Page:Collier's New Encyclopedia v. 03.djvu/526

ECLIPSE 462 ECOLE POLYTECHNIQXJE side of her disk and ends on the western. The average number of eclipses in a year is four, two of the sun and two of the moon; and as the sun and moon are as long below the horizon of any particular place as they are above it, the average number of visible eclipses in a year is two, one of the sun and one of the moon. Total eclipses of the sun offer brief but intensely interesting phenomena for the astronomer's study. The nature of the sun's corona is as yet undetermined, and the aid of the spectroscope and of photog- raphy has not been sufficiently applied to the settling of the various problems presented. There were solar eclipses May 18, 1901, Aug. 30, 1905, Aug. 21, 1914, June 8, 1918, May 29, 1919. Lunar Eclipses. — An eclipse of the moon is an obscuration of the light of the formerly used to determine longitudes since they are the same viewed from all parts of the earth. The dates of a num- ber of important events of antiquity have been approximately determined by calculations concerning eclipses recorded at or near the time. Eclipses have been calculated up to the year 2161. ECOLE DES BEAUX ARTS (a-kol' da bo zar) (School of Fine Arts), the French Government school in Paris, founded by Mazarin in 1648, and pro- vided with an extensive staff of teachers. The competitions for the giands prix de Rome take place at this school. All artists between the age of 15 and 25, whether pupils of this school or not, may compete, after passing two preliminary examinations. The successful compet- -^n PiANE OF THE £CUPTfC <..' PLANE OF TMB ECUPT/t A. Eclipse of the moon ECLIPSE EARTH B. Eclipse of the sun moon occasioned by an interposition oi the earth between the sun and the moon; consequently, all eclipses of the moon happen at full moon ; for it is only when the moon is on that side of the earth which is turned away from the sun, and directly opposite, that it can come within the earth's shadow. Further, the moon must at that time be at the same time in the same plane as the earth's shadow; that is, the plane of the ecliptic in which the latter always moves. But as the moon's orbit makes an angle of more than 5° with the plane of the ecliptic, it frequently happens that, though the moon is in opposition, it does not come within the shadow of the earth. Planetary Eclipses. — The eclipse of a satellite takes place when the shadow of the primary obscures it. Jupiter offers the most favorable field for observation of this phenomenon. Such eclipses were itors receive an annual allowance from the state for three or four years, two of which must be passed at Rome. The school has about 2,000 students enrolled, and about 50 instructors. ECOLE POLYTECHNIQUE (pol-i- tek-nek') (Polytechnic School), a school in Paris established with the purpose of giving instruction in matters con- nected with the various branches of the public service, such as mines, roads and bridges, engineering, the army and the navy, government manufactures, etc. It was founded in 1794, and is under the direction of the Minister of War. Can- didates are admitted only by competitive examination, and have to pay for their board (about $200 a jrear). The pupils who pass satisfactory examinations at the end of their course are admitted to that branch of public service which they select.