Cavendish and other investigators conducting an experiment to determine the speed of electricity. Henry Cavendish (October 10, 1731 - February 24, 1810) was an English natural philosopher, scientist, and an important experimental and theoretical chemist and physicist. He described the density of Hydrogen (inflammable air), which formed water on combustion, in a 1766 paper "On Factitious Airs". Lavoisier later reproduced Cavendish's experiment and gave the element its name. Cavendish distinguished for great accuracy and precision in his researches into the composition of atmospheric air, the properties of different gases, the synthesis of water, the law governing electrical attraction and repulsion, a mechanical theory of heat, and calculations of the density (and hence the weight) of the Earth. His experiment to weigh the Earth has come to be known as the Cavendish experiment. He was a shy man who was uncomfortable in society and avoided it when he could. Contemporary accounts of his personality have led some modern commentators to speculate that he had Asperger syndrome, though he may merely have been anthropophobic. He died in 1810 at the age of 78.