What scientific principle motivated Thomas Savery's 1698 'fire engine' patent for raising mine water?

Answer

Creating a vacuum by allowing condensed steam to collapse within a vessel

Thomas Savery's design, patented in 1698, operated entirely on the principle of vacuum creation rather than using steam pressure directly to push water out. In his mechanism, steam would first fill a closed vessel. Subsequently, cold water would be introduced, causing the steam inside to rapidly condense back into a liquid state. This condensation dramatically reduced the pressure inside the vessel, creating a partial vacuum. Consequently, the superior atmospheric pressure acting on the surface of the external water source would force the water up the suction pipe and into this void within the vessel. This process required only hand-operated taps to manage the cycles.

What scientific principle motivated Thomas Savery's 1698 'fire engine' patent for raising mine water?
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