Jean Baptiste von Helmont (1579-1644). Belgian physician and chemist. Helmont recognised that there are more gases than just air, and claimed to have coined the word 'gas'. He believed that all mater was composed of water and air, and to prove this he grew a willow tree in earth, adding only water. From Vies des Savants lllustres by Louis Figuier. (Paris, 1870). Engraving.