Page:Popular Science Monthly Volume 11.djvu/304

290 of living force and its preservation, but he does so for the most part quite mechanically, so that he appears to think no more about it than the beaver when he builds his hut. Man also does most things long before he understands them, and this is part of his nature. If he could make use of things only after having thoroughly investigated them, his life would be a poor one, and barely possible. If we had to study the functions of our clothing and its material before we could put it on, we should be frozen to death long before, and no carrier would have attempted to horse his cart before the time of Galileo and Newton,

Here I find myself drawing a dangerous parallel. You may ask me at once whether I believe a carrier will be a better carrier for understanding the laws of motion, and whether our clothing and our dwellings will one day be superior to what they are now, because we shall then have learned to understand their functions better. I leave the answer to the future with the utmost confidence. The experience of the past sets me completely at ease. At all times and everywhere it has been the case that each progress in the recognition of laws, that each new fact established, and each new method applied by science, each new way on which science has directed us, has finally had its practical and useful consequences. Excuse me if I continue to dwell on this favorite subject of mine.

What men call useful is quite a relative term; they call a thing so as soon as they find out what use they can make of it. Of course, a thing must exist before we recognize it, and we must become aware of certain of its properties and relations before we can make use of them for any practical purpose. Certainly the recognition of the laws of motion by Galileo, Kepler, Newton, Laplace, and others, has not brought about a revolution, or made a sensation among the carriers, but from these recognized laws sprang and were evolved new ideas, purified from the gross primitive slag, and they led on to the railway, etc. Other examples demonstrate still more clearly the connection between theory and practice.

Electric telegraphy, which is not only practical and useful, but already indispensable to us, had its first origin in the observations of the anatomist Galvani, who saw the legs of frogs quiver when they came in contact with different metals. Imagine to yourself great practical men of the time, whether statesmen, or divines, or soldiers, or physicians, witnessing Galvani's experiments going on year after year; certainly every one of them would have thought that the man could apply himself to something more useful. But from that form of electricity which Galvani detected there sprung the researches and works of Volta, Sömmering, Steinheil, Morse, and Wheatstone, to whom we owe the whole of our telegraphic system. Place together in your mind the quivering leg of the frog and the transatlantic cable.

After the-discovery of Columbus the Spaniards found in the sand