Robert Stirling[1] was born at Cloag Farm, a location in Scotland near the village of Methven, Perthshire.

[2] Though Robert, like his father and grandfather, had a natural inclination for engineering, he began attending Edinburgh University in 1805 at the age of fifteen to study divinity in hopes of becoming a minister.

[2][4] His brother James, who would play a major role in Stirling's future engineering endeavours, also attended Edinburgh at the age of 14.

In September 1816, the commissioner of the Duke of Portland granted Stirling the title of Minister as the second charge for the Laigh Kirk parish in Kilmarnock.

[2][6] Finally, in February 1824, Stirling was appointed as the minister of nearby Galston Parish Church where he continued his ministry until 1878.

[8] Amontons was followed in 1807 by George Cayley whose engine was of those in which the fire is enclosed, and fed by air pumped in beneath the grate in sufficient quantity to maintain combustion, while by far the largest portion of the air enters above the fire, to be heated and expanded; the whole, together with the products of combustion, then acts on the piston, and passes through the working cylinder; and the operation being one of simple mixture only, no heating surface of metal is required, the air to be heated being brought into immediate contact with the fire.

A two horse-power Stirling hot air engine, built in 1818 for pumping water at an Ayrshire quarry, continued to work for some time, until a careless attendant allowed the heater to become overheated.

This experiment proved to the inventor that, owing to the low working pressure obtainable, the engine could only be adapted to small powers for which there was at that time no demand.

This engine moved all the machinery at the Dundee Foundry Company's works for eight or ten months, and was previously found capable of raising 700,000 lbs one foot in a minute (approx.

Finding this power insufficient for their works, the Dundee Foundry Company erected the second engine, with a cylinder of 16 inches (approx.

This engine has now been in continual operation for upwards of two years, and has not only performed the work of the foundry in the most satisfactory manner, but has been tested (by a friction brake on a third mover) to the extent of lifting nearly 1,500,000 lbs (approx.

[23] In 1824 Stirling sought to improve the efficiency of the heat engine by attempting to separate the air present in the economizer.

The improvements added by Stirling included the addition of rods or plates in the passage through which hot air travelled to the cold section of the engine.

Additionally, Stirling added cupped leather collars around the piston rods to seal gaps and minimize the leakage of air from the engine.

The air vessel failure could be attributed to the metals being unable to withstand the high temperatures at which the engine was running.

[2] Though the Stirling engine is rarely used today, its seemingly perpetual motion capability continues to draw the interest of research institutions like Los Alamos National Laboratory and NASA.

[30] He is buried in Galston Cemetery where a new gravestone was erected in December 2014 by public subscription replacing the original stone which was in a ruined state.

[29] On 11 January 1840, Stirling was awarded the title Doctor of Divinity by the University of St. Andrews for his excellence in ministry.