Low-press′ure En′gine.
（Steam-engine.) In [1359] England, one in which a condenser is used, and whose safety-valve is loaded at from four to six pounds to the square inch. — Lardner. The terms high and low pressure steam were formerly held to mean saturated steam at a pressure above or below that which will sustain a column of thirty inches of mercury; the boiling heat of water, 212° of Fahrenheit. The term low pressure signifies in this country a pressure of not over fifty pounds to the square inch.
