Hornblower, Jonathan

SUBJECT AREA: Steam and internal combustion engines

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b. 1753 Cornwall (?), England

d. 1815 Penryn, Cornwall, England

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English mining engineer who patented an early form of compound steam engine.

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Jonathan came from a family with an engineering tradition: his grandfather Joseph had worked under Thomas Newcomen. Jonathan was the sixth child in a family of thirteen whose names all began with "J". In 1781 he was living at Penryn, Cornwall and described himself as a plumber, brazier and engineer. As early as 1776, when he wished to amuse himself by making a small st-eam engine, he wanted to make something new and wondered if the steam would perform more than one operation in an engine. This was the foundation for his compound engine. He worked on engines in Cornwall, and in 1778 was Engineer at the Ting Tang mine where he helped Boulton \& Watt erect one of their engines. He was granted a patent in 1781 and in that year tried a large-scale experiment by connecting together two engines at Wheal Maid. Very soon John Winwood, a partner in a firm of iron founders at Bristol, acquired a share in the patent, and in 1782 an engine was erected in a colliery at Radstock, Somerset. This was probably not very successful, but a second was erected in the same area. Hornblower claimed greater economy from his engines, but steam pressures at that time were not high enough to produce really efficient compound engines. Between 1790 and 1794 ten engines with his two-cylinder arrangement were erected in Cornwall, and this threatened Boulton \& Watt's near monopoly. At first the steam was condensed by a surface condenser in the bottom of the second, larger cylinder, but this did not prove very successful and later a water jet was used. Although Boulton \& Watt proceeded against the owners of these engines for infringement of their patent, they did not take Jonathan Hornblower to court. He tried a method of packing the piston rod by a steam gland in 1781 and his work as an engineer must have been quite successful, for he left a considerable fortune on his death.

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Bibliography

1781, British patent no. 1,298 (compound steam engine).

Further Reading

R.Jenkins, 1979–80, "Jonathan Hornblower and the compound engine", Transactions of the Newcomen Society 11.

J.Tann, 1979–80, "Mr Hornblower and his crew, steam engine pirates in the late 18th century", Transactions of the Newcomen Society 51.

J.Farey, 1827, A Treatise on the Steam Engine, Historical, Practical and Descriptive, reprinted 1971, Newton Abbot: David \& Charles (an almost contemporary account of the compound engine).

D.S.L.Cardwell, 1971, From Watt to Clausius. The Rise of Thermo dynamics in the Early Industrial Age, London: Heinemann.

H.W.Dickinson, 1938, A Short History of the Steam Engine, Cambridge University Press.

R.L.Hills, 1989, Power from Steam. A History of the Stationary Steam Engine, Cambridge University Press.

RLH