The nature of hydrogen began to emerge around the 16th century when F. B. Paracelsus first described a gaseous product arising when iron was dissolved in sulfuric acid. He described this product as "an air which bursts forth like the wind".
Van Helmot described this gas as a special kind of air, which was combustible but could not support combustion. However, his ideas were quite fuzzy, since he confused hydrogen with other gases that could not also support combustion like methane or carbon dioxide.
Priestley, and in general all the authors until 1783, used the term inflammable air to describe this gas as to hidrocarbons, hydrogen sulphite, carbon monoxide and other combustible gases.
H. Cavendish (1766) showed that the inflammable air produced by the acid action on metals like iron, zinc or tin was a distinct and well defined substance. A. L. Lavoisier (1783) called this substance "hydrogen".