THE century's GREAT MEN TN SCIENCE. 697 



relatives into existence, which revolutionizes general conceptions of 

 reasoning. The works of Comte, Whewell, J. S. Mill, Jevons, and 

 others upon the philosophy of inductive science were less successful 

 or fruitful. In the more metaphysical part of logic the philosophy of 

 Hegel, though it can not be accepted on the whole, was the work of a 

 great man. In metaphysics and general cosmology the attitude of the 

 century has been expectant. Herbert Spencer has been proclaimed 

 as a sort of scientific Messiah by a group of followers more ardent than 

 philosophic, which does not seem to be gathering strength. 



At the head of the physical sciences stands nomological physics. 

 Dr. Thomas Young was here the earliest great man of the century, 

 whose intellect illuminated every corner to which it was directed, 

 taking the first difficult steps in the decipherment of the hieroglyphics, 

 originating the doctrine of color-mixtures, propounding the correct 

 th(M)ry of light, and illuminative everywhere. It gives a realizing 

 sense of the century's progress that this great man in its early years 

 should have opined that experimentation in general had then been 

 pushed about far enough. On that occasion it was not his usual logic, 

 but the eighteenth-century watchword " le bon sens,'' that was his 

 guide, with the sort of result it is continually turning out when used 

 beyond its proper sphere of every-day practical affairs. The advance 

 of 3'ears, with their experience, has led physicists to expend more and 

 vastly more effort upon extreme precision, against every protest of 

 good sense. What has come of it? Marconi's wireless telegraphy, 

 for one thing. For it was the precision with which the velocity of 

 light on the one hand and the ratio of statical and dynamical constants 

 of electricity on the other had been determined that proved to Max- 

 well that the vibrating medium of light was the substance of electric- 

 ity, a theory that his great follower. Hertz, applied to making giant 

 light waves less affected by obstructions than even those of sound. I 

 dare say, sapient ''good sense'' pooh-poohs those wonderful new sul)- 

 stances, helium and the rest, that seem the connecting link between 

 ordinary matter and the ether. So it would be useless to point out 

 t'hat their discovery was entirely due to Lord Kayleigh's fastidious- 

 ness in the determination of the density of nitrogen. But it has to be 

 noted as a characteristic of the great physicists of the nineteenth cen- 

 tury that their reverence for every feature of the phenomenon, how- 

 ever minute, has been in thorough disaccord with the older "good sense." 

 The greatest advances in physics during the century were made by 

 several men at once. Certain ideas would come somehow to be in the 

 air; and by the time they had crystalized for a student here and there, 

 he would hesitate to announce as original conceptions what he had 

 reason to suppose manv men shared, while he knew that the larger 

 bodv would not be yet ready to accept them. Under those circum- 

 stances priority of publication can signify nothing except haste. 

 SM 1900 48 



