I JOSEPH PRIESTLEY 21 



stances, a nearer affinity with the spirit of nitre 

 than that kind of eartli with which it is united in 

 the atmosphere." * 



It would have been hard for the most ingenious 

 person to have wandered farther from the truth 

 than Priestley does in this hypothesis; and, though 

 Lavoisier undoubtedly treated Priestley very ill, 

 and pretended to have discovered dephlogisticated 

 air, or oxygen, as he called it, independently, we 

 can almost forgive him when we reflect how 

 different were the ideas which the great French 

 chemist attached to the body which Priestley dis- 

 covered. 



They are like two navigators of whom the first 

 sees a new country, but takes clouds for moun- 

 tains and mirage for lowlands; while the second 

 determines its length and breadth, and lays down 

 on a chart its exact place, so that, thenceforth, it 

 serves as a guide to his successors, and becomes 

 a secure outpost whence new explorations may be 

 pushed. 



^NTevertheless, as Priestley himself somewhere 

 remarks, the first object of physical science is to 

 ascertain facts, and the service which he rendered 

 to chemistry by the definite establishment of a 

 large number of new and fundamentally important 

 facts, is such as to entitle him to a very high place 

 among the fathers of chemical science. 



* Ihid. p. 60. The italics are Priestley's own. 



