The Human Side of Science: Edison and Tesla, Watson and Crick, and Other Personal Stories behind Science's Big Ideas (2016)

Chapter 5: Antoine Lavoisier and Benjamin Thompson (Count Rumford) Have Rival Theories of Heat

If you can't stand the heat, get out of the kitchen.

—Harry S. Truman1

Phlogiston? Caloric? You don't hear much about either of these ideas anymore. There is good reason for this. They are abandoned scientific theories about the nature of heat. As we've seen, scientific hypotheses that don't pass the test of experimental evidence must be replaced. As Albert Einstein put it: “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.”2


Rats and debunked science. Used with permission from Sidney Harris.

Phlogiston and caloric bit the dust through the efforts of some characters you might be interested to meet. But first, we've got to set the scene.

Thanks largely to Galileo and Newton, 1700s physics had escaped the erroneous ideas of the old Greek philosophers and was charting a new course with a solid intellectual framework. But chemistry? Not so much. Chemists were still stuck with the elements fire, air, earth, and water, with some medieval alchemists’ arcane rumblings and symbolism tossed in. As an example, combustion and heat were not sorted out as being separate. German scientist Johann Joachim Becher (1635–1682) proposed an idea that was modified by Georg Ernst Stahl (1659–1734), who renamed one of Becher's concepts phlogiston.

Here's how they thought phlogiston fit into the picture: Every combustible substance contains some component of the universal element fire. This component was called phlogiston, from the Greek word for inflammable. For example, if some combustible substance such as wood lost weight when it burned, Stahl figured it was the result of a loss of some of the wood's phlogiston. Heating also involved phlogiston but was more complicated. We aren't going to expend much energy trying to understand it; the theory is wrong.

Let's meet the fellow who knocked phlogiston for a loop: Antoine-Laurent Lavoisier (1743–1794).


Antoine Lavoisier (1743–1794). By Jacques-Louis David (1748–1825) and James Caldwell (1739–1822). From Wikimedia Commons, user Uopchem25NirajPatel.

Antoine-Laurent Lavoisier was born in Paris in 1743 to Jean-Antoine and Emilie Punctis Lavoisier. He studied arts, the classics, and science at Mazarin College starting at age eleven. He achieved a law degree at age twenty, following the wishes of his father, but his interest in science prevailed, and he was elected to the Academy of Sciences at age twenty-five. At the same time, he used part of the inheritance from his mother to purchase a share in Ferme générale, a company that advanced estimated taxes to the French government, then collected them from citizens—a practice called tax farming. Lavoisier was an administrator, and one of his colleagues at Ferme générale was Jacques Paulze. In 1771, Paulze's thirteen-year-old daughter received a marriage proposal from Count d'Amerval, who was over fifty and physically repulsive. After threats to his job, Paulze approached Lavoisier with the proposition that he marry Marie-Anne Pierrette Paulze so she could avoid the unwanted advances of Count d'Amerval. Lavoisier had been so studious that his social life was neglected. Besides, Marie-Anne was intelligent, lively, and happened to be very attractive.

Lavoisier accepted. The convent-educated Marie-Anne and Antoine were married in 1771. Several years later, he was appointed gunpowder administrator and built a state-of-the-art chemistry laboratory on the floor above their residence at the Armory. Marie-Anne had become interested in lab work, received formal training, and then assisted Lavoisier in his laboratory research. Additionally, she had artistic skills and drew sketches and engravings of his lab apparatus. Her knowledge of languages was also important, as she translated scientific papers from English to French so her husband could read them. They operated as a well-oiled team.


Marie-Anne Paulze Lavoisier (1758–1836) and Antoine Lavoisier. By Jacques-Louis David (1748–1825). From Wikimedia Commons, user Crisco 1492.


The Lavoisiers produced some of the first quantitative chemical measurements, carefully weighing reactants and products in sealed glass vessels. In his 1777 paper Réflexions sur le phlogistique (Reflections on Phlogiston) (sent to the Royal Academy of Sciences in 1783), Lavoisier attacked the phlogiston theory. His careful measurements showed an increase of mass when substances burned (later understood as oxidation), not the decrease that was predicted by the phlogiston theory. His work was highly regarded and spelled the end for phlogiston. Lavoisier and his wife reportedly burned Stahl's books in celebration. Lavoisier also set the stage for collaboration with noted chemical experimenter Joseph Priestly about what had been called dephloghisticated air (horrid word) as actually being an element, one that Lavoisier named oxygen. He also named another element hydrogen, which combined with oxygen to produce water and which thus could no longer be regarded as one of the primary elements. These findings dealt a serious blow to the old four-element grouping of fire, air, earth, and water, and earned Lavoisier the title of “Father of modern chemistry.” Also, by identifying combustion as actually a combination with oxygen, Lavoisier showed that not all heat entails combustion. He called heat a “subtle fluid” that he named caloric. Lavoisier postulated that the total quantity of caloric in the universe is constant and simply flows from hotter bodies to cooler ones. In his experiments, he was one of the first to measure heat flow using an instrument called a calorimeter.

