24 HISTORICAL INTRODUCTION. 



by Dr. Prout, " On the Relation between the Spe- 

 cific Gravities of Bodies in their Gaseous State 

 and the Weights of their Atoms. 55 This paper 

 displays a degree of sagacity that has seldom 

 been exceeded in chemical investigations, arid 

 shows clearly liiat the author, if he chose, might 

 rise to the highest eminence as a chemical phi- 

 losopher. He proves, in the first place, that if air 

 be a compound of 20 volumes of oxygen and 

 80 of azotic gas, then the specific gravities of 

 these gases are 



Oxygen I'llll 

 Azotic 0-9722 



He shows also, that the specific gravity of hydro- 

 gen gas is 0*0694 : that if we reckon the atomic 

 weight of hydrogen 0*125, that of oxygen is 

 unity. The following table exhibits the num- 

 bers which he determined for several simple 

 bodies and most of his determinations were the 

 result of direct and very accurate experiments : 



1 Oxygen . 1 



2 Azote . 1-75 



3 Hydrogen . 0-125 



4 Chlorine . 4-5 



5 Iodine . 15-5 



6 Carbon . 0-75 



7 Sulphur . 2 



8 Phosphorus . 1*75 



9 Calcium . 2-5 

 10 Sodium 3 



