universal gas constant: see gas laws.

solar constant, the average amount of radiant energy received by the earth's atmosphere from the sun; its value is about 2 calories per min incident on each square centimeter of the upper atmosphere. The actual value of the energy varies with several factors; the most important factor is the earth's distance from the sun, which changes because of the earth's elliptical orbit. For computing the value of the solar constant, the astronomical unit, or average earth-sun distance, is used.

Troyon, Constant, 1810-65, French painter of the Barbizon school, famous for his pictures of animals, particularly cows, in landscape. Among his paintings are Oxen at Work (Louvre) and Holland Cattle and Road in the Woods (Metropolitan Mus.).

Rydberg constant, physical constant used in studies of the spectrum of a substance. Its value for hydrogen is 109,737.3 cm^-1.

Planck's constant, fundamental constant of the quantum theory. It is represented by the letter h and has a value of 6.63 × 10^-34 J-sec. The combination h/2π, denoted by h (called "h-bar"), occurs frequently.

Pierné, Henri Constant Gabriel, 1863-1937, French organist, conductor, and composer; pupil of Massenet and César Franck. His cantata Edith won the Prix de Rome in 1882. He succeeded Franck as organist at Ste Clotilde, 1890-98, and was chief conductor (1910-32) of the Colonne Concerts. He was elected to the Académie des Beaux-Arts in 1924. His most popular works are the oratorio La Croisade des Enfants (1905) and the piano piece Marche des petits soldats de plomb. He also wrote eight operas, instrumental and orchestral music, and songs.

Estournelles de Constant, Paul Henri Benjamin, baron d', 1852-1924, French diplomat and pacifist. He wrote and spoke tirelessly in favor of disarmament and international conciliation, was a delegate to the Hague peace conferences (1899 and 1907), and was awarded the 1909 Nobel Peace Prize jointly with Auguste Beernaert.

Coquelin, Benoǐt Constant, 1841-1909, French actor, known as Coquelin aǐné [the elder]. He made his debut at the Comédie française in 1860 and achieved fame in classic comic roles, such as the valets in Molière's plays and Beaumarchais's Figaro. He made an extensive tour of Europe and America in 1886. In 1897 he created his greatest characterization, the title role in Rostand's Cyrano de Bergerac, at the Théâtre de la Porte-Saint-Martin, which he also managed. In 1900 he toured the United States with Sarah Bernhardt and returned to Paris to play opposite her in Rostand's L'Aiglon. Highly critical and analytical toward his art, and believing in simulated rather than real emotions, he wrote L'Art et le comédien (1880) and Les Comédiens, par un comédien (1882); his approach led to an interesting debate with Sir Henry Irving on techniques of acting. His brother, Ernest Alexandre Honoré Coquelin, 1848-1909, known as Coquelin cadet [the younger], acted at the Comédie française after 1868. At his best in secondary comic roles, he was also popular for his monologues and several amusing books written under the pseudonym Pirouette.

Constant, Paul Henri Benjamin, baron d'Estournelles de: see Estournelles de Constant.

Constant, Benjamin (Henri Benjamin Constant de Rebecque), 1767-1830, French-Swiss political writer and novelist, b. Lausanne. His affair (1794-1811) with Germaine de Staël turned him to political interests. He accompanied her to Paris in 1795 and served (1799-1801) as a tribune under the first consul, Napoleon. When Mme de Stäel was expelled (1802), however, he went into exile with her, spending the following 12 years in Switzerland and Germany. In 1813 he published a pamphlet attacking Napoleon and urging constitutional government and civil liberties. On Napoleon's return from Elba, however, Constant accepted office under him. After Napoleon's final defeat at Waterloo and the restoration of the Bourbons, Constant continued his political pamphleteering, calling for a constitutional monarchy. He served (1819-22, 1824-30) in the chamber of deputies. Constant gained a great reputation as a liberal publicist, and his funeral (shortly after the July Revolution, 1830, which he had supported) was the occasion for great demonstrations. His most important work, the introspective and semiautobiographical novel, Adolphe (1816, tr. 1959), is highly regarded for its style. Parts of his correspondence and journals have been published, the latter as Le Journal intime (1887-89) and Le Cahier rouge [the red notebook] (1907). The discovery of an unfinished novel, Cécile (1951; tr. 1953), has contributed to a new appreciation of Constant's literary merit.

Constant de Rebecque, Henri Benjamin: see Constant, Benjamin.

Benjamin Constant, Paul Henri: see Estournelles de Constant.

Apparent displacement of a star or other celestial body resulting from Earth's orbital motion around the Sun. The maximum displacement is about 20.49 seconds of arc. It depends on the ratio of Earth's orbital speed to the speed of light and Earth's direction of motion and thus provides confirmation that Earth orbits the Sun rather than the reverse.

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(born Oct. 25, 1767, Lausanne, Switz.—died Dec. 8, 1830, Paris, France) French-Swiss novelist and political writer. He had a tumultuous 12-year relationship with Germaine de Staël, whose views influenced him to support the French Revolution and subsequently to oppose Napoleon, for which he was exiled (1803–14). He later served in the Chamber of Deputies (1819–30). Adolphe (1816) was a forerunner of the modern psychological novel. Among his other works are the long historical analysis of religious feeling De la Religion, 5 vol. (1824–31) and his revealing journals (first complete publication, 1952).

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