Marsh Gas
in chemistry, CH₁= CH3, methane; light carburetted hydrogen, hydride of methyl, a hydrocarbon gas very abundant in nature. It is evolved from stagnant water, and great quantities are given off in coal pits where it is known as the fire damp of the miners. It is one of the usual products of the destructive distillation of organic matters. It may be formed in large quantities by the destructive distillation of a mixture of alkaline acetate with a hydrated alkali. Of all known compounds it is the richest in hydrogen, and, with the exception of the latter, is the lightest known gas (sp. gr. .5576, air=1). It is colorless, without taste or smell, and is neutral to test paper.