The Taxman who Reinvented Chemistry

"It took them only an instant to cut off this head, and one hundred years might not suffice to reproduce its like," said mathematician Joseph Louis Lagrange about his colleague and friend Antoine Lavoisier, one of the greatest scientists of the 18th century, if not of our entire history, who was executed in Paris in May 1794, before his 51st birthday.

Antoine-Laurent de Lavoisier was born in Paris on August 26, 1743, to an affluent middle-class family. His grandfather and father were both successful lawyers, and his mother was a descendent of a family who had achieved success in the meat industry. His mother died when Antoine was only five years old, so he and his younger sister were cared for mostly by their grandmother.

Lavoisier studied law at the University of Paris, with the intention to continue the family tradition. Alongside his courses in law, he found time to study courses in astronomy, mathematics, botany, geology and chemistry. In 1764 he graduated and was admitted to practice law, but then finally realized that he found science more appealing.

He worked on completing a comprehensive geological survey of the map of France, and simultaneously made the first steps in a number of other scientific pursuits. By 1766 he already received a medal from the King of France on his work dealing with the problems of urban street lighting. That same year, the grandmother who raised him died and left Lavoisier her fortune (his sister died at the age of 15, so he had become the sole heir). He then carried on with his geological work, and there he proved many scientific capabilities, and at the age of only 25 he was elected to the Academy of Sciences.

Academy members were required to submit reports to the French government on various scientific subjects, and Lavoisier’s reports discussed different scientific fields from hot air balloons and rising gas from the sewage drains, to studying meteorites and how to grow cabbage.

Around the time Lavoisier was accepted to the Academy of Sciences, he spent some of the money he inherited on buying a share of a tax collecting company. The collection was made through private companies and handed to the government in return for the right to retain any amount collected beyond what was pledged to the King. It was a promising revenue stream and a good financial investment, but there was corruption in the field; many paid bribes to buy a share and used thugs for payment collections.

At first, the collection business benefited Lavoisier as it allowed him to continue his scientific work. In 1771 he even married the daughter of one of his colleagues, Marie-Anne Pierrette Paulze. He was 28, and the bride only 13-years old. Despite the age gap, they had a beautiful marriage, and Paulze studied chemistry and contributed to her husband’s research; she managed his documentation by record writing and hand-drawing sketches. On the occasion of their marriage, his father bought Lavoisier a title of nobility and he officially became "de Lavoisier".

What's burning?

After the marriage, Lavoisier began investigating combustion. He used a giant lens, more than a meter in diameter, to focus the light beams on different objects, and proved, for example, that a diamond can catch fire. He also showed that the gas generated after the disappearance of the diamond is a material that today we call carbon dioxide. Lavoisier realized that the charcoal, this gas and the diamond are all different forms of the same material, and called them "carbon". He also noticed that the amount of the material in a closed container does not change, and this finding eventually led him to formulate the law of conservation of matter, stating that the mass of a particular material does not disappear, even if it changes form.

Lavoisier was surprised to find that when sulfur and phosphorus burn, they increase in weight instead of losing weight as one might expect. After hearing of Joseph Priestley’s discovery of the element oxygen, or "pure air" as it was called then, Lavoisier’s research gained momentum, and in 1775 he published an article stating that the element that binds to metals during combustion is pure air. With these findings, Lavoisier disproved the idea that had been accepted originally that combustion material named phlogiston was released from all burning entities. Eventually, he also gave this element a name - oxygen (meaning "acid-forming" in Greek).

Fundamentals of chemistry

Performing basic experiments on animals, and even humans, with his colleague Pierre Laplace, Lavoisier discovered that through the breathing process oxygen becomes carbon dioxide. He went on with a brilliant study to show the heat index produced by some animals: he placed a guinea pig in a fully enclosed cage surrounded by ice and measured how much ice defrosted due to the animal's body temperature. He then examined a similar installation for coal and how much must be burned to defrost the same amount of ice and concluded that the amount of carbon emitted from the body of the animal is similar to the amount of carbon burned in the charcoal. He realized that animals maintain their body heat in a similar manner to a slow wood fire burn, and "burn" carbon using their food combined with the oxygen they breathe.

In addition to these ground-breaking findings, the study of Lavoisier was a milestone in the understanding that humans are not unique beings, but rather complex systems that obey the same laws as the rest of the natural world.

Lavoisier discovered several other revelations. He identified sulfur as a separate chemical element; revealed that water is not an element, but a compound of oxygen and "inflammable air", which he named "hydrogen" (meaning "creates water" in Greek). And from here he created a list of chemical elements, a kind of early version of the periodic table, while not without mistakes, but it was the first time there were scientific principles for the classification and determining the names of materials.

In 1789, Lavoisier published a summary of his research in chemistry in his masterpiece titled "Elementary Treatise of Chemistry" (Traité Élémentaire de Cehimie). This book laid the foundations of chemistry as an actual scientific discipline, and is still regarded as one of the most important texts in the history of science.

Reconstruction of Lavoisier's laboratory in a museum in Munich. In the center - the large lens for material combustion | Source: Wikipedia

‘Till the end

Simultaneously to his scientific work, Lavoisier was involved in governmental activities. In 1775, King Louis the 16th appointed him as one of his four commissioners of the gunpowder industry, to manage the business of its manufacturing while instituting reforms for the French army and navy that promised gunpowder quantity and quality, helping them manage the wars of France. In 1787 Lavoisier was elected to the Legislative Assembly of the Province of Orléans, where he performed his agricultural experiments and tried to introduce a fairer tax system.

Lavoisier supported most of the principles of the French Revolution that broke out in 1789. Despite the hatred felt toward tax collectors and the allegations of corruption for the gunpowder commission, he went on to serve his country. He was an important partner in planning educational reform, a board member of the bank that would eventually become the Central Bank of France, and a member of the committee that planned and eventually led to the metric system.

All his work for France and his scientific contribution did not help him when the new administration decided to prosecute tax collectors from before the revolution. He was arrested on May 8, 1794, and on that same day he was tried convicted and executed by guillotine, for stealing public funds and giving them to the enemies of France. According to a famous story, even at his execution he decided to conduct an experiment, and asked his assistant to count how many times his eyes blinked after they decapitated him. It is most likely the story was untrue, but this legend is indicative of the special nature of Lavoisier and his devotion to scientific research.

A year and a half after the execution, Lavoisier was acquitted on all counts. While it was too late for him, history has recognized his importance. Today his sculptures are placed all over France and in other countries, educational institutions and important scientific awards are named in his honor and he is among the 72 French scientists and engineers whose names are engraved on the Eiffel Tower - one of the symbols of modern France. These things illustrate just some of the importance of who is considered – and rightly so - the father of modern chemistry.