1 8 Literary and Philosophical Society. 



of the roads being far from excellent in those days, as well 

 as on account of the mode of swinging the vehicles. He 

 soon began to think in a manner different from his fellows, 

 and to attempt to clear up to his own mind the duties of 

 all members of Society, towards themselves and especially 

 the poor. His experimental essays on scientific subjects 

 cannot be considered important. Most of them were useful 

 only as being suggestive for the time, and the results have 

 much of that indefiniteness that is found in the transition 

 age of chemistry and medicine, with both of which studies 

 he was industriously engaged. This indefiniteness is more 

 provoking than even alchemy itself, in which one is scarcely 

 disappointed when the process spoken of is beyond com- 

 prehension. It arises from imperfect experiments — the key 

 to explanation had not come. But Priestley was working 

 at the same time and in a very different way, showing 

 that the mastery was not gained by opportunity in which 

 Percival had the advantage. 



The earlier essays were published by different societies 

 and in various ways, although afterwards collected. A 

 second series of essays was published in 1773, entitled 

 * Essays Medical, Philosophical, and Experimental,' which 

 made his reputation wide. 



It is not intended to claim for him that all the ideas 

 found in these essays were new, and it may be that none 

 of them had the highest order of originality ; but it is clear 

 that he came to Manchester with remarkably wide thoughts 

 on medicine and on science generally, and on the state of 

 the country and of humanity. It is true that Dr. White 

 was earlier in Manchester than Dr. Percival, and his son, 

 Mr. Charles White, the surgeon, a contemporary ; but Mr. 

 White's mind was original in a different direction, and 



