Treasure's description

Engine for raising water by fire

Engine for raising water by fire

The illustration is taken from the John Harris’s ‘Lexicon technicum’, the first dictionary of technical terms. This copy is from the second edition, published between 1708 and 1710, and shows Thomas Savery’s patented pumping engine. The engine worked by alternating the supply of steam between the two vessels labelled P. Once one of these vessels had been filled with steam, it was subjected to a douche of cold water, condensing the steam inside and sucking water up pipe T into the vessel. Reactivating the supply of steam to the vessel caused the water to be driven up pipe S, at the same time that the steam in the other vessel was being condensed, drawing a further draught of water from below. One way valves (R) were crucial to the operation of the engine.