British-American man of science, philanthropist and administrator, was born at Woburn, in Massachusetts, on the 26th of March 1753. The Thompson family had been settled in New England since the middle of the previous century, and belonged to the class of moderately wealthy farmers. His father died while he was very young, and his mother speedily married a second time. But he seems to have been well cared for, and he was at the age of fourteen sufficiently advanced “in algebra, geometry, astronomy, and even the higher mathematics,” to calculate a solar eclipse within four seconds of accuracy. In 1766 he was apprenticed to a storekeeper at Salem, in New England, and while in that employment occupied himself in chemical and mechanical experiments, as well as in engraving, in which he attained to some proficiency.
The outbreak of the American War put a stop to the trade of his master, and he thereupon left Salem and went to Boston, where he engaged himself as assistant in another store. He was at that period between seventeen and eighteen years old, and at nineteen, he says, “I married, or rather I was married.” His wife was the widow of Colonel Benjamin Rolfe, and the daughter of Timothy Walker, “a highly respectable minister, and one of the first settlers at Rumford,” now called Concord, in New Hampshire. His wife was possessed of considerable property, and was his senior by fourteen years.
This marriage was the foundation of his success. Soon after it he became acquainted with Governor Wentworth of New Hampshire, who conferred on him the majority of a local regiment of militia. He speedily became the object of distrust among the friends of the American cause, and it was considered prudent that he should seek an early opportunity of leaving the country. On the evacuation of Boston by the royal troops, therefore, in 1776, he was selected by Governor Wentworth to carry despatches to England. On his arrival in London Lord George Germain, secretary of state, appointed him to a clerkship in his office. Within a few months he was advanced to the post of secretary of the province of Georgia, and in about four years he was made under-secretary of state.
His official duties, however, did not interfere with the prosecution of scientific pursuits, and in 1779 he was elected a fellow of the Royal Society. Among the subjects to which he especially directed his attention were the explosive force of gunpowder, the construction of firearms, and a system of signalling at sea. In connexion with the last, he made a cruise in the Channel fleet, on board the “Victory,” as a volunteer under the command of Admiral Sir Charles Hardy. On the resignation of Lord North's administration, of which Lord George Germain was one of the least popular members, he left the civil service, and was nominated to a cavalry command in the revolted provinces of America. But the War of Independence was practically at an end, and in 1783 he finally quitted active service, with the rank and half-pay of a lieutenant-colonel.
He now formed the design of joining the Austrian army, for the purpose of campaigning against the Turks, and so crossed over from Dover to Calais with Gibbon, who, writing to his friend Lord Sheffield, calls his fellow-passenger “Mr Secretary-Colonel-Admiral-Philosopher Thompson.” At Strassburg he was introduced to Prince Maximilian, afterwards elector of Bavaria, and was by him invited to enter the civil and military service of that state. Having obtained the leave of the British government to accept the prince's offer, he received the honour of knighthood from George III., and during eleven years he remained at Munich as minister of war, minister of police, and grand chamberlain to the elector. His political and courtly employments, however, did not absorb all his time, and he contributed during his stay in Bavaria a number of papers to the Philosophical Transactions. But that he was sufficiently alert as the principal adviser of the elector the results of his labours in that capacity amply prove.
He reorganized the Bavarian army; he immensely improved the condition of the industrial classes throughout the country by providing them with work and instructing them in the practice of domestic economy; and he did much to suppress mendicity. The multitude of beggars in Bavaria had long been a public nuisance and danger. In one day he caused no fewer than 2600 of these outcasts and depredators in Munich and its suburbs alone to be arrested by military patrols, and transferred by them to an industrial establishment which he had prepared for their reception. In this institution they were both housed and fed, and they not only supported themselves by their labours but earned a surplus for the benefit of the electoral revenues. The principle on which their treatment proceeded is stated by him in the following memorable words: “To make vicious and abandoned people happy,” he says, “it has generally been supposed necessary first to make them virtuous. But why not reverse this order? Why not make them first happy, and then virtuous?”In 1791 he was created a count of the Holy Roman Empire, and chose his title of Rumford from the name as it then was of the American township to which his wife's family belonged. In 1795 he visited England, one incident of his journey being the loss of all his private papers, including the materials for an autobiography, which were contained in a box stolen from off his postchaise in St Paul's Churchyard. During his residence in London he applied himself to the discovery of methods for curing smoky chimneys and the contrivance of improvements in the construction of fireplaces. But he was quickly recalled to Bavaria, Munich being threatened at once by an Austrian and a French army. The elector fled from his capital, and it was entirely owing to Rumford that a hostile occupation of the city was prevented. It was now proposed that he should be accredited as Bavarian ambassador in London; but the circumstance that he was a British subject presented an insurmountable obstacle. He, however, again came to England, and remained there in a private station for several years.In 1798 he presented to the Royal Society his “Enquiry concerning the Source of Heat which is excited by Friction,” in which he combated the current view that heat was a material substance, and regarded it as a mode of motion. In 1799 he, in conjunction with Sir Joseph Banks, projected the establishment of the Royal Institution. It received its charter of incorporation from George III. in 1800, and Rumford himself selected Sir Humphry Davy as scientific lecturer there. Until 1804 he lived at the Royal Institution in Albemarle Street, London, or at a house which he rented at Brompton, and he then established himself in Paris, marrying (his first wife having died in 1792) as his second wife the wealthy widow of Lavoisier, the celebrated chemist. With this lady he led an extremely uncomfortable life, till at last they agreed to separate. He took up his residence at Auteuil, where he died suddenly on the 21st of August 1814, in the sixty-second year of his age.
Encyclopedia Britannica, 1911