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| Lavoisier |
Antoine Laurent de Lavoisier is considered the father of modern Chemistry, having introduced the quantitative method into this science. In 1768, aged 25, he was elected a member of the Academy of Sciences. The astronomer Joseph Jérôme Lalande, who defended his candidacy, explained it this way:
A young man with knowledge, ingenuity, activity, whom fortune
exempts from practicing another profession, would naturally be of great use to
the sciences.
Indeed, his mother’s family inheritance allowed him to buy a position in a financial company called Ferme générale, whose members were responsible of collecting taxes on behalf of the king, a position he held until 1791 and which eventually led him to the grave. Here he met his future wife, Marie-Anne Paulze, whom he married in 1771 when she was 13, who became his best scientific collaborator.
His greatest success was the theory of oxidation. Until then it was thought
(according to the phlogiston theory, by Georg Ernst Stahl) that when a body
burns or oxidizes, it loses part of its substance. Lavoisier showed that what
happens is precisely the opposite: when a body burns it combines with a gas,
oxygen, a name invented by Lavoisier. He is also the author of the law of conservation of matter:
Matter is neither created nor destroyed. And water cannot become
earth.
Lavoisier asserted that the bodies called
metallic earths are not simple, but oxides. After repeating the experiment of
Henry Cavendish, discoverer of hydrogen, he said that water is not a simple
body, but a compound of oxygen and hydrogen, a name also invented by Lavoisier.
He redefined the concept of chemical element. Since ancient times everyone
spoke about four elements: earth, water, air, and fire. After the experiments
of Lavoisier and his predecessors, it was shown that water and air are not
elements. Lavoisier defined a chemical element as a substance that cannot be
decomposed, and proposed a list that included oxygen, hydrogen, nitrogen,
sulfur, phosphorus, mercury, and zinc, although he also included light and
heat, which we now know are not chemical elements, but forms of energy.
At the beginning of the French Revolution,
Lavoisier was appointed national commissioner of the committee for the
uniformity of weights and measures, which promoted the establishment of the
metric system. In 1791 the tax collection department was abolished and
Lavoisier lost his living. On November 24, 1793, the Revolutionary Convention
decreed the imprisonment of those who had held the position of tax collector.
There were requests advocating the release of Lavoisier. The Weights and
Measures Commission sent a letter in his favor. The Commission said that the work... was interrupted by the arrest of this citizen
and it was urgent for him to return to carrying out important work that he has
always carried out with zeal and activity. The response was the
expurgation of the Commission: Borda, Lavoisier, Laplace, Coulomb, Brisson and
Delambre were immediately dismissed.
When the tax collectors were sent to
trial, some of the defendants planned to commit suicide with an excessive dose
of opium, and offered it to Lavoisier, who dissuaded them thus:
Why should we anticipate death? Is it shameful to receive it by an
unjust order? The excess of injustice erases shame... To commit suicide would
be to absolve those who send us to death. Let us think of those who have
preceded us and let us also set a good example for those who follow us.
These words by Lavoisier convinced his
companions, none of whom committed suicide. Thanks to this, one of them saved
his life, because he was not sentenced with the others.
It is said that when Hallé, defender of
the accused, presented a report recalling the scientific works of Lavoisier,
Jean-Baptiste Coffinhal, vice president of the Revolutionary Tribunal, answered
this:
The Republic does not need wise men; justice must follow its
course.
The collectors were sentenced to death on May 8, 1794, and that same day they all died by guillotine.
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| Lagrange |
The next day, when
the news broke, Joseph Louis de Lagrange, director of the commission that
established the metric system, exclaimed:
A moment has sufficed to cut off his head, and perhaps a century
will not suffice to produce another like it.
Less than a year after the execution,
Lavoisier’s widow petitioned the Convention for the return of her husband’s
property that had been confiscated, leaving her destitute, and when it was
granted, the restitution order had the following phrase:
Widow of Lavoisier, unjustly condemned.
Lavoisier was a devout Catholic all his
life. A note written by his widow says this:
It was [in his laboratory] where one had to see and hear this
man with such a just spirit, such a pure talent, such a high genius; it was in
his conversation that one could judge the height of his moral principles.
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