EARLY LIFE. 71 



papers long since given in the Philosophical Trans- 

 actions, and in the Memoirs of the National Institute 

 of France, the existence of this property is fully 

 shown by various experiments. 



Besides the two optical papers (1796-1797), there 

 was one on Porisms, inserted in the Philosophical 

 Transactions the year after (1798). 



Great as was the pleasure and solid advantage of 

 studying under such men as Playfair and Stewart, 

 the gratification of attending one of Black's last 

 courses exceeded all I have ever enjoyed. In my life 

 of that great man ('Lives of the Philosophers') 

 I have attempted to describe this pleasure.* Not a 

 little of this extreme interest certainly belonged to 

 the accident that he had so long survived the period 

 of his success that we knew there sat in our pre- 

 sence the man now in old age reposing under the 

 laurels won in his early youth. But, take it altogether, 

 the effect was such as cannot well be conceived. I 

 have heard the greatest understandings of the age 

 giving forth their efforts in their most eloquent 

 tongues have heard the commanding periods of 

 Pitt's majestic oratory the vehemence of Fox's 

 burning declamation have followed the close-com- 

 pacted chain of Grant's pure reasoning been carried 

 away by the mingled fancy, epigram, and argumenta- 

 tion of Plunket ; but I would without hesitation pre- 

 fer, for mere intellectual gratification (though aware 

 how much of it is derived from association), to be 



* See note, p. 26. 



