- Ben Marsden
Stirling, Robert (1790–1878), Church of Scotland minister and inventor of a hot-air engine, was born on 25 October 1790 in the parish of Methven, Perthshire, the son of Peter Stirling, farmer at Cloag. He studied at the University of Edinburgh (1805–6) and was licensed to preach by the presbytery of Dumbarton in July 1815. He was presented by the duke and duchess of Portland to the second charge at the Laigh Kirk, Kilmarnock, the next year, and ordained in September 1816. On 10 July 1819 he married Jane (d. 1892), eldest daughter of William Rankine, postmaster and wine merchant of Galston. They had two daughters (Jane and Agnes) and five sons, four of whom were innovative locomotive and railway engineers in Britain (Patrick Stirling and his brother James) and South America (William and Robert). Another son, David, entered the church.
After seven years at Kilmarnock, Stirling was presented by Portland to the neighbouring parish of Galston and admitted in February 1824. As a parochial pastor he delivered well wrought sermons with a rapidity which did not guarantee attention, worked to establish the free school in Kilmarnock, ministered to his ailing congregation during the cholera epidemic of 1848–9, and promoted the enlargement of the psalmody of the Church of Scotland. His excellence in classical scholarship, and as a student of science, earned him the honorary degree of DD from St Andrews (11 January 1840), even though his only published work was a dutiful 1837 sketch of the political economy (and moral decline) of his parish for The New Statistical Account (1845). His career faltered during the acrimonious prelude to the Disruption (1843). On 30 May 1842 Stirling was severely censured by the general assembly for supporting the ministers of Strathbogie who had been suspended when church and legislature came into conflict over patronage in clerical appointments. Stirling was suspended from his judicial functions in the presbytery and other church judicatories until 1 March 1843. He survived to become father of the church (1876) but thereafter his health failed and he died at the manse on 6 June 1878. He was buried in Galston churchyard four days later.
Michael Stirling, Stirling's grandfather, was the inventor of a threshing machine. Robert Stirling himself was hardly 'one of your lavender glove people' (Kilmarnock Standard, 6 July 1878). He studied practical mechanics as a boy. At Galston he maintained a workshop adjoining the manse where he dextrously constructed scientific instruments. In November 1816, shortly after his ordination, he patented an engine which produced motive power from heated air: this machine's economizer (a heat exchanger, or regenerator) aimed to reuse caloric (or heat) otherwise wasted. Stirling foresaw fuel efficiencies significantly higher than those of contemporary steam engines, and he speculated on the use of the economizer principle to cheapen iron smelting. In February 1827 and October 1840 he patented improved hot-air engines with his brother James Stirling (1800–1876), a civil engineer. An engine of 45 hp overcame many, but not all, practical difficulties, working sporadically during the early 1840s to drive the machinery at James's Dundee foundry. Until the mid-1850s Stirling engines attracted considerable attention and controversy among mechanical engineers looking for a substitute for steam and natural philosophers reforming the science of heat.
- D. W. Loveridge, ‘Robert Stirling: preacher and inventor’, Transactions [Newcomen Society], 50 (1978–9), 1–10
- Fasti Scot., new edn, 3.40, 108
- Kilmarnock Standard (8 June 1878)
- Kilmarnock Standard (15 June 1878)
- Kilmarnock Standard (22 June 1878)
- Kilmarnock Standard (6 July 1878)
- The Scotsman (8 June 1878)
- J. M. A. Lenihan and J. R. McKay, ‘Dr Stirling and his engine’, College Courant: Journal of the Glasgow University Graduates Association, 26/52 (1974), 22–5 [Whitsun 1974]
- R. Stirling, ‘Parish of Galston’, The new statistical account of Scotland, 5 (1845)
- photograph, repro. in Lenihan and McKay, ‘Dr. Stirling and his engine’, 22
Wealth at Death
£6903 2s. 6d.: confirmation, 20 Aug 1878, CCI
£1608 6s. 8d.: additional estate, 17 July 1891, CCI