Page 321 - Third Book of Reading Lessons

820 THIRD BOOK OF LESSON XX.
SOLAR SYSTEM •
MAG'NITUDE, n., comparative size or bulk. L. m nitudo, om mag­ nus, L., great.
PE'RIOD, n., a cycle or circle, in re rence to the revolution, or time of revolution, of one or more of the heavenly bodies. F. periode; G. 7Jeriodos,-peri, around, and hodos, a path or way.
Co 1ET, n., a star which appears suddenly, and as suddenly disap­ pear ,-so called from its hair-liJrn tail. F. com te; I. S. and L. co eta, om coma, L , the hair.
PLAN1ET, n., one of the celestial bodies in our system, which moves round and receives light from th Un. Planets are so called, be­ cause they change their places, and do not always keep the same distances with respect to one another, nor with the xed stars, as the xed stars do. F. plan te; S. and L. planeta, from planao, G., I stray or wander.
OR1BIT, n., the line described by the revolution of a planet; the path of a heavenly body. F. orbite, from orbis, L., a sphere or circle. TEL1ESCOPE, n., an optical instrument to enable the eye to see objects
a r o . F. telescope, from (G.) Lele, di tant, afar, and skopeo, I see,
I view.
P1u'sEs, n., appearances of the planetary bodies, as the changes of the moon. G. pha.es, om p aino, I show, I appear.
E'Qurnox, n., a period of the year, so called because then the night is equal to the day. F. equinoxe, om (L.) quus, equal, and nox, the night.
ELur'sES, n., ovals :-an ellipsis, in geometry, is a gure generated from the section of a cone ; in grammar, the omission of one or
more words in a sentence. G. elleipsis, om leipo, I leave out. EccEN1TRIC, a., out of the centre; deviating or wandering from the • centre. F. eccentrique, om (G.) ex, and kentron, a centre, a point. For " S ence," see p. 168; "Navigators," p. 30 ; "Solar," p. 122 ;
"Axis," p. 155; "Transit," p. 158; and"Atmosphere," p. 25.
1. THE science which determines the magnitudes, motions, distances, periods, and order of the heaven­ ly bodies, is called astronomy. It is so interesting ' and use l to mankind, that traces of it may be und in all the nations of the world. By its means, chronoJogists can compute the measure of time, navi­ gators direct their course through the trackless ocean, and geographers become acquainted with the gure and magnitude of the earth.
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