SKETCH OF LORD RAY LEIGH. 841 



in the next place, the nobleman who presided at Montreal is not 

 merely a lord, but a man of very distinguished ability and eminently 

 entitled to the honor from both the character and extent of his ori- 

 ginal scientific work. His writings, however, are only or chiefly 

 known to scientific men. Numerous papers from his pen are scattered 

 through the pages of the proceedings of several learned societies of 

 England, though some of them have been collected into a volume 

 and published separately. He has produced but one extensive work, 

 namely, " The Theory of Sound," a mathematical treatise in two vol- 

 umes. It was begun on the Nile in 1872, and published in 1877-78. 

 The article on "Optics," in the last volume of the "Encyclopaedia 

 Britannica," was also written by him. His determinations of the 

 ohm, which were presented to the Paris Conference of Electricians 

 in 1883-'84, have been accepted as the basis of the unit of electrical 

 resistance. His recent experiments in methods of practically measur- 

 ing the strength of the electric current point to the method, by the 

 deposition of silver, as one capable of furnishing a high degree of 

 accuracy. 



To these scanty particulars of Lord Rayleigh's life and career, for 

 which we are mainly indebted to a brief sketch in the Montreal " Star," 

 we may add the estimate of his work given by Sir William Thomson 

 in introducing him to the large audience at the first assemblage of the 

 Association in Montreal, August 27th, when he assumed the presi- 

 dential chair. Referring first to the work of his predecessor, Sir Will- 

 iam Thomson remarked : " Professor Cayley has devoted his life to 

 the advancement of pure mathematics. It is indeed peculiarly appro- 

 priate that he should be followed in the honorable post of president 

 by one who has done so much to apply mathematical power in the 

 various branches of physical science as Lord Rayleigh has done. In 

 the field of the discovery and demonstration of natural phenomena 

 Lord Rayleigh has, above all others, enriched physical science by the 

 application of mathematical analysis ; and when I speak of mathe- 

 matics you must not suppose mathematics to be harsh and crabbed. 

 (Laughter.) The Association learned last year at Southport what a 

 glorious realm of beauty there was in pure mathematics. I will not, 

 however, be hard on those who insist that it is harsh and crabbed. 

 In reading some of the pages of the greatest investigators of mathe- 

 matics one is apt occasionally to become wearied, and I must confess 

 that some of the pages of Lord Rayleigh's work have taxed me most 

 severely, but the strain was well repaid. When we pass from the 

 instrument which is harsh and crabbed to those who do not give them- 

 selves the trouble to learn it thoroughly, to the application of the in- 

 strument, see what a splendid world of light, beauty, and music is 

 opened to us through such investigations as those of Lord Rayleigh! 

 His book on sound is the greatest piece of mathematical investigation 

 we know of applied to a branch of physical science. The branches of 



