It is a very great pity that we know no more about these earliest submarines. Cornelius Van Drebel died in 1634, at the age of sixty-two, without leaving any written notes or oral descriptions. We must not think too hardly of this inventor of three centuries ago, unguarded by patent laws, for making a mystery of his discoveries. He had to be a showman as well as a scientist, or his noble patrons would have lost all interest in his “ingenious machines,” and mystery is half of the showman’s game. Besides his “eel-boats,” Van Drebel is said to have invented a wonderful globe with which he imitated perpetual motion and illustrated the course of the sun, moon, and stars; an incubator, a refrigerator, “Virginals that played of themselves,” and other marvels too numerous to mention. Half scientist, half charlatan, wholly medieval in appearance, with his long furred gown and long, fair beard, Cornelius Van Drebel marches picturesquely at the head of the procession of inventors who have made possible the modern submarine. Eighteen years after Van Drebel’s death, a Frenchman named Le Son built a submarine at Rotterdam. This craft, which is usually referred to as the _Rotterdam Boat_, was 72 feet long, 12 feet high, and of 8 foot beam. It was built of wood, with sharply tapering ends, and had a superstructure whose sloping sides were designed to deflect cannon balls that might be fired at the boat while traveling on the surface, while iron-shod legs protected the hull when resting on the sea bottom. A single paddle-wheel amidships was to propel the boat,--just how, the inventor never revealed. Like so many other submarines, the _Rotterdam Boat_ was built primarily to be used against the British fleet. But it failed to interest either the Dutch or French minister of marine, and never went into action. The earliest known contemporary picture of a submarine vessel appeared in the “Gentleman’s Magazine,” in 1747. It showed a cross section of an underwater boat built and navigated on the Thames by one Symons. This was a decked-over row-boat, propelled by four pairs of oars working in water-tight joints of greased leather. To submerge his vessel, Symons admitted water into a number of large leather bottles, placed inside the hull with their open mouth passing through holes in the bottom. When he wished to rise, he would squeeze out the water with a lever and bind up the neck of each emptied bottle with string. This ingenious device was not original with Mr. Symons, but was invented by a Frenchman named Borelli in 1680.