112 JOSEPH PRIESTLEY. [LECT. 



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 deter- 

 mines 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 out- 

 post whence new explorations may be pushed. 



Nevertheless, 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. 



It is difficult to say whether Priestley's philo- 

 sophical, political, or theological views were -most 

 responsible for the bitter hatred which was borne to 



1 " Experiments and Observations on Different Kinds of Air," vol. 

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



