Benjamin Thompson (Edited from Wikipedia)

SUMMARY

Sir Benjamin Thompson, Count Rumford, ( March 26, 1753 – August 21, 1814) was an American-born British physicist and inventor whose challenges to the established theory of were part of the 19th century revolution in . He served as lieutenant-colonel of the King's American Dragoons, part of the British Loyalist forces, during the American Revolutionary War.

After the end of the war he moved to , where his administrative talents were recognized when he was appointed a full Colonel, and in 1784 he received a knighthood from King George III. A prolific designer, Thompson also drew designs for warships. He later moved to Bavaria, in modern Germany, and entered government service there. He was appointed Bavarian Army Minister and re-organized the army, and, in 1791, was made a Count of the Holy Roman Empire.

HISTORY

Thompson was born in rural Woburn, , on March 26, 1753; his birthplace is preserved as a museum. He was educated mainly at the village school, although he sometimes walked to Cambridge near ten miles distant with his older friend, . They attended lectures by Professor of . At the age of 13 he was apprenticed to a merchant of nearby Salem. Thompson excelled at his trade, and coming in contact with refined and well educated people for the first time, he adopted many of their characteristics including an interest in .

While healing in Woburn in 1769 from an injury, Thompson conducted experiments concerning the nature of heat and began to correspond with Loammi Baldwin and others about them. Later that year he worked for a few months for a Boston shopkeeper and then apprenticed himself briefly, and unsuccessfully, to a doctor in Woburn.

Thompson's prospects for marriage were dim in 1772 but in that year they changed abruptly. He met, charmed and married a rich and well-connected heiress named Sarah Rolfe. Her father was a minister, and her late husband left her property at Concord, New Hampshire, then called Rumford. They moved to Portsmouth, New Hampshire,

1 and through his wife's influence with the governor, he was appointed a major in the New Hampshire Militia.

When the American Revolutionary War began, Thompson was a man of property and standing in New England and was opposed to the uprising. He was active in recruiting loyalists to fight the rebels. This earned him the enmity of the popular party, and a mob attacked Thompson's house. He fled to the British lines, abandoning his wife, as it turned out, permanently. Thompson was welcomed by the British because he gave them valuable information about the American forces.

While working with the British armies in America he conducted experiments to measure the force of gunpowder, the results of which were widely acclaimed when published in 1781 in the Philosophical Transactions of the Royal Society . On the strength of this he arrived in London at the end of the war with a reputation as a scientist.

Experiments With Heat

His experiments on gunnery and explosives led to an interest in heat. He devised a method for measuring the specific heat of a solid substance (meaning the amount of heat required to change a substance’s ) but was disappointed when Johan Wilcke published his parallel discovery first.

Thompson next investigated the insulating properties of various materials, including fur, wool and feathers.

He is considered as the founder of the sous-vide food preparation method due to his experiment with a mutton shoulder. He described this method in one of his essays.

However, Thompson’s most important scientific took place in , and centered on the nature of heat, which he contended in An Experimental Enquiry Concerning the Source of the Heat which is Excited by Friction (1798) was not the caloric of then- current scientific thinking but a form of motion.

Thompson had observed the frictional heat (rubbing the metals together) generated by boring cannon at the arsenal in Munich. Thompson immersed a cannon barrel in water and arranged for a special boring tool. He showed that the water could be boiled within roughly two and a half hours and that the supply of frictional heat was seemingly inexhaustible. Thompson confirmed that no physical change had taken place in the material of the cannon by comparing the specific of the material machined away and that remaining.

2 Thompson argued that the seemingly indefinite generation of heat was incompatible with the . He contended that the only thing communicated to the barrel was motion.

Thompson made no attempt to further quantify the heat generated or to measure the mechanical equivalent of heat. Though this work met with a hostile reception, it was subsequently important in establishing the laws of conservation of later in the 19th century.

INVENTIONS

Thompson was an active and prolific inventor, developing improvements for chimneys, and industrial furnaces, as well as inventing the double boiler, a kitchen range, and a drip coffeepot. He invented a percolating coffee pot following his pioneering work with the Bavarian Army, where he improved the diet of the soldiers as well as their clothes.

The Rumford created a sensation in London when he introduced the idea of restricting the chimney opening to increase the updraft, which was a much more efficient way to heat a room than earlier fireplaces.

He and his workers modified fireplaces by inserting bricks into the hearth to make the side walls angled, and added a choke to the chimney to increase the speed of air going up the flue (the opening up top). The effect was to produce a streamlined air flow, so all the smoke would go up into the chimney rather than lingering, entering the room, and often choking the residents. It also had the effect of increasing the efficiency of the fire, and gave extra control of the rate of combustion of the fuel, whether wood or coal. Many fashionable London houses were modified to his instructions, and became smoke-free.

LATER LIFE

After 1799, he divided his time between and England. With Sir , he established the of in 1799. The pair chose Sir as the first lecturer. The institution flourished and became world famous as a result of Davy's pioneering research. His assistant, established the Institution as a premier research laboratory, and also justly famous for its series of public lectures popularizing science. That tradition continues to the present,

3 and the Royal Institution Christmas lectures attract large audiences through their TV broadcasts.

In 1804, he married Marie-Anne Lavoisier, the widow of the great French chemist , his American wife—the one he abandoned in America upon the outbreak of the American Revolution—having died since his emigration.

Thompson separated from his second wife after 3 years, but Thompson settled in and continued his scientific work until his death on August 21, 1814. Thompson is buried in the small cemetery of Auteuil in Paris, just across from Adrien-Marie Legendre. Upon his death, his daughter from his first marriage, Sarah Thompson, inherited his title as Countess Rumford.

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