While Lavoisier made significant strides in chemistry, the society around him was in great turmoil. The French Revolution made sweeping changes to French society, including the arrest of all former tax gatherers. Lavoisier was tried, convicted, and guillotined in 1794, along with his father-in-law, Jacques Paulze. Lavoisier's death horrified his scientific colleagues. Mathematician Joseph-Louis Lagrange said, “It took them only an instant to cut off his head, but France may not produce another such head in a century.”3


To see the man who had a phenomenal impact not only on Lavoisier's work but also his personal life, we'll have to travel across the Atlantic Ocean. At first, such a connection will seem extremely unlikely, but stay tuned, your patience will be rewarded. That man was Benjamin Thompson (1753–1814).


Benjamin Thompson (1753–1814). From Wikimedia Commons, user Kelson.

More than a hundred years had elapsed since the Thompson family arrived from England and began farming near Woburn, Massachusetts. They were diligent farmers, well respected and moderately successful. Into this unremarkable family, Benjamin Thompson was born in 1753. Who would have dreamed he would become such a flamboyant character?

Benjamin's father, also named Benjamin, died within two years of his son's birth. Benjamin's mother remarried quickly. Young Benjamin became quite self-reliant at a very early age. Although he excelled at scientific studies and expressed himself with great facility, Benjamin didn't progress very far in school. Yet he resolved he would never be a farmer.

Thompson went to Salem at age thirteen to become a shopkeeper's apprentice. One of his duties involved working with gunpowder, and on one unfortunate occasion a batch of it exploded, seriously injuring Thompson. After he recuperated, he went to Boston to become a doctor's apprentice. That didn't work out either, so he decided to try his hand at teaching. Although he wasn't accepted as a student there, he and his lifelong friend Loammi Baldwin sat in on a few scientific lectures at Harvard.

Thompson then moved to Rumford, New Hampshire (now Concord), to take a teaching job. In Rumford, he lived with the new school's headmaster, Timothy Walker. Walker was delighted to have this tall, handsome new teacher with such genteel manners. Sarah Walker Rolfe, the minister's recently widowed daughter, was even more taken with Thompson. She was fourteen years Thompson's senior and, through inheritance from her late husband, the largest landowner in Rumford. Thompson must have also been pleased; within months of his arrival, he was married to Sarah. Moving easily into Sarah's circle of friends, Thompson became almost instantly acquainted with New Hampshire's governor, John Wentworth. The governor was mightily impressed and appointed Thompson to the rank of major in the local militia, the Second Provisional Regiment. Soon, Sarah delivered a daughter, Sarah, whom they called Sally.


With the colonist/loyalist conflict brewing, Thompson's evident sympathy for England and his promotion over older men created great animosity within his militia command. After being charged with “being unfriendly to the cause of liberty,” he was acquitted, but his unpopularity grew worse.4 Finally, he avoided a mob by abandoning his wife and daughter in Rumford. Thompson went to Boston to join the Loyalist forces. He knew the Massachusetts area and the colonial defenses well, so he was invaluable to the British forces. The siege of Boston did not go well for the Crown, and soon the British troops, including Thompson, were evacuated to England. There, Thompson almost immediately linked up with the secretary of state for colonial affairs, Lord Germain. Thompson worked his way up the ladder quickly to become undersecretary of state. With the Revolutionary War raging, doesn't it seem strange that a young former colonial militia officer would be welcomed into the heart of the British war effort, becoming an assistant to the secretary of state? Perhaps he shared his knowledge of the colonists’ plans, fortifications, and defenses. In his spare time, Thompson continued to pursue his scientific interests. A particular set of experiments involving improvement of gunpowder secured his election to the Royal Society in 1779. After Lord Germain's forced resignation—he was the least-respected member of prime minister Lord Frederick North's unpopular administration—Thompson was reassigned. Given the rank of lieutenant colonel, he was sent back to the colonies for a brief stint at a British garrison—The King's American Dragoons—in South Carolina and Manhattan. The war concluded soon—in favor of the colonials—and Thompson scurried back to England. For his service to the Crown, Thompson was made a colonel and granted a half-pay lifetime pension.

Since England's war had ended, Thompson decided to seek more military employment. Soon, he departed for Europe where he made contact with Elector Karl Theodor of Bavaria, who was just about to take office in Munich. Amazingly quickly, Thompson became a special confidant to the elector and ultimately became his principal adviser. When he asked for permission from the English military establishment for this new post, it was speedily granted, and Thompson was unexpectedly knighted by King George III. Perhaps the king thought military information from the Continent would be valuable. Of course, information flows both ways, as the elector well knew.

