Gas

(gaz) [a word coined by the Belgian chemist, Yan Helmont]. An air-like fluid. The word is especially applied to those fluids that under normal conditions are aeriform; while those that can be readily condensed to liquids are termed vapors. G., Laughing, nitrous oxid. G., Marsh, methane. G., Olefiant, ethylene. G., Permanent, a term formerly applied to those gases, as ox}-gen, nitrogen, hydrogen, that were thought non liquefiable. 292