What is the exhaust steam from and engine, driving a column of air out of a boiler chimney, and thus creating an intense draught through the fire; also, any draught produced by the blast called?

blast — The exhaust steam from and engine, driving a column of air out of a boiler chimney, and thus creating an intense draught through the fire; also, any draught produced by the blast. (Webster's 1913.)

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