DREBBEL, CORNELIS (JACOBSZOON)

born 1572, Alkmaar, Neth. died Nov. 7, 1633, London Dutch inventor who built the first navigable submarine. An engraver and glassworker in Holland, Drebbel turned to applied science and in 1604 went to England, where King James I became his patron. He devised an ingenious perpetual motion clock, actuated by changes in atmospheric pressure and temperature, which greatly enhanced his reputation. In 1620 he completed his diving boat. Propelled by oars and sealed against the water by a covering of greased leather, the wooden vessel travelled the River Thames at a depth of 12 to 15 feet (about 4 metres) from Westminster to Greenwich. Air was supplied by two tubes with floats to maintain one end above water. Drebbel also discovered the use of tin compounds as mordants for cochineal, a scarlet dye, and suggested a method of making sulfuric acid by the oxidation of sulfur. Among many other inventions attributed to him are the compound microscope, an improved thermometer, and self-regulating ovens.