Thomas Young
See also: Young
Thomas Young (1773 - 1829), is a Physicien, Médecin and British Egyptologist .
Its excellence in many fields not connected makes that he is regarded as a Polymathe, on the same basis for example as Léonard de Vinci, Gottfried Leibniz or Francis Bacon. Its knowledge was so vast that it was known under the name of phenomenon Young .
He exerted the Médecine all his life, but he is especially known for his definition of the Modulus Young in Science of the materials and for his experiment of the Fentes of Young in Optique, in which he highlighted and interpreted the phenomenon of luminous Interférence S.
It was also interested in the Egyptology while taking part in the study of the Pierre de Rosette.
Biography
Young comes from a family of Quakers of Milverton, in the Somerset, where it was born the June 13rd 1773, the last of ten children. At the fourteen years age he already speaks in addition to the English the French, the Italian , the Latin , the Greek , the Hebrew , the Chaldéen, the Syriaque, the Araméen Samaritan, the Amharique, the Turkish , the Arab and the Persan.
Young starts to study medicine in 1792 with London, share in 1794 with Edinburgh, then one year later with Göttingen, where it obtains the title of doctor in Physique in 1796. In 1797 it enters to the Emmanuel College to Cambridge. The same year he inherits the property of his great-uncle, Richard Brocklesby, which makes it financially independent. In 1799 it settles as a doctor in London. Young anonymously publishes many of his first articles to protect his reputation as a doctor.
In 1801 Young is named professor of natural Philosophie with the Royal Institution. It gives 91 conferences in two years. In 1802 it is also named foreign secretary of the Royal Society, of which it was elected member in 1794. It gives up professorship in 1803, fearing that does not interfere with its practice of medicine. Its conferences are published in 1807 under the title Conférences on natural philosophy and anticipate certain future theories.
In 1811 it takes a post of doctor to the St George' S Hospital, and in 1814 it takes part at a committee for the study of the dangers related to the generalized introduction of lighting to gas in London. In 1816 he is secretary of a charged commission to evaluate the length of the pendulum of which the period is worth two seconds (what makes it possible to deduce acceleration from it from the Pesanteur at the place of the experiment). In 1818 he becomes secretary of the Board off Longitude and superintendant HM Nautical Almanac Office.
A few years before its death it is interested in the Assurance-vie, and in 1827 it is selected like one from eight associated abroad of the Academy of Science of the Institut of France.
Thomas Young dies in London the May 10th 1829.
Research tasks
Slits of Young
See also: Slits of Young
The contribution of Young to the field of the Optique is undoubtedly its greater reason for celebrity, in particular her famous experiment of the double slit. In 1801, it makes pass a beam of light through two parallel slits, and projects it on a screen. The light is diffracted with the passage of the slits and product on the screen of the fringes of Interférence, i.e. an alternation of enlightened and not-enlightened bands. Young from of deduced the undulatory natural from the light (see also Duality wave-particle).
Young modulus
See also: Modulus Young
In Mechanical of the continuous mediums, Young left his name to the Young modulus, who characterizes the Elastic strain of a material according to the Contrainte which is applied to him. The higher the Young modulus is, the more the material is known as rigid.
Vision and theory of the color
Young is also regarded as the founder of physiological optics. In 1793 it explains how the eye adapts the Vision to various distances by modifying the curve of the Cristallin. In 1801 it is the first to describe the Astigmatisme. It presents in its conferences the assumption that the perception of the color is due to the presence on the retina of three receiving types of which react respectively to the red, the green and blue. This theory will be developed thereafter by Hermann von Helmholtz and will be checked in experiments in 1959.
Medicine
In Physiology, Young makes an important contribution in Hémodynamique at the time of the Croonian Lecture of 1808 with his talk on the Fonctions of the heart and the arteries . Among his writings one finds also his Introduction to the medical literature , which presents a practical Système of Nosologie (1813) and a practical and historical Traité on the Tuberculose (called at the time " consumptive disease") (1815).
Linguistics
Young compared the grammar and the vocabulary of 400 different languages. In 1813 it introduces the term of Indo-European Langues.
Hiéroglyphes
Young is in addition one of the first to decipher some Hiéroglyphe S. In 1814 it finished the translation of the text Démotique of the Pierre de Rosette, and a few years made later of progress in the comprehension of the hieroglyphic alphabet. In 1823 it publishes a Compte-rendu of recent discovered on the hieroglyphic writing and the Egyptian Antiquité . It takes again some of its conclusions in the famous article Egypt which it writes for the edition 1818 of the Encyclopædia Britannica.
When Jean-François Champollion publishes his complete translation of the hiéroglyphes, Young recognizes his projection but asks him at the same time to state to be itself supported on its former articles. Champollion, which arrived at the fundamental comprehension of the hieroglyphic system thanks to its control of the Copte, refuses to admit any paternity of the translation with Young, whose interpretations comprised lacks and errors. A schism follows, during which the British support Young and the French maintain that Champollion is the single scanner of the hiéroglyphes. In spite of this quarrel strongly nourished by the political tensions of the time, Champollion will let Young later reach manuscripts demotic with the Louvre when it is preserving.
Sources
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article of the English wikipédia
- Simon Singh, History of the secret codes. From Egypt of the Pharaons to the quantum computer , Slats, Paris, 1999. ;
- Andrew Robinson, Thomas Young: The last man who knew everything , pi Near, 2006.