360 Or} the Proportion in tvhich Bismuth unites [Nov. 



assumed a snow-white colour, with the exception of a flock or two 

 of yellow.* The weight was now 48664, constituting an addition 

 amounting to 6782. This consisted of 



Oxygen in the oxide 1-128 



Sulphuric acid 5-654 



Now this portion of acid contains 3*3907 of oxygen. For 100 : 



59-97 :: 5-654 : 3-3907. And ^^ = M302, a number which 



surpasses the quantity of oxygen contained in the oxide only by 

 0002. That the salt was pure sulphate of bismuth was evident 

 from its snow-white colour, from the separation of sulphuric acid 

 during the exposure to a red heat, and from the homogeneity of the 

 mass both in colour and texture. The difference between the 

 temperature which is sufficient to drive off the excess of acid, and 

 which is requisite to decompose the salt, is so great that there is no 

 difficulty in making this experiment with accuracy. It is obviously 

 necessary to expose the neck of the glass to the same temperature 

 as the vessel itself, in order to prevent the sulphuric acid from con- 

 densing in it. 



The laws according to which bodies unite and separate from each 

 other are invariable. Yet it is impossible to expect that the results 

 of various experiments should perfectly agree with each other; even 

 vision itself is liable to be misinterpreted. The experiment which 

 seems to come nearest the truth is the saturation of the metal with 

 oxygen. Therefore I assume that 100 parts of metal combine with 

 11-28 of oxygen. From this it follows that 100 parts of metal 

 become 1677 L parts of sulphate of bismuth. This salt is composed 

 as follows : — 



uUth 5 ^" 



CBismut 



£ Oxygen 6-726 



66-353 



Add. ..A Sulphur 13-469 



£ Oxygen 20-178 



33-6-47 



100-000 



In this salt there exist 10 parts of metal and 2-259 parts of 

 sulphur. In the preceding experiments the greatest quantity of 

 sulphur combined with 10 bismuth was 2*252. This of course 

 comes nearest the truth. 



* Probably pure oxide. The want of oxygen in the first operation had o«a- 

 sioned the formation of some sulphite; but the additional nitric acid converted 

 these portions into sulphate. Perhaps a little oxide might be developed by the 

 red heat. • ■ • ° ■ } 



