A gas consisting mainly of carbon monoxide and hydrogen, made by passing steam over red-hot coke and burning with a blue flame, used especially as a source of hydrogen; also called Blue gas, Water gas. The manufacture of water gas first became an industrial proposition in 1873 with the introduction of the intermittent system by Strong and by Lowe in the United States. Strong, who aimed at manufacturing blue water gas mainly for heating purposes., utilised the heat value of the “blow” gases to superheat the steam admitted to the generator. Lowe, on the other hand, aimed at producing a gas of high illuminating value, and utilised the large quantities of combustible gas produced during the “blow” periods for heating chambers in which enriching oil was decomposed. No real progress in the manufacture of water gas in Great Britain was made until 1888,. when a plant was installed at the Leeds Forge. Since that time the utilisation of water gas has advanced rapidly, and the manufacture of water gas, both blue and carburetted, is now an important auxiliary in the production of gas for town supply.