English scientist and inventor, b. Nice, France 1731-10-10, d. London, England 1810-02-24. His beginnings in science came from work he did with his father, who was a decent enough scientist in his own right, even earning the acclaim of Benjamin Franklin.
Cavendish was one of the classic "mad scientists" of his time. He never completed his studies at Cambridge but inherited an enormous fortune (being the grandson of the second Duke of Devonshire, money ran in the family) that would support his scientific "habit." He lived a secluded life and forbade the female staff to be seen by him, threatening any who did with dismissal. Meals were ordered through little notes left on the hall table. He kept his own library outside the premises in order to avoid running into other people who may have come to consult it. He also had the bad habit of keeping his notes to himself and later referring to them in work he actually published.
Eccentricity aside, his scientific reasoning was sounder than his social graces. He is credited with the discovery of hydrogen and the fact that water was a combination of two gases--hydrogen and oxygen. Although he subscribed to the myth of phlogiston, he used it to conduct and document a number of chemical and electrochemical reactions, for which the observations are essentially sound. He did a lot of basic work to establish the freezing points and boiling points of various substances and aqueous solutions and experimented with electrolytes, as well as the physical properties of many other substances.
Another one of his remarkable works was the accurate calculation of the earth's density and the measurement of Newton's gravitational constant. He also established that the ratio of nitrogen to oxygen in the atmosphere was roughly 4 to 1. Some of the most important electrical discoveries he made were never published by him but made Coulomb and Ohm household names in the world of physics. Prominent physicists like Michael Faraday and James Maxwell stood on his shoulders. In fact, we owe much of Cavendish's work to Maxwell who rescued his notes and published them.
The Cavendish Laboratory at Cambridge bears his name, making him one of the few dropouts to be thus highly honoured by any university but only after his family endowed the university with a significant sum 66 years after his death.
Factual sources:
Encyclopaedia Britannica
Carmen Giunta, Le Moyne College
Peter Landry