others, and correspond to an atomic weight of 

 about 11. [Gmelin-Kraut, l. c; L. 3Ieyer, I. c.) 



H. F. Weber has discovered that the specific heat of boron 

 rises rapidl}"- with the temperature, becoming nearly constant 

 at 600°. Above this temperature its specific heat is 0.5, and . 

 its atomic heat 5.5. {Foggend. Annul., loJf., 1875, 575.) 



J. J. Berzelius : 11.01 (0 = 16). 



Davy's investigations having shown that boracic acid con- 

 tains about 68 per cent, oxygen, and having thus established 

 the formula of borax, Berzelius determined the atomic 

 weight from the water contents of that salt. He found in 

 three experiments, without variation, 47.1 per cent. Gme- 

 lin-Kraut recalculates this composition with Stas' atomic 