During his time in the elector's service, Sir Benjamin reformed the Bavarian military. Part of his plan was to provide them with decent uniforms and good food. Another part was to rid the Munich streets of beggars by giving them jobs making military uniforms. The elector desired reforms but had been unable to institute any before Thompson arrived, so he was delighted. The lower class was also delighted to get work and food and gave Thompson great support from then on. As another public project, Thompson obtained nine hundred acres of land for a beautiful park on the north end of Munich that became known as English Garden.

In his spare time, Thompson continued his scientific pursuits by performing experiments and writing papers for the Philosophical Transactions of the Royal Society. The elector rewarded his efforts by making him a count in 1791. Sir Benjamin chose the title Count Rumford to honor the site of his first success. Before long, political opponents and the threat of war (Austria and France were spoiling for a fight) weighed heavily, so Rumford toured Europe, including England. There, he invented the Rumford Fireplace to please his good friend Lady Palmerston. The new fireplace was vastly more efficient and far less smoky than conventional ones. He also designed improved ovens and stoves.

Back in New Hampshire, Rumford's wife died. Their daughter Sally had reached the age of majority and had just learned of her father's whereabouts. After receiving a letter from Sally, Rumford invited her to visit him. When she arrived, her lack of sophistication displeased him, and he promptly sent her to a finishing school.

A short time later, war raged across the European continent. Austria and France were at war with each other, and both armies were on the move near Munich. Although Munich was technically neutral, the elector fled for his life and sent for Rumford. Rumford returned to Munich with Sally and took charge of the Bavarian Army to organize its defenses. As the Austrians laid siege to Munich in 1796, Rumford rode out of the city to talk to the Austrian commander. Evidently, his well-outfitted and trained army of twelve thousand men convinced the Austrians (and the French) to keep right on marching. He became a local hero, and the elector made Sally Countess Rumford, possibly the first American-born countess.


In one of his many duties for the elector, Count Rumford supervised a factory where brass cannons were manufactured. Drilling out the barrel was a heat-generating process that required a lot of cooling water. Rumford noticed that the heating continued as long as the drill was turning, even if a blunt drill was used and no metal removed. According to the caloric theory, caloric was leaving the brass, but since the heating effect appeared to be limitless, Rumford concluded that there was no such thing as caloric; the mechanical action of the drill had been converted to heat. In 1798, he wrote a paper for the Royal Society, titled “An Experimental Enquiry concerning the Source of the Heat Which Is Excited by Friction.” This paper spelled the beginning of the end for Lavoisier's concept of caloric. It required another forty years more for details of the kinetic theory to be worked out by physicist James Prescott Joule, but eventually the kinetic theory fully replaced the caloric hypothesis of Lavoisier. Heat was no longer viewed as a subtle fluid but as simply the motion of molecules.


Count Rumford. Used with permission from Sidney Harris.

In 1799, Elector Karl Theodor died. Since he had been roundly disliked by the Bavarians, this appeared to be a good time for Count Rumford to move on. He went back to England and helped found the Royal Institution (not to be confused with the Royal Society, which has similar aims but is older). The first lecturer of the Royal Institution, Humphry Davy (1778–1829) was firmly on the side of the kinetic theory, saying heat was the “vibration of the corpuscles of bodies.”5 Before long, Count Rumford had personality conflicts with the more senior members at the Royal Institution, so he left. He traveled to Paris where he attended entertainments, some of which were given by Lavoisier's wealthy widow Marie-Anne Pierrette Paulze Lavoisier. Their friendship blossomed into marriage, but their styles turned out to be quite different. She enjoyed the social life, while he preferred to tinker with household gadgets.

The quarrels started almost immediately. It was reported that he locked the gates and hid the keys just before one of her parties, and she retaliated by pouring boiling water on his favorite rose collection. Before long, they separated and divorced. Marie-Anne moved out, and Rumford took up residence in the Paris suburb of Auteuil.

Bonus Material: Lavoisier/Thompson Internet interview. See To Dig Deeper for details.

In summary, Benjamin Thompson disproved Antoine Lavoisier's caloric theory, married and divorced his widow, and spent the remainder of his life in Paris. Not bad for a Massachusetts farmer, eh?


So, what was Benjamin Thompson/Count Rumford: soldier, scientist, spy, statesman, Lothario, or what? Biographer Stephen G. Brush has said that Count Rumford “had the most unpleasant personality in the whole of science since Isaac Newton.”6 On the other hand, Rumford donated money for the Rumford Medal to be awarded by the Royal Society (he won the first one); the Rumford Prize, awarded by the American Academy of Arts and Sciences; and the Rumford Professorship at Harvard. Franklin Delano Roosevelt said, in a 1932 interview, “Many-sided men have always attracted me…Thomas Jefferson, Benjamin Franklin, and Count Rumford are the three greatest minds America has produced.”7 Roosevelt's admiration was shared by many in England, Bavaria, France, and Massachusetts. But what would Lavoisier have thought about Rumford's demolition of his caloric theory as well as Rumford's marriage and divorce of his beloved Marie-Anne?

Leaving marriage and divorce behind, we will next turn to birth. The periodic table was born, but not without a few pains.