Hydrogen was recognized as a distinct substance by the English chemist, Henry Cavendish, in 1766, but had been prepared in the sixteenth century by the Swiss alchemist, Theophrastus Bombastus von Hohenheim, otherwise known as Paracelsus, by the action of acid on certain metals. The gas was named by Antoine-Laurent Lavoisier, a French chemist, in 1781.
Hydrogen, along with helium, is the most ancient of the elements. In the early universe, hydrogen and helium accounted for almost all matter, and their reactions, in the centres of stars, produced the heavier elements. Today, hydrogen is still the most abundant element in the universe, accounting for 90% of all atoms and 75% of all mass.
Being the lightest of the elements, hydrogen was once used to inflate balloons. Hydrogen-filled balloons were used from 1783 to the middle of the twentieth century, but the high flammability of the gas led to a number of explosions and its eventual replacement by helium. The Hindenburg, a hydrogen-filled airship, exploded in Lakewood, New Jersey, in 1937.
