the useful and the practical which does not tend to exalt the scientific man in the opinion of the public. Even the great leaders in science have been misrepresented in this matter. Because they wisely determined in many instances to leave to others the task of developing the practical applications of their discoveries, it has often been represented that they held such applications as unworthy a true man of science. As illustrating the injustice of such an opinion, one may cite the case of the most brilliant philosopher of his time, Michael Faraday, who in the matter of his connection with the Trinity House alone gave many of the best years of his life to the service of his fellow-men. The intensely "practical" nature of this service is shown by the fact that it included the ventilation of lighthouses, the arrangement of their lightning conductors, reports upon various propositions regarding lights, the examination of their optical apparatus, and testing samples of cotton, oils, and paints. A precisely similar illustration is to be found in the life of our own great physicist, Joseph Henry, who sacrificed a career as a scientific man, already of exceptional brilliancy, yet promising a future of still greater splendor, for a life of unselfish usefulness to science and to his countrymen, as Secretary of the Smithsonian Institution, as a member of the Lighthouse Board, and in other capacities for which he was especially fitted by nature as well as by his scientific training.
There is an unfortunate and perhaps a growing tendency among scientific men to despise the useful and the practical in science, and it finds expression in the by no means uncommon feeling of offended dignity when an innocent layman asks what is the use of some new discovery.
Referring to the theoretically extremely interesting spar prism of Bertrand, which under certain conditions may be used to detect traces of polarization of light, a recent writer remarks, "But for this application the prism would possess, in the eyes of the true votary of science, the inestimable value of being of no practical utility whatever."
Much is said, everywhere and at all times, about the pursuit of science for the sake of science; and on every hand it is sought to convey the impression that one who has any other object in view in interrogating Nature than the mere pleasure of listening to her replies, is unworthy of a high place among men of science. So old, so universally accepted, so orthodox, is this proposition, that it is with much hesitation that its truth is questioned in this presence. In so far as it means that one can not do anything well unless it is done con amore, that pecuniary reward alone will never develop genius, that no great philosopher or poet or artist will ever be other than unselfishly devoted to and in love with his work, just so far it is true, although it does not, as is often as,