SULPHUR. 209 



gas and the specific gravity of phosphorus vapour 

 added together, or 0-9722. For, 



Twice sp. gr. of hydrogen gas = 0-1388 

 Sp. gr. of phosphorus vapour = O8333 



0-9722 = sp. gr. of the 

 gas. 



Bihydroguret of phosphorus is the fourth gas 

 which we have met with, possessed of this speci- 

 fic gravity. The other three are azotic gas, car- 

 bonic oxide, and olefiant gas. 



Thus it appears, that the composition and ato- 

 mic weights of the various compounds of phos- 

 phorus with oxygen and hydrogen are as fol- 

 lows : 



PHOSPHORUS. OXYGEX. ATOMIC WEIGHT. 



1. Phosphorous acid . 1 atom + 1 atom 2-5 



2. Phosphoric acid .1 +2 3-5 



HYDROGEN. 



3. Phosphuretted hydr. 1 + 1 atom 1-625 



4. Bihydroguret of phosph. 1 +2 1*75 



5. Subphosphuretted hydr. 0-75 + 1 1-25 



Bihydroguret of phosphorus has both the specific 

 gravity and atomic weight of azotic gas. 



SECT. V. 



OF THE ATOMIC WEIGHT OF SULPHUR. 



SULPHUR forms three acid compounds with 

 oxygen, distinguished by the names of hyposul- 



VOL. I. O 



