Scottish clergyman, best known as the inventor of the Stirling engine, a type of external-combustion engine. He also invented optical devices and other instruments.

Stirling's first patent was granted in 1816, and his engines were manufactured from 1818 to 1922, during which time they were used to pump water on farms and to generate electricity. Later attempts to develop the Stirling engine for commercial use proved largely unsuccessful, though its potential for quiet operation, multiple fuel sources, high efficiency, low pollution, and high power density continues to hold considerable attraction for researchers.