420 EXPLANATION OF THE PRINCIPAL TERMS

Dominical Letter, one of the first seven letters ofthe alphabet, which is usually marked in red, and em-ployed in the Almanack for distinguishing the Sundaysthroughout the year.

Draco, or the Dragon, a northern constellation con-sisting of forty-nine stars.

Dragon’s Head, or the Ascending Node, is the north-ern intersection of the moon’s orbit with the ecliptic,which is marked thus LZ.

Dragon’s Tail, or the Descending Node, is the south-ern intersection of the moon’s orbit with the ecliptic,which is marked thus N.

E.

Earth, the globe which we inhabit; one of the sevenplanets, and the third in order from the fun.

Eccentricity, the distance between the center of anellipsis and either of its foci.

Eclipse of the fun, an obstruction of his light, occasionedby the interposition of the dark body of the moon be-tween him and our sight.

Eclipse of the moon, a deprivation of her light, occa-sioned by the interposition of the earth between the funand moon.

Ecliptic, a great circle of the sphere, in which the funalways appears to move; so called, because eclipses ge-nerally happen when the moon is in or near this circle.The obliquity of the ecliptic is the angle it makes withthe equator, which is now about 23 degrees 28 minutes.

Elevation of the Pole, is an arc of the meridian con-tained between the pole and the horizon; which isal ways equal to the latitude of the place, or the distanceof the zenith from the equator.

Elonga-

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