562 Professor Tijndall [Jan. 22, 



he never spoke in praise of any of the writers of the day, and could 

 not be persuaded to discuss their merits. He would speak of know- 

 ledge in itself — of what was known or what might be known, but 

 never of himself or of any one else, as having discovered anything, or 

 as likely to do so. His language was correct, his utterance rapid, 

 but his words were not those in familiar use, and he was therefore 

 worse calculated than any man I ever knew for the communication of 

 knowledge." This writer heard Young lecture at the Eoyal Institution, 

 but thought that nothing could show less judgment than the method 

 he adopted. " It was difficult to say how he employed himself at 

 Cambridge. He read little ; * there were no books piled on his floor, 

 no papers scattered on his table. His room had all the appearance 

 of belonging to an idle man. He seldom gave an opinion, and never 

 volunteered one ; never laid down the law, like other learned doctors, 

 or uttered sayings to be remembered. He did not think abstractedly. 

 A philosophical fact, a difficult calculation, an ingenious instrument, 

 or a new invention, would engage his attention ; but he never spoke 

 of morals, or metaphysics, or religion. Of the last, I never heard him 

 say a word. Nothing in favour of any sect or in opposition to any 

 doctrine." 



The impression made upon Young by Cambridge was, from first 

 to last, entirely favourable. In those days, six years' study were 

 indispensable before the degree of Bachelor of Medicine could be 

 taken. Young graduated in 1803, when he was thirty years of age, 

 and five years more had to elapse before he could take the degree of 

 M.D. Meanwhile he had begun the practice of medicine. Dr. 

 Brocklesby died, in 1797, on the night of a day when he had 

 entertained his nephew and some other friends at dinner. During 

 dinner he seemed perfectly well, but he expired a few minutes 

 after he went to bed. He left Young his house and furniture in 

 Norfolk Street, Park Lane, his library, his j^rints, a collection of 

 pictures chiefly selected by Sir Joshua Reynolds, and about 10,000/. 

 in money. 



The Wave Theory. 



On the IGth of January, 1800, Young communicated to the Royal 

 Society his memoir entitled " Outlines and Experiments respecting 

 Sound and Light." In this paper he treated of the interference of 

 sound, and his researches on this subject led him on to the discovery 

 of the interference of light — " Which has proved," says Sir John 

 Herschel, " the key to all the more abstruse and puzzling i)roperties 

 of light, and which would alone have sufficed to place its author in 

 the highest rank of scientific immortality, even were his other almost 

 innumerable claims to such a distinction disregarded." Newton con- 

 sidered the sensation of light to be aroused by the darting into the 



* Critics aud commentators must be f^ircat readers ; but creators in scionoe 

 and philosoi^hy do not always belong to this cntegory. 



