The History of the Rumford Fireplace and its Inventor

The name Rumford does not only apply to the style and shape of a particular fireplace. It is the name of its inventor as well. Count Rumford led a very intriguing life and his history is well-placed in both North America and Europe. He was a scientist, inventor and adventurer. His main investigations led him to study the effects of heat and how it is transmitted.

Rumford applied his knowledge of heat to the improvement of fireplaces. He made them smaller and shallower with widely angled covings to reflect more heat. He also streamlined the throat to eliminate turbulence and carry away the smoke with little loss of heated room air.

Count Rumford created a sensation in London when he introduced the idea of restricting the chimney opening to increase the updraught. He and his workers changed 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. It effectively produced a streamlined air flow, so all the smoke would go up into the chimney rather than lingering and often choking the residents. Many fashionable London houses were modified to his instructions, and became smoke-free. He became a celebrity when news of his success became widespread.

Rumford wrote two papers detailing his improvements on fireplaces in 1796 and 1798. He was well-known and his papers were widely read in his lifetime and almost immediately in the 1790’s his “Rumford fireplace” became state-of-the-art worldwide.

Benjamin Thompson: Inventor, Spy and Count of the Holy Roman Empire

Born as Benjamin Thompson, Count Rumford was born in rural Woburn, Massachusetts, on March 26, 1753; his birthplace is preserved to this day as a museum. He was educated mainly at the village school, although he sometimes walked to Cambridge with the older Loammi Baldwin to attend lectures by Professor John Winthrop at Harvard College. At the age of thirteen, he was apprenticed to John Appleton, a merchant from 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 science. While recuperating from an injury in Woburn in 1769, 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 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; moved to Portsmouth, New Hampshire; and through his wife's influence with the governor, was appointed a major in a New Hampshire Militia.

When the American Revolution began, Thompson was a man of property and standing in New England and was opposed to the rebels. 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, forever. Thompson was welcomed by the British, to whom he gave valuable information about the American forces and became an advisor to both General Gage and Lord Germain.

While working with the British armies in America, he conducted experiments concerning the force of gunpowder, the results of which were widely acclaimed when published, in 1781, in the Philosophical Transactions of the Royal Society. Thus, when he moved to London at the conclusion of the war, he already had a reputation as a scientist.

Bavarian maturity:

In 1785, he moved to Bavaria where he became an aide-de-camp to the Prince-elector Karl Theodor. He spent eleven years in Bavaria reorganizing the army and establishing workhouses for the poor. During his work, he also invented the Rumford Soup, a nutritious soup for the poor, and established the cultivation of the potato in Bavaria. He invented the wax candle to replace the smoky tallow or beef fat ones. He also founded the Englischer Garten in Munich which still remains today and is known as one of the largest urban public parks in the world. In 1792, for all these contributions, the elector of Bavaria made Benjamin Thompson a count of the Holy Roman Empire. For his title, Thompson chose Rumford, the earlier name of Concord where his fortunes had changed so dramatically.

Experiments on heat:

His experiments on gunnery and explosives led to an interest in heat. He devised a method for measuring the specific heats of solids but was disappointed that Johan Wilcke had priority.

Thompson next investigated the insulating properties of various materials including fur, wool and feathers. He correctly appreciated that the insulating properties of these natural materials arise from the fact that they inhibit the convection of air. He then made the somewhat reckless, and incorrect, inference that air and, in fact, all gases were perfect non-conductors of heat. He further saw this as evidence of the argument from design, contending that divine providence had arranged for fur on animals in such a way as to guarantee their comfort.

In 1797, he extended his claim about non-conductivity to liquids. The idea raised considerable objections from the scientific establishment, John Dalton and John Leslie making particularly forthright attacks.The instrumentation needed to verify Thompson's claim far exceeded anything available in terms of accuracy and precision. Again, he seems to have been influenced by his theological beliefs and it is likely that he wished to grant water a privileged and providential status in the regulation of human life.

Mechanical equivalent of heat:

However, his most important scientific work took place in Munich, and centered on the nature of heat which he contended in An Experimental Enquiry Concerning the Source of Heat which is Excited by Friction (1798), was not the caloric of then-current scientific thinking but a form of motion. Rumford had observed the frictional heat generated by boring cannon at the arsenal in Munich. Rumford immersed a cannon barrel in water and arranged for a specially blunted 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. Rumford confirmed that no physical change taken place in the material of the cannon by comparing the specific heats of the material machined away and that remaining were the same.

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

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


He was an active inventor, developing improvements for chimneys and fireplaces and inventing the double boiler, a kitchen range, and a drip coffeepot.

To his credit, he deliberately did NOT patent any of his inventions; rather, he publicized them for the common good. He was a (self-made) aristocrat, extremely autocratic and quite unable to get along with people as individuals. At the same time, he was also very public-spirited, with a real interest in helping the poor.

Later Life:

After 1799, he divided his time between France and England. With Sir Joseph Banks, he established the Royal Institution of Great Britain in 1799.

Thompson settled in Paris and continued his scientific work until his death on August 21, 1814. Thompson is buried in the small cemetery of Auteuil in Paris.

Direct quotes from the Count himself:

“To all those who take pleasure in doing good to mankind by promoting useful knowledge, and facilitating the means of procuring the comforts and conveniences of life, these investigations cannot but be very interesting”

Early Environmentalism:

“The enormous waste of fuel in London may be estimated by the vast, dark cloud which continually hangs over this great metropolis and frequently overshadows the whole country, far and wide. For this dense cloud is certainly composed almost entirely of unconsumed coal. I never view from a distance as I come into town this black cloud which hangs over London without wishing to be able to compute the enormous number of cauldrons of coal of which it is composed. For, could this be ascertained, I am persuaded, so striking a fact would awaken the curiosity and excite the astonishment of all ranks of the inhabitants and perhaps turn their minds to an object of economy to which they have hitherto paid little attention”

Works Cited:

Contributors, Wikipedia. Benjamin Thompson. Wikipedia, The Free Encyclopedia. 16 June 2008, as per the GNU Free Documentation License .

Rowlinson, Hugh. The Contribution of Count Rumford to Domestic Life in Jane Austen’s Time. Winter 2002. 16 June 2008

King, Allen L. Count Rumford, Sanborn Brown, and the Rumford Mosaic. 19 June 2008