gasoven

from the top of the blast furnace are employed for Metall.: The oven in which the waste gases taken heating the air for the blast. tri but i on of gas. gas-pipe, s . A pipe for the conveyance and dis- Service-pipes are of various metals, wrought-iron tubing being now more com- mon than any other. The sections of distributing pipe have screw-socket couplings. A gas-pipe made of bra or copper is liable to have a deposit of a com- This explodes when heated. pound of acetyline C2H2 with copper formed in it. Iron- works : The puddling of iron by the use of gases instead of solid fuel. gas-purifier, s . An apparatus in which gas is purified of its sulphur compounds. The purification of gas by pa ing it through lime-water was intro- duced in 1807. The ordinary illuminating gas, after having been evolved in the retort, its tar eliminated in the condenser, and its ammonia extracted in the washer, is pa ed through the purifier, which re- sumption. moves the sulphur and renders the gas fit for con- gas-register, subst . An instrument by which the pre ure of gas is indicated and recorded. The season and the hour. An ordinary pre ure during rate of pre ure is not uniform, but varies with the the day is f of an inch; that is a pre ure which will raise a column of water in a tube to that height. At night the pre ure is increased accord- in winter is double that consumed in summer; more ing to the hour and the season; the quantity burnt at the latter hour than at 3 A. Μ. gas is burning at 9 P. M. than at 12 P. M.; and more gas-regulator, s. A device to equalize the flow of gas, notwithstanding varying pre ure in the building. on or shutting off gas to or from burners in a gas-retort, s. The chamber in which carbon a- ceo us matter is distilled to produce illuminating gas. Gas-retorts are made of iron or clay, and each forming the floor. These are set in a brick furnace, in shape is a segment of a cylinder, the flat side with their open ends presented outward ready for charging. the charge of coal into a retort, or removing the Gas-retort charger : An apparatus for introducing coke therefrom. [STEAM-STOKER.]