Antoine Lavoisier (1743-1794) is often called the father of modern chemistry. Lavoisier lived during the French Revolution, and he brought about a scientific revolution in chemistry.
He is possibly the greatest scientist France ever produced, but his scientific eminence was not enough to save him from the guillotine in 1794.
The son of a wealthy Parisian lawyer, Lavoisier completed a law degree to please his parents, but his real interest was in science. In 1768 he was elected to the prestigious French Academy of Sciences in which he was a rising star, becoming director in 1785. Lavoisier was a part-time scientist. Realising he would never become wealthy out of chemistry, he joined Ferme General in 1768, a private company that collected taxes for the government. This work provided Lavoisier with a handsome income.
Tax collectors are unpopular. Lavoisier was also personally responsible for building a wall around Paris in order to facilitate tax collection. This prevented Parisians from leaving the city at night and it was very unpopular.
In the book On Giants' Shoulders by Melvin Bragg (Hodder and Stoughton, 1998), Peter Atkins, the noted UK chemist, credits Lavoisier as "The Father of Modern Chemistry" for three reasons. First, Lavoisier introduced a new language of chemistry, which swept away the old terminology based on the natural origins of things, such as flowers and trees - terminologies that said nothing about the chemical composition of the material.
Second, Lavoisier emphasised the fundamental distinction between elements and compounds and established the basic rules of chemical combination. One of his most famous experiments was a public demonstration that water is made up of the two elements, hydrogen and oxygen. Third, Lavoisier introduced precise measurement into chemistry and so turned it into an exact physical science.
Lavoisier is best remembered for overturning the theory of phlogiston. Phlogiston was a hypothetical substance, postulated in the 17th century to explain combustion. The theory held that combustible substances contain phlogiston and combustion is essentially the process of losing phlogiston. The British chemist Joseph Priestley (1733-1804) discovered that air is composed of several gases, one of which is essential to animal life, which Priestley called "dephlogisticated air". He generated it by heating mercuric oxide and collecting the gas that was given off. Priestley showed Lavoisier how to make dephlogisticated air.
Lavoisier re-named dephlogisticated air as oxygen. The emanation of oxygen from mercuric oxide suggested to Lavoisier that chemical decomposition could be quantified. He ran the experiment in both directions. First he burned mercury in oxygen and measured the amount of oxygen that combines with the mercury to make mercuric oxide.
Next he took the mercuric oxide and heated it to expel the oxygen, leaving mercury behind. When he measured the oxygen generated it was exactly the amount that had been taken up before. The overall process was revealed as the combination and uncoupling of fixed quantities of mercury and oxygen. Combustion of mercury was revealed as chemical combination with oxygen and phlogiston was no more.
The French revolutionaries eventually turned on tax collectors. Lavoisier probably felt reasonably safe. As a social reformer he had devised plans for fairer taxation, improved agriculture and old-age pensions. Nevertheless, in 1793 he was arrested and imprisoned. He was convicted of conspiring against the French people and guillotined on May 8th, 1794.
He pleaded for a couple of weeks stay of execution in order to complete some scientific work. The judge allegedly replied: "The revolution does not need scientists."
Two years later, when the terror was over, Lavoisier became a hero. A statue was unveiled and well-known scientists presented eulogies. In the short period of his imprisonment, Lavoisier showed great courage, and dignity. I will end by quoting his last letter to his cousin.
"I have enjoyed a reasonably long and, above all, a happy life and I trust my passing will be remembered with some regret and perhaps some honour.
What more could I ask for? I will probably be spared the troubles of old age by the events in which I find myself embroiled. I shall die while in my prime, which I count as another of the advantages I have enjoyed. My only regret is not having done more for my family. I am sorry to have been stripped of everything and to be unable to give you and others tokens of my affection and my remembrance.
Evidently it is true that living according to the highest standards of society, rendering important services to one's country and devoting one's life to the advancement of the arts and human knowledge is not enough to preserve one from evil consequences and dieing (sic) like a criminal.
I am writing today because tomorrow I may not be alive to do so and because I find it a comfort in these final moments to think of you and others who are dear to me. Be sure to tell those who are concerned about me that this letter is addressed to them all. It is probably the last I shall write." William Reville is associate professor of biochemistry and director of microscopy at UCC