Reverend Dr Robert Stirling
25 October 1790|
|Died||6 June 1878
Galston, East Ayrshire
|Citizenship||United Kingdom of Great Britain and Ireland|
|Children||Patrick Stirling b.1820
Jane Stirling b.1821
William Stirling b.1822
Robert Stirling b.1824
David Stirling b.1828
James Stirling b.1835
Agnes Stirling b.1838
|Parents||Patrick Stirling Agnes Stirling|
|Significant projects||Stirling engine|
The Reverend Dr Robert Stirling (25 October 1790 – 6 June 1878) was a Scottish clergyman, and inventor of the Stirling engine. Stirling was born at Cloag Farm near Methven, Perthshire, the third of eight children. He inherited his father's interest in engineering, but studied divinity at the University of Edinburgh and the University of Glasgow becoming a minister of the Church of Scotland as second charge of the Laigh Kirk of Kilmarnock in 1816.
On 10 Jul 1819, Stirling married Jean Rankin. They had seven children:
- Patrick Stirling, born 29 Jun 1820, became a locomotive engineer
- Jane Stirling, born 25 Sep 1821, fed ideas to her brothers
- William Stirling born 14 Nov 1822, became a civil engineer and railway engineer in South America
- Robert Stirling, born 16 Dec 1824, became a railway engineer in Peru.
- David Stirling, born 12 Oct 1828, became the Minister of Craigie, Ayrshire
- James Stirling, born 02 Oct 1835, became a locomotive engineer
- Agnes Stirling, born 22 Jul 1838, became an artist
Engineering and science 
Hot air engine 
He invented what he called the Heat Economiser (now generally known as the regenerator), a device for improving the thermal/fuel efficiency of a variety of industrial processes, obtaining a patent for the economiser and an engine incorporating it in 1816. In 1818 he built the first practical version of his engine, used to pump water from a quarry.
Optical instruments 
While in Kilmarnock, he collaborated with another inventor, Thomas Morton, who provided workshop facilities for Stirling's research. Both men were interested in astronomy, and having learnt from Morton how to grind lenses, Stirling invented several optical instruments.
Robert, together with his brother James, an engineer, took out several further patents for improvements to the air engine and in the 1840s James built a large air engine driving all the machinery at his Dundee Foundry Company.
Bessemer process 
In a letter of 1876, Robert Stirling acknowledged the importance of Henry Bessemer's new invention – the Bessemer process for the manufacture of steel – expressing a hope that the new steel would improve the performance of air engines.
Stirling died in Galston, East Ayrshire on 6th June 1878.