of the Centenary of the Birth of Dr. Priestley. 39.5 



losophy. In the history of his life it is said, that coming to London, 

 as was his custom, a month every year, his acquaintance with Dr. 

 Watson, Dr. Price, Mr. Canton, and Dr. Franklin commenced about 

 1766 ; and then his first attempts at experimental philosophy began. 

 I think, however, there is evidence of his attachment to experimental 

 philosophy much earlier. I was looking this morning at a letter 

 which Dr. Priestley wrote to my grandfather respecting two of his 

 first pupils, my late revered uncle, and the father of my friend at my 

 left hand, Dr. Rigby, and I find that he particularly mentions in that 

 letter that out of school hours he directs the attention of his pupils 

 to natural philosophy as an amusement, and that they have the use 

 of his library and apparatus for this purpose, and were engaged in 

 experiments. I also find that when it was proposed he should be- 

 come a tutor at the Dissenting Academy at Warrington, the depart- 

 ment assigned to him was that of languages : he then represented that 

 he should have been more gratified to have undertaken that of natural 

 philosophy. He however went to Warrington, and became Professor 

 of languages ; he taught Hebrew, Greek, Latin, French, and Italian ; 

 he lectured, I believe with distinction, on civil law : some time after 

 that he contrived his Chart of Biography, and subsequently his Chart 

 of History, which, I believe, are the types of everything of that kind 

 which has since been produced. Dr. Priestley, besides all his other 

 studies, was an astronomer, though we do not generally know him 

 in that capacity. He was applied to to accompany Captain Cook as 

 astronomer in his second voyage round the world ; some objection 

 was raised, however, and it was given to Dr. Foster, who was also a 

 tutor at Warrington. On this occasion, Dr. Priestley, with his usual 

 candour, says, " It is given to a man far better qualified than myself, 

 as I know but little of natural history, though I think I could have 

 worked myself up to the point had it been necessary." 



With such men as Smeaton, and Watt, and Whitehurst, it was not 

 unlikely that Dr. Priestley's attention should be turned to that line 

 of science which he afterwards pursued with so much success. In 

 his visits to London he became more acquainted with scientific men, 

 and was excited to the pursuit of natural philosophy. His industry 

 was most extraordinary ; and, as an instance, I may mention that 

 he proposed to Dr. Franklin to write a history of electricity. Dr. 

 Franklin approved the plan, and offered to furnish the books neces- 

 sary for the purpose. In less than twelve months he sent Dr. Franklin 

 a printed copy of the work. He lectured during that year five hours 

 a day ; he made the experiments for that work, finished the drawings 

 for it, and he apologizes in one of his letters for its being one of his 

 most hasty productions. The work maintains, notwithstanding, a 

 very high regard among those who follow that science. 



Dr. Priestley had a particular aptitude in turning his knowledge 

 to useful purposes. In executing this very work, he perceived that 

 in the representation of apparatus all former delineations were un- 

 couth and unpleasant to look at. He examined into the cause, 

 found that the defect was in the perspective, and, setting to work, 

 studied Dr. Brook Taylor on the subject. Now, we know what 



3E2 



