Cornelis Drebbel (1572-1633) (Tierie, G.)

This is a biography of a great inventor who failed to be a great scientist because he was not independently wealthy (like Robert Boyle and Christiaan Huygens). Like other inventors and artists of his day he was largely dependent upon the favor of princes, and was obliged to do everything in his power to maintain his position at court. He was forced to wrap his inventions in secrecy and to say very little about his theories. Drebbel studied the effect of pressure and temperature on the volume of air, and in 1598 took out a patent for an automatic pump and for a clock which did not need winding—both of them being operated by the variations in the volume of a confined quantity of air. In 1600 he built a fountain at Middleburg which operated on the same principle; in 1605 while in England he built his perpetuum mobile for James I at Eltham; and in 1610 while in Bohemia he built another fountain for Rudolf II at Prague. The perpetuum mobile in its simplest form consisted of a glass bulb attached to a spiral of glass tubing in which there was a small quantity of liquid. The gas in the bulb, expanding by day and contracting by night, produced an ebb and flow of the liquid in the spiral tube. There is some evidence which indicates that Drebbel perhaps filled his bulb with oxygen gas procured by the heating of saltpeter. On the same principle he constructed selfregistering ovens and incubators for the hatching of chicks. He was expert in the manufacture, blowing, and grinding of glass, and invented an ingenious machine for the grinding of lenses. His camera obscura attracted much attention from artists and savants. He is credited with the invention of the microscope with two convex lenses. Drebbel won much fame with his submarine or diving-boat in which he went under water down the Thames for a considerable distance in the presence of James I and Ins court. The boat had no bottom and was constructed on the principle of the diving bell. He measured his depth under water by means of a mercury barometer, steered by means of a compass, and renewed the goodness of the air confined in the boat by the use of a gas made from saltpeter, "broken up by the power of fire and so changed in the nature of air.” He believed that air is made up of two component parts, the quintessence (oxygen), fit for respiration, and the carcass (nitrogen), unfit for respiration. Soon after his arrival at the English court, Drebbel helped to arrange a fireworks display. Later he devoted himself to the preparation of fulminating gold, a substance which he possibly discovered, which he used in 1628 before La Rochelle as a detonator in his petards and torpedoes. He was the first to use tin salt