Henry Cavendish is probably best known for his discovery in 1766 of "inflammable air", which eventually came to be called hydrogen gas. He was the first person to realize that the combustion of hydrogen yields water. He explained this saying that water is hydrogen minus phlogiston. In 1772, he independently discovered nitrogen, but credit is usually given to Daniel Rutherford. Also of interest, Cavendish determined the mass of the Earth in 1798.