120 JOSEPH PRIESTLEY. 



ing, in such circumstances, a nearer affinity with the 

 spirit of nitre than that kind of earth 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 discovered. 



They are like two navigators of whom the first 

 sees a new country, but takes clouds for mountains 

 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. 



Nevertheless, as Priestley himself somewhere re- 

 marks, the first object of physical science is to ascer- 

 tain facts, and the service which he rendered to chem- 

 istry 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. 



It is difficult to say whether Priestley's philosophical, 



* " Experiments and Observations on Different Kinds of Air," TO!, ii. 

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



