Franklin deserves mention not only in connection with economics, meteorology, practical ethics, electricity, and pedagogy; his biographer enumerates nineteen sciences to which he made original contributions or which he advanced by intelligent criticism. In medicine he invented bifocal lenses and founded the first American public hospital; in navigation he studied the Gulf Stream and waterspouts, and suggested the use of oil in storms and the construction of ships with water-tight compartments; in agriculture he experimented with plaster of Paris as a fertilizer and introduced in America the use of rhubarb; in chemistry he aided Priestley's experiments by information in reference to marsh gas. He foresaw the employment of air craft in war. Thinking the English slow to take up the interest in balloons, he wrote that we should not suffer pride to prevent our progress in science. Pride that dines on vanity sups on contempt, as Poor Richard says. When it was mentioned in his presence that birds fly in inclined planes, he launched a half sheet of paper to indicate that his previous observations had prepared his mind to respond readily to the discovery. His quickness and versatility made him sought after by the best intellects of Europe. I pass over his analysis of mesmerism, his conception of light as dependent (like lightning) on a subtle fluid, his experiments with colored cloths, his view of the nature of epidemic colds, interest in inoculation for smallpox, in ventilation, vegetarianism, a stove to consume its own smoke, the steamboat, and his own inventions (clock, harmonica, etc.), for which he refused to take out patents. However, from the many examples of his scientific acumen I select one more. As early as 1747 he had been interested in geology and had seen specimens of the fossil remains of marine shells from the strata of the highest parts of the Alleghany Mountains. Later he stated that either the sea had once stood at a higher level, or that these strata had been raised by the force of earthquakes. Such convulsions of nature are not wholly injurious, since, by bringing a great number of strata of different kinds today, they have rendered the earth more fit for use, more capable of being to mankind a convenient and comfortable habitation. He thought it unlikely that a great _bouleversement_ should happen if the earth were solid to the center. Rather the surface of the globe was a shell resting on a fluid of very great specific gravity, and was thus capable of being broken and disordered by violent movement. As late as 1788 Franklin wrote his queries and conjectures relating to magnetism and the theory of the earth. Did the earth become magnetic by the development of iron ore? Is not magnetism rather interplanetary and interstellar? May not the near passing of a comet of greater magnetic force than the earth have been a means of changing its poles and thereby wrecking and deranging its surface, and raising and depressing the sea level?