BISMUTH. 407 



for he found the constituents by analysis to be* 



Tin . 100 or 7'25 



Sulphur . 56-25 - 4-078 



SECT. IV. 



OF THE ATOMIC WEIGHT OF BISMUTH. 



IN order to determine the atomic weight of bis- 

 muth with accuracy, it is requisite to employ 

 that metal in a state of purity. The bismuth of 

 commerce is usually contaminated with iron, and 

 almost always contains some sulphur. To obtain 

 pure bismuth, I dissolved a quantity of the bis- 

 muth of commerce in nitric acid. The crystals 

 of nitrate of bismuth being thrown into water, 

 were decomposed, and a white powder, consist- 

 ing chiefly of hydrated oxide of bismuth, fell to 

 the bottom. This hydrate was well washed, 

 dried upon the filter, and reduced to the me- 

 tallic state, by heating it in a covered crucible 

 with black flux. 



1. Nine grains of bismuth purified in this way, Atom of 

 were put into a platinum crucible, and dissolved bismuth, 

 in nitric acid. The solution was evaporated to 

 dryness by a gentle heat, which was afterwards 

 gradually raised till the crucible became percep- 



* Phil. Trans. 1812, p. 199. 



