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Pierre Bouguer

 
Scientist: Pierre Bouguer

French physicist and mathematician (1698–1758)

Bouguer, the son of a hydrographer and mathematician, was born in Le Croisic, France, and followed into his father's profession. He was a child prodigy and obtained a post as professor of hydrography at the remarkably early age of 15. The study of the problems associated with navigation and ship design was his chief interest. Bouguer took part in an extended expedition to Peru led by Charles de la Condamine to determine the length of a degree of the meridian near the equator. While on this expedition Bouguer also did a great deal of other valuable experimental work.

One of Bouguer's most successful inventions was the heliometer to measure the light of the Sun and other luminous bodies. Although it was not his chief interest the research for which Bouguer is now best remembered was on photometry. Here too he did much valuable experimental work and one of his major discoveries was of the law now named for him. This states that in a medium of uniform transparency the intensity of light remaining in a collimated beam decreases exponentially with the length of its path in the medium. The law is sometimes unjustly attributed to Johann Lambert. Bouguer's work in optics can be seen as the beginning of the science of atmospheric optics.

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Columbia Encyclopedia: Pierre Bouguer
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Bouguer, Pierre (pyĕr būgĕr'), 1698-1758, French mathematician and hydrographer. He made some of the first photometric measurements, calculating the intensity of the light of the sun as compared with that of the moon, and invented (1748) the heliometer. His works include Essai d'optique sur la gradation de la lumière (1729) and La Figure de la terre (1749).
Wikipedia: Pierre Bouguer
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Pierre Bouguer. Jean-Baptiste Perronneau, 1753.

Pierre Bouguer (February 16, 1698August 15, 1758) was a French mathematician, geophysicist, geodesist, and astronomer. He is also known as "the father of naval architecture".

His father, Jean Bouguer, one of the best hydrographers of his time, was regius professor of hydrography at Croisic in lower Brittany, and author of a treatise on navigation. In 1713 Pierre was appointed to succeed his father as professor of hydrography. In 1727 he gained the prize given by the French Academy of Sciences for his paper On the masting of ships, beating Leonhard Euler; and two other prizes, one for his dissertation On the best method of observing the altitude of stars at sea, the other for his paper On the best method of observing the variation of the compass at sea. These were published in the Prix de l’Academie des Sciences.

In 1729 he published Essai d'optique sur la gradation de la lumière, the object of which is to define the quantity of light lost by passing through a given extent of the atmosphere, and became the first known discoverer of what is now more commonly known as the Beer-Lambert law. He found the light of the sun to be 300 times more intense than that of the moon, and thus made some of the earliest measurements in photometry. In 1730 he was made professor of hydrography at Havre, and succeeded Pierre Louis Maupertuis as associate geometer of the Academy of Sciences. He also invented a heliometer, afterwards perfected by Joseph von Fraunhofer. He was afterwards promoted in the Academy to the place of Maupertuis, and went to reside in Paris.

In 1735 Bouguer sailed with Charles Marie de La Condamine on a scientific mission to Peru, in order to measure a degree of the meridian near the equator. Ten years were spent in this operation, a full account of which was published by Bouguer in 1749, Figure de la terre determine. In 1746 he published the first treatise of naval architecture,Traite du navire, which among other achievements first explained the use of the metacenter as a measure of ships' stability. His later writings were nearly all upon the theory of navigation and naval architecture.

A crater on Mars was named in his honor. A lunar crater was also named after him.

His name is also recalled as the meteorological term Bouguer's halo (also known as Ulloa's halo, after Antonio de Ulloa, a Spanish member of his South American expedition) which an observer may see infrequently in fog when sun breaks through (for example, on a mountain) and looks down-sun -- effectively a "Fog bow" (as opposed to a "rain-bow"). An infrequently observed meteorological phenomenon; a faint white, circular arc or complete ring of light that has a radius of 39 degrees and is centered on the antisolar point. When observed, it is usually in the form of a separate outer ring around an anticorona. Reference: Tricker, R. A. R., 1970: An Introduction to Meteorological Optics, pages 192–193.

References

  • Ferreiro, Larrie. "Ships and Science: The Birth of Naval Architecture in the Scientific Revolution, 1600-1800". Cambridge: MIT Press, 2007
  • Lamontagne, Roland. "La vie et l’oeuvre de Pierre Bouguer (The life and work of Pierre Bouguer)" Montreal: Presses de l’Université de Montréal, 1964
  • Lamontagne, Roland. "Pierre Bouguer, 1698-1758, un Blaise Pascal du XVIIIe siècle; Suivi d'une correspondence (Pierre Bouguer, 1698-1758, a Blaise Pascal of the 18th century; followed by correspondence)". Manuscript. Montreal: Université de Montreal, 1998

This article incorporates text from the Encyclopædia Britannica, Eleventh Edition, a publication now in the public domain.


 
 

 

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Scientist. A Dictionary of Scientists. Copyright © Market House Books Ltd 1993, 1999, 2003. All rights reserved.  Read more
Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/ Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Pierre Bouguer" Read more