Watt Steam Engine

Heat engine · 1776 · Rankine cycle

Year: 1776
Kind: Heat engine
Materials: Cast iron, wrought iron, brass; the cylinder bored on Wilkinson's cannon-boring machine, the first machine tool accurate enough for the job.
Efficiency: 3–5 % — three to four times Newcomen's, which is why it displaced him.
Used In: Mills, mines, breweries — anything that had turned on water or horses.
Power Density: Low, but enough to turn a mill.
Cycle: Rankine

How It Works

Watt's insight was to condense the steam in a separate vessel kept cold, so the cylinder could stay hot; then he closed the top of the cylinder and used steam pressure on both sides, added a crank to make rotary motion, and a centrifugal governor to hold speed. That combination is the machine that ran the Industrial Revolution.

Inventors

James Watt

Equations

Second Law of Thermodynamics First Law of Thermodynamics Ideal Gas Law Thermal Efficiency Power Torque

Elements

Copper Iron

Referenced by

element

Copper Iron

equation

First Law of Thermodynamics Ideal Gas Law Power Second Law of Thermodynamics Thermal Efficiency Torque

researcher

James Watt

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From the Machines database in Notion, last edited 2026-08-18. This page is the row, rendered by the build; nothing on it is written by hand.