Cavendish,Henery (1731-1810)

was an English physicist and chemist who made fundamental discoveries in a number of scientific fields, although several of them remained unpublished in his lifetime. Cavendish was exceptionally brilliant but highly eccentric as well. In fact, Cavendish probably fit some of the "mad scientist" stereotypes. He almost totally avoided contact with other people, spoke very little, and went about in shabby clothing. But Cavendish possessed one of the most brilliant minds and conducted some of the most original experiments of his age. Cavendish did important experimental work in chemistry. He studied air and gases extensively. Cavendish was among the first scientists to recognize that hydrogen is a separate element. Experiments he conducted in 1784-1 785 led Cavendish to the conclusion that water is a compound of hydrogen and air (oxygen). The chemist Joseph Priestley had done the same experiments but had missed the importance of the water vapor produced when hydrogen and oxygen ignite. Cavendish also performed some experiments with carbon dioxide. Cavendish made fundamental discoveries in electricity. He anticipated the work of several later scientists, but most of his work on electricity went unpublished for years. Almost a century later, the English physicist James Clerk Maxwell recovered Cavendish's findings, publishing some of them in 1879. Cavendish discovered the law of electricity that later became known as Coulomb's law (and Coulomb's discovery). This law states that the force of two electrical charges is inverse to the square of the distance between them. Cavendish anticipated Ohm's Law as well by observing that the electrical potential across two conductors is directly proportional to the current between them. Cavendish also discovered that all points on the surface of a good conductor are at the same potential with respect to the earth. This idea proved very important later in the development of electrical theory. Cavendish had no instrument for measuring electrical current. He used his own body as a meter, grasping an electrode with each hand and then judging how far from his fingertips the shock spread. Henry Cavendish was born in Nice, France, a descendant of the Duke of Devonshire and the Duke of Kent. He attended Cambridge University but did not obtain a degree. For many years Cavendish lived with his father, also a distinguished scientist, in London. The two Cavendishes performed many experiments together. Henry's father died in 1783. Henry Cavendish was elected to the Royal Academy in 1760. He became a foreign associate of the Institute of France in 1803. Cavendish possessed an enormous fortune, which he left to family members at his death in 1810. Many years later, in 1871, the Cavendish family endowed the Cavendish Laboratory at Cambridge, where many of the modern discoveries in physics have been made.