1886.] on Thomas Young. 669 



plete and impressive than any ever exhibited by the rainbow in nature. 

 Many of you are acquainted with the beautiful rings of colour ob- 

 served when a point of light is looked at through the seeds of lycopo- 

 dium shaken over a piece of glass, or shaken in the air so as to form a 

 cloud whose particles are all of the same size. The iridescence of 

 clouds that I have once or twice seen in great splendour in the Isle 

 of Wight, but more frequently in the Alps, is due to this equality 

 in the size of the cloud-particles. Now the smaller the particles, the 

 wider are the coloured rings, and Young devised an instrument called 

 the Eriometer, which enabled him, from the measurement of the rings, 

 to infer the size of the particles. Again, Bitter had discovered the ultra- 

 violet rays of the spectrum, while Wollaston had noticed the darken- 

 ing effect produced by these rays when permitted to fall on paper or 

 leather which had been dipped in a solution of muriate of silver. 

 Employing these invisible rays to produce invisible Newton's rings, 

 Young projected an image of the rings upon the chemically prepared 

 paper. He thus obtained a distinct photographic image of the rings. 

 This was one of the earliest experiments wherein a true photographic 

 picture was successfully obtained. Young had little notion at the 

 time of the vast expansions which the art of photography was sub- 

 sequently to undergo. 



But Young was not permitted to pursue his great researches in 

 peace. The ' Edinburgh Eeview ' had at that time among its chief 

 contributors a young man of vast energy of brain and vast power of 

 sarcasm, without the commensurate sense of responsibility which 

 might have checked and guided his powers. His intellect was not 

 for a moment to be measured with that of Young ; but as a writer 

 appealing to a large class of the public, he was, at that time, an 

 athlete without a rival. He afterwards became Lord Chancellor 

 of England. Young, it may be admitted, had given him some 

 annoyance, but his retaliation, if such it were, was out of all pro- 

 portion to Young's offence. Besides, whatever his personal feelings 

 were, it was not Young that he assailed so much as those sublime 

 natural truths of which Young at the time was the foremost exponent. 

 Through the undulatory theory he attacked Young without scruple or 

 remorse. He sneered at his position in the Koyal Institution, and tried 

 hard to have his papers excluded from the ' Philosophical Transac- 

 tions.' " Has the Eoyal Society," he says, " degraded its publications 

 into bulletins of new and fashionable theories for the ladies of the 

 Eoyal Institution ? Let the Professor continue to amuse his audience 

 with an endless variety of such harmless trifles, but in the name of 

 science let them not find admittance into that venerable repository which 

 contains the works of Newton and Boyle and Cavendish and Maskelyne 

 and Herschel." The profound, complicated and novel researches on 

 which Young was then engaged, rendered an occasional change of 

 view necessary. How does the reviewer interpret this praiseworthy 

 loyalty to truth ? " It is difficult," he says, " to deal with an author 



