ECLIPSE. The shadow which an opaque body throws on another body, on passing be tween it and a centre of illumination ; conse quently the moon, in its orbit round the earth, falls within the shadow of the earth, and suf fers an eclipse; the earth also falls within the shadow of the moon, and then the sun is ob scured or eclipsed. An eclipse does not, how ever, happen at every new or full moon, be cause the orbit of the moon is not exactly in the same level as the ecliptic, but the moons orbit inclines 6ve degrees nine minutes, con sequently the earth'a shadow commonly falls to the north or south of the moon, as it may be; and so it is with the shadow of the 111001I in regard to the earth, while that shadow is so small that it never covets but a small portion of the earth. Eclipses, therefore, only take place when the new or full moon happens near the time at which the moon in her orbit is crossing the plane of the ecliptic, called her nodes, either in ascending or descending, and these times are indicated in the almanac. The
angle under which the moon appears to the earth, is 31! but that of the earth to the moon in I lg 8ll. The length of the earth's shadow is four times the distance of the moon from the earth; but the shadow of the moon scarcely reaches the earth's centre, and there fore is very small at the surface; whereas that of the earth is 2 3-4 greater than the di ameter of the moon ; but to suffer an eclipse, the moon must be within 13 degrees of her node. The sun cannot be totally eclipsed more than eight minutes. Asa mere shadow, it is obvious that eclipses have no power or signification, good or bad.