French physicist
Jean-Baptiste Biot
(
;
[2]
French:
[bjo]
; 21 April 1774 ? 3 February 1862) was a
French
physicist
,
astronomer
, and
mathematician
who co-discovered the
Biot?Savart law
of magnetostatics with
Felix Savart
, established the reality of
meteorites
, made an early balloon flight, and studied the
polarization of light
.
The
biot
(a
CGS
unit of electrical current), the mineral
biotite
, and
Cape Biot
in eastern
Greenland
were named in his honour.
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
Ecole 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
College de France
around 1800, and three years later was elected as a member of the
French Academy of Sciences
. In July 1804, Biot joined
Joseph Louis Gay-Lussac
for the first scientific hot-air balloon ride to measure how the Earth's magnetic field varies with elevation (NNDB 2009, Reese 2004,
[5]
O'Connor and Robertson 1997). They reached a height of 4000 metres (13,100 feet) (NNDB 2009, Reese 2004). Later, in Sept. 1804, a solo flight took Gay-Lussac up to 7010 metres (23,000 ft) (quite dangerous without supplementary oxygen (Reese 2004)).
Biot was also a member of the
Legion of Honour
; he was elected chevalier in 1814 and commander in 1849. In 1815, he was elected a Foreign Member of the
Royal Society
of London,
[6]
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
.
[7]
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
.
[8]
[9]
Jean-Baptiste Biot had a single son,
Edouard Constant Biot
, an engineer and Sinologist, born in 1803. Edouard died in 1850 and his father made extraordinary efforts to ready for publication the second half of Edouard's last book, a reference translation of the Chinese classic
Tcheou-li
. 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 visited many workshops and questioned artisans and craftsmen about their methods and vocabulary in order to verify his son's work. Biot's translation remains to this day the only translation into a Western language of this book.
He died in
Paris
on 3 February 1862.
Work
[
edit
]
Electromagnetism
[
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]
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
Felix Savart
for their work in 1820.
[10]
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).
Meteorites
[
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]
In 1803 Biot was sent by the
Academie francaise
to report back on 3000
meteorites
that fell on
L'Aigle
, in
Normandy
, France (see
L'Aigle (meteorite)
). He found that the meteorites, called "stones" at the time, were from outer space.
[11]
With his report, Biot helped support the German physicist
Ernst Chladni
's argument, published in 1794, that meteorites were debris from space.
[12]
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 Ernst Chladni published a book claiming that such rocks had an extraterrestrial origin (Westrum). Only after Biot was able to analyse 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."
[13]
[14]
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.
[15]
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 bitartrate
was first discovered inside 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.
Selected writings
[
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]
See also
[
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]
Notes
[
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]
- ^
O'Connor, John J.;
Robertson, Edmund F.
,
"Jean-Baptiste Biot"
,
MacTutor History of Mathematics Archive
,
University of St Andrews
- ^
"Biot-Savart law"
.
Random House Webster's Unabridged Dictionary
.
- ^
C D Waterston; A Macmillan Shearer (July 2006).
Former Fellows of The Royal Society of Edinburgh, 1783?2002: Part 1 (A?J)
(PDF)
.
Royal Society of Edinburgh
.
ISBN
090219884X
. Archived from
the original
(PDF)
on 24 January 2013
. Retrieved
18 September
2015
.
- ^
Appletons' annual cyclopaedia and register of important events of the year: 1862
. New York:
D. Appleton & Company
. 1863. p. 683.
- ^
K. M. Reese, Chemical & Engineering News, Vol 82 (2004)
https://cen.acs.org/articles/82/i25/Newscripts.html
- ^
"Fellow details"
.
Royal Society
. Archived from
the original
on 5 November 2018
. Retrieved
19 May
2016
.
- ^
"Book of Members, 1780?2010: Chapter B"
(PDF)
.
American Academy of Arts and Sciences
. Retrieved
8 September
2016
.
- ^
"Review of
Anecdote relative a M. de Laplace
par Jean Baptiste Biot"
.
The Quarterly Review
.
87
: 115?118. June 1850.
- ^
Biot, J. B. (1816).
"
Anecdote relative a M. de Laplace
"
.
Journal des savants
: 65?71. Fevrier 1850
{{
cite journal
}}
: CS1 maint: postscript (
link
)
- ^
A joint Biot-Savart paper "Note sur le magnetisme de la pile de Volta" was published in the
Annales de chemie et de physique
in 1820.
- ^
J.B. Biot (1803)
Relation d'un voyage fait dans le departement de l'Orne, pour constater la realite d'un meteore observe a l'Aigle le 26 floreal an 11
[Account of a journey made in the department of the Orne [River], in order to ascertain the reality of a meteor observed in l'Aigle on the 26th of Floreal in the year 11 [Note: The date "26 floreal" on the title page is a typographical error; the meteor shower actually occurred on
6
floreal (i.e., April 26, 1803) and everywhere else in the text the date "6 floreal" is given as the date of the meteor shower. (Paris, France: Baudouin, 1803).
- ^
Chladni, Ernst Florens Friedrich,
Uber den Ursprung der von Pallas gefundenen und anderer ihr ahnlicher Eisenmassen und uber einige damit in Verbindung stehende Naturerscheinungen
[On the origin of the iron masses found by
Pallas
and others similar to it, and on some natural phenomena associated with them] (Riga, Latvia: Johann Friedrich Hartknoch, 1794). Available on-line at:
Saxon State and University Library at Dresden, Germany
.
- ^
Biot, J. B. (1815)
"Phenomene de polarisation successive, observes dans des fluides homogenes"
(Phenomenon of successive polarization, observed in homogeneous fluids),
Bulletin des Sciences, par la Societe Philomatique de Paris
, 190?192.
- ^
Jean-Baptiste Biot ? Florida State University
- ^
Frankel 2009
References
[
edit
]
- Frankel, Eugene. "Corpuscular Optics and the Wave Theory of Light: The Science and Politics of Revolution in Physics."
Social Studies of Science
vol. 6, no 2. May 1976. Sage Publications, Ltd. 15 June 2009 <
https://www.jstor.org/stable/284930
>.
- Westrum, Ron. "Science and Social Intelligence about Anomalies: The Case of Meteorites."
Social Studies of Science
vol. 8, no.4 Nov. 1978. Sage Publications, Ltd. 15 June 2009 <
https://www.jstor.org/stable/284819
>.
- Parsley, Robert J. "THE BIOT-SAVART OPERATOR AND ELECTRODYNAMICS ON BOUNDED SUBDOMAINS OF THE THREE-SPHERE". University of Pennsylvania. <
http://users.wfu.edu/parslerj/research/dissertation.parsley.pdf
>
Further reading
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External links
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