PRESIDENTIAL ADDRESS. 13 



He seemed extremely fond, through the course of the visit, of 

 dwelling on philosophical subjects, and particularly that of natu- 

 ral history, while the other gentlemen were swallowed up in poli- 

 tics. This was a favorable circumstance to me, for almost all his 

 conversation v/as addressed to me, and I was highly delighted 

 with the extensive knowledge he appeared to possess of every 

 subject, the brightness of his faculties, the clearness and vivacity 

 of his mental powers, and the strength of his memory, notwith- 

 standing his age. His manners are perfectly easy, and everything 

 about him seems to diffuse an unrestrained freedom and happi- 

 ness. He has an incessant vein of humor, accompanied with an 

 uncommon vivacity that seems as natural and involuntary as his 

 breathing." 



To Franklin, as President of the Philosophical Society, suc- 

 ceeded David Rittenhouse [b. 1732, d. 1796], a man of world-wide 

 reputation, known in his day as " the American Philosopher."* 



He was an astronomer of repute, and his observatory built at 

 Norriton in preparation for the transit of Venus in 1769 seems to 

 have been the lirst in America. His orrery, constructed upon an 

 original plan, was one of the wonders of the land. His most 

 important contribution to astronomy was the introduction of the 

 use of spider lines in the focus of transit instruments.! 



He was an amateur botanist, and in 177^ made interesting 

 physiological experiments upon the electric eel. J 



He was a Fellow of the Royal Society of London, and the 

 first Director of the United States Mint. 



Next in prominence to Franklin and Rittenhouse were doubt- 

 less the medical professors, Benjamin Rush, William Shippen, 

 John Morgan, Adam Kuhn, Samuel Powell Griffiths, and Cas- 

 par Wistar, all men of scientific tastes, but too busy in pub- 

 lic aflairs and in medical instruction to engage deeply in research, 

 for Philadelphia, in those days as at present, insisted that all 



* See obituary in the European Magazi)ic, July, 1796; also Memoiis 

 of Rittenhouse, by William Barton, 1813, and Eulogium by Benjamin 

 Rush, 1796. 



t Von Zach : Monatliche Correspondenz, ii, p. 215. 



J Phila. Medical Repository, vol. i. 



