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PEIESTLEY. 



MENTION has already been more than once made of 

 Dr. Priestley ; and certainly history would imperfectly 

 perform its office of recording the progress of natural 

 knowledge should it pass over his important discoveries 

 without the large share of attention and of praise which 

 they are well entitled to claim. In turning, however, 

 to recount the events of his life, we make a somewhat 

 painful transition from contemplating the philosophic 

 character in its perfection, to follow the course of one 

 who united in his own person the part of the experi- 

 mental inquirer after physical truth with that of the 

 angry polemic and the fiery politician, leading some- 

 times the life of a sage, though never perhaps free from 

 rooted and perverted prejudice sometimes that of a 

 zealot against received creeds and established institu- 

 tions, and hi consequence of his intemperance, alter- 

 nately the exciter and the victim of persecution. 

 Nevertheless, the services which he rendered in the 

 former and better capacity, ought to be held in grate- 

 ful remembrance by the cultivators of physical science. 

 Nor are we to suppose that even in his polemical 

 capacity he was not in pursuit of truth. He may have 

 had a tendency to oppose established opinions; a 

 disposition which led him, as he says himself, at the 

 age of twenty " to embrace what is generally called the 

 heterodox side of every question,"* just as he had a 

 disposition pertinaciously to keep by the received and 

 erroneous chemical theory ; but if he thought for him- 



* Works. Memoirs, vol. i., part i., p. 25. 



