Biography[edit]
Jean-Baptiste Biot was born in Paris on 21 April 1774 the son of Joseph Biot, a treasury official.[3]
He was educated at Lyceum Louis-le-Grand and École Polytechnique in 1794.[4] Biot served in
the artillery before he was appointed professor of mathematics at Beauvais in 1797. He later went on
to become a professor of physics at the Collège de France around 1800, and three years later was
elected as a member of the French Academy of Sciences. In 1804 Biot was on board for the first
scientific hot-air balloon ride with Gay-Lussac (NNDB 2009, O’Connor and Robertson 1997). They
reached a height of 7016 metres (23,000 feet), quite dangerous without supplementary oxygen.
Biot was also a member of the Legion of Honor; he was elected chevalier in 1814 and commander in
1849. In 1815, he was elected a Foreign Member of the Royal Society of London,[5] in 1816 a
member of the Royal Swedish Academy of Sciences, and 1822 a Foreign Honorary Member of
the American Academy of Arts and Sciences.[6] In addition, Biot received the Rumford Medal in 1840,
awarded by the Royal Society in the field of thermal or optical properties of matter. (O’Connor and
Robertson 1997). In 1850 Jean-Baptiste Biot published in the Journal des savants a 7-page memoir
from his recollections of the period of the late 1790s and early 1800s concerning his encounters
with Laplace.[7][8]
Jean-Baptiste Biot had a single son, Édouard Constant Biot, an engineer and Sinologist, born in
1803. Edouard died in 1850 and it was only thanks to the extraordinary efforts of his father that the
second half of Edouard's last book, the Chinese classic Tcheou-li, was readied for publication. It had
been left in manuscript, unfinished. To publish it in correct form, Jean-Baptiste Biot wrote, he had to
consult Stanislas Julien, the famous Sinologist, but also, especially for the translation of the most
difficult part, the Kaogongji, he himself had to visit many workshops and questioned artisans and
craftsmen about their methods and vocabulary in order to verify his son's work. To this day, Biot's
translation remains the only translation into a Western language of this book.
He died in Paris on 3 February 1862.
Work[edit]
Essai de géométrie analytique, 1826
Jean-Baptiste Biot made many contributions to the scientific community in his lifetime – most notably
in optics, magnetism, and astronomy. The Biot–Savart law in magnetism is named after Biot and his
colleague Félix Savart for their work in 1820.[9] In their experiment they showed a connection
between electricity and magnetism by "starting with a long vertical wire and a magnetic needle some
horizontal distance apart [and showing] that running a current through the wire caused the needle to
move" (Parsley).
In 1803 Biot was sent by the Académie française to report back on 3000 meteorites that fell
on L'Aigle, France (see L'Aigle (meteorite)). He found that the meteorites, called "stones" at the time,
were from outer space.[10] With his report, Biot helped support Ernst Florens Friedrich Chladni's
argument that meteorites were debris from space, which he had published in 1794.[11]
Meteorites[edit]
Biot in 1851
Prior to Biot's thorough investigation of the meteorites that fell near l'Aigle, France in 1803, very few
truly believed that rocks found on Earth could have extraterrestrial origins. There were anecdotal
tales of unusual rocks found on the ground after fireballs had been seen in the sky, but such stories
were often dismissed as fantasy. Serious debate concerning the unusual rocks began in 1794 when
German physicist Chladni published a book claiming that rocks had an extraterrestrial origin
(Westrum). Only after Biot was able to analyze the rocks at l'Aigle was it commonly accepted that
the fireballs seen in the sky were meteors falling through the atmosphere. Since Biot's time, analysis
of meteorites has resulted in accurate measurements of the chemical composition of the solar
system. The composition and position of meteors in the solar system have also given astronomers
clues as to how the solar system formed.
Polarized light[edit]
In 1812, Biot turned his attention to the study of optics, particularly the polarization of light. Prior to
the 19th century, light was believed to consist of discrete packets called corpuscles. During the early
19th century, many scientists began to disregard the corpuscular theory in favor of the wave theory
of light. Biot began his work on polarization to show that the results he was obtaining could appear
only if light were made of corpuscles.
In 1815 he demonstrated that "polarized light, when passing through an organic substance, could be
rotated clockwise or counterclockwise, dependent upon the optical axis of the material."[12][13] His work
in chromatic polarization and rotary polarization greatly advanced the field of optics, although it was
later shown that his findings could also be obtained using the wave theory of light (Frankel 2009).
Biot's work on the polarization of light has led to many breakthroughs in the field of optics. Liquid
crystal displays (LCDs), such as television and computer screens, use light that is polarized by a
filter as it enters the liquid crystal, to allow the liquid crystal to modulate the intensity of the
transmitted light. This happens as the liquid crystal's polarisation varies in response to an electric
control signal applied across it. Polarizing filters are used extensively in photography to cut out
unwanted reflections or to enhance reflection.
Cream of Tartar[edit]
Potassium tartrate was first discovered inside of a wine container in Iran. The modern application of
the substance began in 1768, and in 1832, Jean Baptiste Biot discovered the physical properties of
cream of tartar. The item gained most of its popularity when the French began using it frequently in
their cooking.
