This article is about the Scottish engineer and inventor. For Ronald Reagan's Secretary of the Interior, see James G. Watt.

James Watt (January 19, 1736–August 19, 1819) was a Scottish mathematician and engineer whose improvements to the steam engine were a key stage in the Industrial Revolution.

He was born in Greenock, Scotland, and lived and worked in Birmingham, England. He was a key member of the Lunar Society. Many of his papers are in Birmingham Central Library.

Timeline

• 1736: Born in Greenock, Scotland.
• 1754: Learnt the trade of mathematical-instrument making in London before returning to Glasgow
• 1763: Repaired a Newcomen steam engine, which started him thinking about ways to improve the engine.
• 1765: While wandering through the Glasgow Green's "Golf Course", comes upon the idea of a separate condensing chamber for the steam engine.
• 1767: Surveyor of Forth and Clyde canal.
• 1769: Patented separate condensing chamber for steam engine.
• 1774: Started a business in Soho, near Birmingham, with Matthew Boulton to manufacture his improved Watt steam engine.
• 1781: Converted reciprocal engine motion to rotary motion.
• 1782: Invented double-acting engine.
• 1784: Patented a steam locomotive.
• 1788: Adapted centrifugal governor for use on steam engine.

Engineering Achievements

Watt adopted the centrifugal governor to regulate the speed of a steam engine. (This was already in use for governing wind and watermills.) He invented the parallel motion linkage to convert circular motion to an approximate straight line motion (of which he was most proud) and the steam indicator to measure steam pressure in the cylinder throughout the working cycle of the engine, so showing its efficiency.

Watt greatly helped the development of the embryonic steam engine into a viable and economic means of power generation. He realised that the Newcomen steam engine was wasting nearly three quarters of the steam energy in heating the piston and chamber. Watt developed a separate condenser chamber which significantly increased the efficiency. Further refinements (insulation of the steam cylinder, the double-acting engine, a counter, an indicator, and a throttle valve) made the steam engine his life's work.

Watt was opposed to the use of high pressure steam, and is held by some to have held back the technical development of the steam engine by other engineers, until his patents expired in 1800. With his partner Matthew Boulton he battled against rival engineers such as Jonathan Hornblower who tried to develop engines which did not fall foul of his 'catch-all' patents. Boulton proved an excellent businessman, and both men eventually made fortunes.

He introduced a unit called the horsepower to compare the power output of steam engines, his version of the unit being equivalent to 550 foot-pounds per second (about 745.7 watts).

Watt also invented several other things, not least a copying device for letters.

Legacy

James Watt's model of the steam engine converted a machine of limited use to one of efficiency and many applications. It was the foremost energy source in the emerging Industrial Revolution, and greatly multiplied its productive capacity. (Without it, humans might have continued to provide power.) It was also essential in later transportation advancements, such as the steamboat and locomotive.

Remembrance

The SI unit of power, the watt, is named after him. So is, at least in part, Edinburgh's Heriot-Watt University.

He is also remembered by the Moonstones, two individual statues, and a statue of him, Boulton and Murdoch by William Bloye, and a school named in his honour, all in Birmingham.

There are 4 colleges named after him in Scotland, James Watt College in Kilwinning (North Ayrshire Campus) and Greenock (2 in Greenock, Finnart Campus and Waterfront Campus) and a campus in Largs.

Matthew Boulton's home, Soho House, is now a museum, commemorating the work of both men.

There are over 50 roads or streets named after him, in the UK.

See also

• Steam engine

and his predecessors:

• Hero of Alexandria
• Thomas Savery
• Thomas Newcomen
• Joseph Black
• Boulton, Watt and Murdoch, a statue of same

Bibliography

Rev. Dr. Richard L, Hills, James Watt, Vol 1, His time in Scotland, 1736-1774 (2002), 480pp, many illus., Landmark Publishing Ltd, (ISBN 1-84306-045-0) [ The second volume covering his time in England until his death in 1819 is due for publication in 2005.]