AZOTIC GAS. 108 



the solution of muriate of barytes, and into the 

 other, a little of the solution of sulphate of soda. 

 But no precipitation, or even opalescence, was 

 produced by either of these re-agents ; showing 

 that the liquid contained no sensible quantity of 

 sulphuric acid, or of oxide of lead. 



From this experiment it follows, that the 

 sulphuric acid in nine grains of anhydrous 

 sulphate of soda, is just sufficient to saturate the 

 oxide of lead in 20*75 grains of nitrate of lead ; 

 but nine grains of anhydrous sulphate of soda 

 contain five grains of sulphuric acid, which re- 

 quires just fourteen grains of protoxide of lead to 

 saturate it. Accordingly, if the sulphate of lead 

 precipitated be washed, collected, and dried, 

 without any loss, it will be found to weigh 

 exactly nineteen grains. Thus, it is proved, that 

 20*7<5 grains of nitrate of lead contain 14 grains 

 of protoxide of lead. So that nitrate of lead is 

 composed of 



Protoxide of lead 14 

 Nitric acid 6-75 



20-75 



The salt being neutral, and 14 denoting an 

 integral particle of protoxide of lead, it is clear 

 that the atomic weight of nitric acid is 6*75. 



3. The importance of an accurate knowledge A d nitrate 



. , . . , of silver. 



ot the atomic weight of nitric acid is so great, 



G 4 



