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SCIENCE. 



[N. S. Vol. II. No. 43. 



as in the lives of so many English men of 

 science. Brought together in the world's 

 metropolis, we read not so much of isolated 

 reflections in the quiet study as of familiar in- 

 tercourse in the brotherhood of congenial tastes. 

 After the death of Banks, in 1820, Rennell was 

 the acknowledged head of English geographers. 

 Travellers and explorers came to him with their 

 rough work, projects were submitted for his 

 opinion, reports were sent to him from all parts 

 of the world. The Raleigh Club was formed in 

 1827, ' for the attainment at a moderate ex- 

 pense, of an agreeable, friendly and rational 

 society, formed by persons who had visited all 

 parts of the world.' After Rennell' s death the 

 formation of a Geographical Society to supply 

 his place became a necessity, and thus largely 

 from his impulse was founded what has become 

 the greatest force in geography to-day. Explo- 

 ration rather than explanation was then natur- 

 ally the direction of earth study ; and it is 

 chiefly in this division of geography that the 

 English still follow their leader. W. M. D. 



Oeuvres ophialmologiques de Thomas Young, tra- 

 duites et annotees par M. Tscheening, prece- 

 dees du portrait de Young, de son 61ogue par 

 Frangois Arago et d'une preface par Emile 

 Javal. Publication faite aux frais de la 

 Fondation Carlsberg. Copenhague, Host et 

 Son. 1894. 80 pp. x+248. 

 Among the great men who have inaugurated 

 important epochs in science there are two classes; 

 the first, writing with a fertile imagination and 

 extraordinary capacity for work, have devel- 

 oped one or more kindred ideas and have 

 achieved results of great perfection ; the second 

 class, while endowed with imagination no less, 

 or perhaps even more powerful, have, in the ab- 

 sence of persistent, concentrated effort, followed 

 the caprices of an intellectual curiosity which 

 led in divers directions, and the works of their 

 genius which have been preserved are conse- 

 quently less perfect both in form and substance. 

 Their writings are often intricate and obscure ; 

 but this very complexity not infrequently in- 

 vests them with a peculiar charm for the 

 thinker. 



The most distinguished of the first tj^e of 

 mind was Isaac Newton : the most remarkable 



of the second tj-pe was Thomas Young. New- 

 ton turned all the efforts of his genius toward 

 mathematics and physics. To facts carefully 

 observed he applied the powerfiil aid of the cal- 

 culus and gave one of the finest examples of the 

 fecundity of the mathematical method. The 

 works of Laplace, Ampere, Cauchy and, in a 

 certain measure, those of Fresnel are the pro- 

 duct of a similar spirit. Works of this class are 

 usually crowned with recognition and honors 

 during the lifetime of their authors ; for sooner 

 or later, by the force of logic, they are able to 

 rise above the never-failing hostile coalitions of 

 mental inertia and the vanity of mediocrity in 

 power. The same good fortune, however, is 

 not the part of such works as those of Thomas 

 Young. Mathematician, physicist, naturalist, 

 physician, philologist and engineer, he has left 

 profound traces of his originality in each of 

 these domains ; yet in not one of them was his 

 genius recognized by his contemi:)oraries. En- 

 dowed with extraordinary intuitive power, he 

 was able to assimilate with marvellous rapidity 

 the most varied kinds of knowledge, the conse- 

 quence of which marks all his writings with a 

 conciseness of language and exposition which, 

 for the ordinary student accustomed to long and 

 minute reasoning, gives to them an obscurity 

 ofttimes discouraging. 



The complications of Nature are infinite, and 

 never in her manifold manifestations does she 

 take into account the categories among which 

 our intelligence is forced to divide itself up both 

 in methods and reasoning. There is not a phe- 

 nomenon in the animate world which has not 

 its characteristics at once physico-chemical and 

 mathematical ; and the stating of biological 

 problems in the form of problems in physics 

 accessible to mathematical calculation is always 

 attended with great difficulty. Young treated 

 biological problems, especially those of ophthal- 

 mology, in this spirit, which was not then, and 

 is not now, that of the medical profession. As a 

 natvxral result he was not understood by his, con- 

 freres, or was understood only sufficiently to be 

 considered their adversary ; an attitude by no 

 means calculated to enhance his scientific popu- 

 larity. He had besides the honor of being able 

 to furnish an elegant interpretation of the curi- 

 ous phenomenon of the coloration of soai>-bub- 



