104 Chemical Philosophi/. [Chap. II. 



dish, pneumatic chemistry was enriched by the adr 

 dition o{ Azotic gas to the list of substances before 

 known. — This gas was discovered in 1772 by Dr, 

 Rutherford, noAV professor of botany in the univer- 

 sity of Edinburgh, and an account of it published 

 in his thesis De Acre Mephiti.co^ in the same year, 

 M. Lavoisier, in 1115, made known this gas as ^ 

 component part of atmospheric air. About the 

 same time it was procured by Scheele, and proved 

 to be a distinct fluid. Its specific gravity has been 

 investigated and determined by Kirwan and La- 

 voisier, the latter of whom makes it 0.00 11 o, or to 

 common air as 942.6 to 1000. The combustibility 

 of azotic gas, and the production of nitric acid by 

 this process, were first discovered by Mr. Caven- 

 dish, and communicated to the Royal Society in 

 1785. The name Azote was given to this gas by 

 the French academicians, and is derived from its 

 incapacity to support life. 



The discovery of Oxygen was another very im- 

 portant step in the course of chemical improve- 

 ment. The gas, the base of which is commonly 

 known by this denomination, was discovered by 

 Dr. Priestley, on the 1st of August, 17/4, and 

 called by him dephlogisticated air. Mr. Scheele, 

 of Sweden, as was before observed, discovered it in 

 1775, without any previous knowledge of what 

 Dr. Priestley had done ^ and gave it the name of 

 empyreal air. Condorcet gave it first the name of 

 vital airy and M. Lavoisier afterwards gave it the 

 name of oxygen gas, which is now generally 

 adopted. 



The discovery of this substance, and the inves- 

 tigation of its properties, deserve to be ranked 



