Page:The New International Encyclopædia 1st ed. v. 06.djvu/723

* ECLIPTIC. 6S1 ECOLE DES BEAUX-ABTS. ECLIPTIC ( Lat. ec/ip'tcus, from Gk-ixXfiir-rwof, fklcilitikox, reUiliiig to all oclipsi-, from tKXiii/tf eklciiisis, eclipse). The uiiuie given to the great circle of the heavens round which the sun seems to travel from west to east in the course of a year. It took its name from the early observed fact that eclipses (q.v.) happen only when the sun and moon are in or near this circle. At- tention about sunset or sunrise shows that the sun is constantly altering his jjosition among the stars visible near him, leaving them every day a little farther to the west; that this motion is not exactly east and west, or parallel to the celestial equator, becomes evident by obscring that the sun's height at midday is constantly altering. It was discovered very early in the history of astronomy that twice a year, about March lilst and September 23d. the sun is exact- ly on the enualor. The two points of the equator on which the sun then stands are the equinoctial points (see Equixoxes; Equixoctiai.), and are the intersections of the equator and ecliptic. Again, there are two days in the year on which the sun reaches its greatest and its least mid- day elevation in the Xorthern Hemisphere — the first is the 21st of June: the second, the 21st of December. On these days the sun has reached his iireate^t distance from the equator either ■way. and the points in his course where he thus sceins to pause or halt in his retreat from the equator are called the solstices {solis stationes) . These four points are distant from one another by a quadrant of the circle, or 90°. Each quad- rant is divided into three arcs of 30°, and thus the ecliptic is divided into twelve arcs of that length, called signs of the zodiac (q.v.). These arcs or signs have been named after constellations through which the ecliptic passes. As the equi- noctial points are not fixed, but recede yearly westward about 50", and in the century about 1° 24', the same constellations and signs that coincided when the division of the ecliptic took place no longer coincide. The constellation of the Ram, for instance, which originally stood in the first arc or sign, now stands in the second. every constellation having advanced forward 30°, or a whole sign. Jfodem astronomers therefore pay little attention to these constellations and signs, but count celestial longitudes from the existing spring equinoctial point from 0° to 360°. Not only do the points change where the ecliptic and equator cross each other, but the angle be- tween these two circles, called the obliquity of the ecliptic, is also variable. It is at present nearly 23. .5°, and is diminishing at the rate of about .50" in a century. Were it to go on di- minishing always, the ecliptic and the equator would at last coincide. The decrease, however, has a limit: the obliquity oscillates between two definite bounds, which it can never pass. It has been calculnted that the diminution will continue for about 1.50 centuries, when the obli- quity will only amount to 22.25°. .fter that it will again increase, tending toward an upper limit of about 25°. These slight alterations cannot sensibly aiTect the seasons. The physical cause of this change of the ob- liquity is the gravitational action of the other planets, especially .Tnpiter. Mars, and Venus, on the mass of the earth. The fact of the change was known to astronomers in verv- ancient times: Herodotus mentions an old tradition of the EgjTJtiana that the ecliptic had formerly been peqiendicular to the equator — a notion into which they were most probably led by observing for a long series of years that its obliquity was constantly diminishing. Though it was not until after the discovcrj- of the law of gravita- tion that the change of the obliquity could be explained, yet that it was changing was long believed by many astronomers, although some doubted whether the difl'erences in the values at diflerent times were not due to errors of obser- vation. The earliest known measure of the ob- liquity of the ecliptic was probably made in China. ECLOGITE (from Gk. ^Koyos. cklogos, se- lected, from fK^yeiv, ekleyein, to select, from </t, ck, out + X^eiv, legein, to gather). A variety of crystalline rocks, remarkable for its composi- tion and great beauty. It has a ground mass of pale-green pyroxene and hornblende, in which reddish crystals of garnet and blue crystals of cyanite are included. The rock is of rare occur- rence, being found only in a few regions where Arch«an gneisses and "schists are exposed. The type locality for eclogite is the Bavarian Fich- telgebirge. ECLOGUE (Lat. ecloga, Gk. £(to7^, ekloge, selection, from ixXiydv, eklegein, to select). A pastoral poem, in which are related the loves and adventures of shepherds and shepherdesses in some ideal scene and period. This kind of poetry flourished among the ancients. Theocritus and Vergil being well-kno%Tii examples. Under the name of pastorals, eclogues were fashionable in the sixteenth century. A good English speci- men is Spenser's Shepherd's Calendar. They were revived in the eighteenth century by Am- brose Philips and Pope, "but are no longer written. The term, however, is still applied to poems de- scriptive of country life and scenes. For the recent treatment of' the eclogue, consult Bridges. "New Poems," in Poetical TTorfcs (London, 1S99). See Pastob.vl Poetry. EC'NOMITS. A hill near Licata. Sicily, which gave its name to the famous naval battle in which Regulus in B.C. 256 vanquished the Car- thaginians. ECOLE DES BEATJX-AKTS, S'kftl' di b6'- zUr' ( properly Ecole X.Tiox.ii: et Spficnu: DES BE.t:.x-ABTs") . The national school of the fine arts in France, probably the most important institution of the kind in the world. It was founded in 1648, coineidently with the Academic Royale de Pein- ture et de Sculpture, as the academic school where each professor in turn gave instruction in drawing. It did not receive its official title until 1793. Since then the only changes have been in the form of its administration. In 1815 the Academic, des Beaux-Arts was given its present name, and in 1863 the outside ateliers, which arc practically workshops, were added to the main Ecole. The Academy judges the yearly competition for the Prix de Rome (q.v.). directs the Academy at Rome, and has charge of the Ecole- generally. The Academy of .rchitecture was annexed to the .cademy of Painting and Sculpture in 1071, with Francois Blondel as its first professor, and was incorporated into the Academic des Beaux-Arts in 1793. The School of .rchitecture is now one of the most impor- tant branches of the Ecole des Beaiix-.Xrts. In 16GG the Prix de Rome was instituted, and in