Mr. Prime Minister," answered Faraday, "you will soon be able to tax it." On another occasion, in reply to a similar question from an elderly lady, he quoted Benjamin Franklin, "Madam, of what use is a new-born child?"
The seemingly useless knowledge about the laws of force and motion developed by Galileo and Newton and first applied to the seemingly useless matters of the motions of the heavenly bodies was the essential basis for the design of power machines of every sort as well as for many other things. This knowledge preceded the steam-engine, a century of experience with which led to a knowledge of the laws of heat engines in general, which was essential to the development of the internal combustion engine, which in turn made the airplane possible although this outcome was in no way predictable. Leonardo da Vinci is said to have devoted far more time to the problem of flying than he did to painting, but it was necessary to wait several centuries before the development of the gasoline engine, primarily for use in automobiles, made flying possible. Thus the solution of one problem very often has to await the solution of another with which it did not seem to be connected.
The radio and the arts based upon it, today involving commercial values running into billions, are even younger than the automobile, the whole industry having developed since 1910 upon the basis of investigations in pure science principally done on the seemingly useless problem of electronic discharges in high vacuum. The perfection of glass technology made possible the Michelson interferometer, which in turn resulted in an experiment that formed the basis of Einstein's theory, a theory which has revolutionized not only our understanding of physics, but also our entire philosophy. As to research on seemingly useless biological subjects, Professor Thomson says: "A few years ago zoologists were laughed at who solemnly counted the hairs on the backs of flies and quarreled over the specific distinctions between one gnat and another. And could there be for able-bodied men a waste of time more scandalous than cutting sections of entrails of ticks? Yet it has been this sort of knowledge of flies and gnats and ticks that made it possible to open up Africa and complete the Panama Canal." In unforseen ways every truth seems sooner or later to find its application.
APPLICATIONS OF SCIENCE
Every new invention tends to generate a new industry giving employment to large numbers of men. Think for a moment of the development within the last 30 years of the industries based upon such inventions as the automobile, the airplane, the motion picture, the radio, and rayon, employing together 10,000,000 men or more. The automobile was unknown except as a costly toy before the turn of the century. Today there are 30,000,000 motor vehicles on the roads of the United Stales alone. Within four decades it has
