por Benjamin Thompson (1753-1814) was an American scientist and inventor famous for questioning Lavoisier’s caloric theory in the 19th century. This held that an invisible fluid released heat in bodies.
Thompson discovered that the increase in temperature was a consequence of friction. He came across this discovery when in a factory, drilling cannons, he observed that both the metal and the drill became hot during the procedure. Later, when he used water to cool the bit, the liquid boiled without the need for a fire.
This finding meant a great step for the development of thermodynamics. Although the process was very slow, there were intense debates and in the end it was proven that thermal energy is simply molecular kinetic energy.
His career as an inventor began in the American War of Independence. Even as an American he contributed to the British of his own free will and there he became a major in a militia company.
In the war he designed a lifebelt so that workhorses could cross the river without drowning and a carriage to transport cannons. He also delved into the investigation of human nutrition and made great social contributions.
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Biography
early years
He was born on March 26, 1753 in Woburn, Massachusetts. He attended a modest school, but sometimes he escaped to Harvard College -a more prestigious institution- to listen to the lectures of Professor John Winthrop (political leader and first governor of Massachusetts).
As a young man he worked as a clerk in a store. But the owner of the place complained to Thompson’s mother because he gave more importance to reading science books and making machines than to serving customers.
When he was 13 years old, he became an apprentice to John Appleton, a lawyer and diplomat who was the first US chargé d’affaires in Bolivia. This approach allowed Thompson to have contact with people of good education.
He adopted some of the habits of those around him, there his interest in science grew more. However, he went from one job to another without much success.
Role in the War of Independence
Benjamin Thompson’s life took a significant turn in the year 1772 when he met a widow and heiress with whom he fell in love. He married Sarah Rolfe, she had great influence with the governor of Portsmouth, New Hampshire and thanks to this he was named one of the commanders of the Militia.
When the American Revolutionary War began, Benjamin Thompson owned some land in New England and was against the uprising, so he activated troops to fight the royalists.
The popular party became his enemy because they considered him a traitor and in revenge a mob attacked his wife. Following these events, he fled to the British lines and became an adviser to General Gage and Lord George Germain.
In 1785 he went to Bavaria, where he spent eleven years working for the army and in 1791 received the title of Count of the Holy Roman Empire, thus adopting the name «Rumford».
Your personality
Thanks to some notes found in his diary, today Benjamin Thompson can be described as a very organized man. He put everything in writing and stuck to a schedule, every moment of the day he was planned in advance.
In his notes it is found that he established Monday and Tuesday for the study of anatomy, Wednesdays he dedicated to the physics institutes, Thursdays to surgery, Fridays to chemistry with materia medica, and Saturdays to physics. His avidity for study allowed him to rub shoulders with people from different professions.
He also left his activities marked by hour, he even wrote down the time to get up, wash his hands and have breakfast.
Earl Rumford’s death was sudden in the month of August 1814. He left a will that his assets were given as an inheritance to Harvard College. Today his tomb is in a cemetery in Auteuil (France) and Harvard University is in charge of its maintenance.
Contributions and discoveries by Benjamin Thompson
Benjamin Thompson is known to have carried out a large number of experiments throughout his life. With his boyhood friend Loammi Baldwin (years later he became a prominent American politician and soldier) he created a scientific society to exchange problems and puzzles for several years.
He devoted a great deal of effort to the construction of a continuous motion machine, an electrical instrument similar to the Van de Graaf generator. He also carried out various studies on the force of gunpowder explosions and thanks to these he was elected to be part of the Royal Society.
– Contributions
The intensity with which he worked to prove his theories and create tools to improve people’s lives paid off. These are some of his documented contributions:
Invisible Ink
On May 6, 1775, a letter from him crossed military lines in a context in which correspondence was being inspected. Benjamin Thompson sent a sheet of paper with important information from the war, but it only read about five lines.
The uniformed officers did not take into account that it was a very large sheet for what it said there. On the rest of the sheet was a hidden message written in invisible ink obtained with gallotanic acid.
Vacuum food preparation
In 1799 Benjamin Thompson first mentioned the sous-vide method, which is nothing more than the preparation of food under vacuum. His first experiment was done with a pork shoulder.
rumford soup
It was a food made for the soldiers with the minimum cost, but with an excellent nutritional capacity. It was prepared with potatoes, peas and cereals. Although it was designed for soldiers, it had a strong penetration in Europe and was served in soup kitchens and charity places.
– Discoveries
Many of his theories were incorrect, despite the fact that he used all the variables of the time and had great dedication to research. However, many of them were easily at an impasse. In any case, he did achieve important inventions that still have functionality today.
convection currents
It was one of his most important discoveries. It is a way of transporting heat between two areas with different temperatures. For this there must be water or some other fluid for the evaporation process to take place.
When making this revelation he made numerous experiments with all kinds of substances and, after studying each one of the results, he published his theory that said that «every substance that tends to impede the movement of a fluid, whether it is a liquid or a gas, increases the insulating properties of the material.
chimney improvements
In London the chimneys had a great acceptance and it was Benjamin Thompson who made a significant improvement to this invention. The new design added bricks to create a column of angled walls to keep all the smoke flowing upwards and leaving no part of it in the room. In addition, it increased the efficiency of the fire by controlling the rate of fuel consumption.
industrial ovens
When Thompson improved the kilns used for the production of lime, production began immediately throughout Europe. The correction was summarized to separate the burning of the fuel from the limestone, in this way, the ashes were not contaminated by the fire.
Thermal underwear
This American is credited with inventing warm underwear. Thompson studied the thermal conductivity of fabrics for years in an effort to improve military clothing.
light and photometry
From his discoveries with heat he went on to work on photometry or light measurement. For this he built a photometer and used his own unit of light intensity.
perfected lamps
After working on photometry, Thompson wanted to put his discoveries into practice. He took some lamps invented by a Swiss man by the name of Ami Argand and perfected some of the processes to improve luminosity and reduce the use of oil.
filter coffee maker
Count Rumford liked the comfort, the good life and considered that the consumption of alcohol distorted that concept. Therefore, he looked for something that could replace it and concluded that only coffee was capable of doing so.
However, it had an obstacle. How to prepare it in a simple way? That was how he discovered that it had to be done at a constant temperature and in a closed container so that it also retained all its flavor.
He found the solution to create what is now called a filter coffee maker.
Publications
Some of the papers on his investigations were published, many of them taken directly from the quotes he made in his diary. These are the most famous texts of the count:
– Heat and its application to the various purposes of life.
– The combustion of flammable bodies.
– Fire management and fuel economy.
– Principle of heat imparted by clothing.
Acknowledgments
– The lunar crater Rumford bears his name in memory of this inventor. It is one of the hidden faces of the moon.
– At Harvard University, the chair of natural philosophy was named in his honor.
– Since 1800, the Royal Society has awarded the Rumford Medal each year, an award for outstanding scientific research related to the thermal or optimal properties of matter.
References
Sanbornc C. Brow (1965) Count Rumford.
E. Alexander Powell (1956) The Remarkable American Count.
Annals Royal National Academy of Medicine (2006) Volume CXXIII.
Frederick Bueche (1988) Physical sciences.
Francis Weston Sears, Gerhard L. Salinger (1980) Kinetic thermodynamics theory and statistical thermodynamics.