Franklin as a scientist[13] and as an inventor has been decried by experts as an amateur and a dabbler; but it should be remembered that it was always his hope to retire from public life and devote himself to science. In the American Philosophical Society (founded 1743) scientific subjects were much discussed. Franklin wrote a paper on the causes of earthquakes for his _Gazette_ of the 15th of December 1737; and he eagerly collected material to uphold his theory that waterspouts and whirlwinds resulted from the same causes. In 1743, from the circumstance that an eclipse not visible in Philadelphia because of a storm had been observed in Boston, where the storm although north-easterly did not occur until an hour after the eclipse, he surmised that storms move _against_ the wind along the Atlantic coast. In the year before (1742) he had planned the "Pennsylvania fire-place," better known as the "Franklin stove," which saved fuel, heated all the room, and had the same principle as the hot-air furnace; the stove was never patented by Franklin, but was described in his pamphlet dated 1744. He was much engaged at the same time in remedying smoking chimneys, and as late as 1785 wrote to Jan Ingenhousz, physician to the emperor of Austria, on chimneys and draughts; smoking street lamps he remedied by a simple contrivance. The study of electricity he took up in 1746 when he first saw a Leyden jar, in the manipulation of which he became expert and which he improved by the use of granulated lead in the place of water for the interior armatures; he recognized that condensation is due to the dielectric and not to the metal coatings. A note in his diary, dated the 7th of November 1749, shows that he had then conjectured that thunder and lightning were electrical manifestations; in the same year he planned the lightning-rod (long known as "Franklin's rod"), which he described and recommended to the public in 1753, when the Copley medal of the Royal Society was awarded him for his discoveries. The famous experiment with the kite, proving lightning an electrical phenomenon, was performed by Franklin in June 1752. He overthrew entirely the "friction" theory of electricity and conceived the idea of plus and minus charges (1753); he thought the sea the source of electricity. On light Franklin wrote to David Rittenhouse in June 1784; the sum of his own conjectures was that the corpuscular theory of Newton was wrong, and that light was due to the vibration of an elastic aether. He studied with some care the temperature of the Gulf Stream. In navigation he suggested many new contrivances, such as water-tight compartments, floating anchors to lay a ship to in a storm, and dishes that would not upset during a gale; and beginning in 1757 made repeated experiments with oil on stormy waters. As a mathematician he devised various elaborate magic squares and novel magic circles, of which he speaks apologetically, because they are of no practical use. Always much