Daily MOS: Phlogiston, the Father of Chemistry, and the Guillotine

A mock fire warning sign labeled with phlogiston instead of fire, captioned 'teach the controversy.'

I’m sure a few of us in high school chemistry must have said we’d like to send the guy who invented stoichiometry to the guillotine.

Well. Um.

Today’s Moment of Science… Vive la revolution!

Nebulously defined due to lack of existence, chemists in the 1700s commonly believed phlogiston to be contained in every flammable body, waiting to be released upon combustion. What was phlogiston made of, you ask? At this point in history, you’re working with earth, air, water, and fire. So maybe it was a fire-like element, released on combustion. Why did a candle go out when you put a glass on top of it? Because the air became choked with the phlogiston the candle had released, obviously.

We were still a few hundred years away from the breakthrough of the lobotomy, so.

Antoine-Laurent de Lavoisier was a French nobleman born in 1743. He went to law school and then did what all my lawyer friends assure me they wish they’d done: immediately changed careers. Lavoisier’s passion was chemistry, the still burgeoning science that didn’t have its legs beneath it. He did something that allowed his research to flourish; he inherited money and married into even more of it. Furthermore, he worked for something in France called the Ferme Générale, or General Farm, which google assures me has nothing to do with agriculture. It was the government’s outsourced tax collecting system.

Yeah there’s no writing on the wall here with ‘nobleman faffing about in his lab and collecting taxes for a living in pre-revolution France’ or anything. But we press on.

So while peasants starved, Lavoisier went to work out how fire happened. He’d read studies with evidence of burned substances gaining mass after burning, which flew in the face of phlogiston theory. Lavoisier got to work.

Replicating the work of natural philosopher Joseph Priestly, he experimented with metals like sulfur and phosphorus and observed them get heavier after combustion. The weight gain as a result of turning into metal oxides was something that couldn’t be fit into the phlogiston theory. He figured there must be something in the air that they were reacting with. He experimented further, trapping and measuring the gas that escaped when he applied heat to metal oxides. The air they released was referred to as ‘dephlogisticated air’ which is my new band name.

He theorized the air was made of multiple components, one of which created fire, another extinguished it. He isolated and give a name to oxygen, from latin meaning ‘acid forming.’ He also figured out that water was not an element, but made of oxygen and hydrogen. He burned a diamond in a controlled environment and found the total mass didn’t change, leading him to the law of conservation of mass. Armed with this load of evidence, his work sounded the death knell for phlogiston theory. But he wasn’t done there.

His last major work was Traité élémentaire de Chimie (Elements of Chemistry), published in 1789. It was the chemistry text that started laying the framework for modern times. Included were principles behind stoichiometry, how gases react, basic nomenclature standardization, and a humble ‘table of simple substances,’ the barest of bones for the entire periodic table of the elements.

Remember how much of a pain getting through your chemistry text book was? This guy showed up and there was no textbook yet, we were still pretty fuzzy on what an element was, and he sorted out like a third of the concepts you learned in high school chem. One fucking guy.

We obviously couldn’t let him live.

The same year that Elements of Chemistry was published, revolutionaries stormed the Bastille. In time, everyone at the General Farm was arrested and tried. His day job would be his undoing, and Antoine Lavoisier was beheaded via guillotine on May 8th, 1794.

It’s damn near impossible to tease out if any one contribution from Antoine Lavoisier was his most important to the field of chemistry. But I’m personally most thankful I don’t have to pronounce phlogiston.

This has been your daily Moment of Science, and your reminder guillotines are best left in 1700s France.

A mock fire warning sign labeled with phlogiston instead of fire, captioned ‘teach the controversy.’
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About SciBabe 375 Articles
Yvette d'Entremont, aka SciBabe, is a chemist and writer living in North Hollywood with her roommate, their pack of dogs, and one SciKitten. She bakes a mean gluten free chocolate chip cookie and likes glitter more than is considered healthy for a woman past the age of seven.

4 Comments

  1. This is a great article, but how could you leave out the part about his wife and colleague Marie Lavoiseur? They worked together on most of their discoveries, and Marie had the vital role of translating Antoine’s books into English so that they could reach a broader audience.

  2. “The weight gain as a result of turning into metal oxides was something that couldn’t be fit into the phlogiston theory.”

    Oh, they tried! It was seriously suggested that phlogiston had a negative mass.

  3. What always amazes me about people like Lavoisier is that they “went first”. they discovered something for the first time. As a reasonably intelligent person whose brain just doesn’t work this way, I have always admired the people who could observe and experiment and come up with something completely new. Also, Phlogiston sounds likes a former Soviet republic. I will stop now as I really don’t want to phlog the issue.

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