Electro astronomical atlas ... with explanatory notes, questions and answers (1874)
Spoor, J. W. (Joseph W.) · Albany, N.Y., Weed, Parsons and Company · leaf 62
on its axisalways uniform and invariable ? A. Its revolution is invariably the same, once intwenty-four hours. Q. What advantage is derived from this regu-larity of the Earths motion ? A. We obtain by this the only true principleof reckoning time in hours, days, etc. Remark.— 1st. While all the… … ELECTRO-ASTRONOMICAL ATLAS. 87 2d. The different periods of time in common useall date from this. Weeks, months and years arerecorded by days and fractions of a day ; whilehours, minutes and seconds are divisions andsubdivisions of the day. Q. How may we illustrate the plane of theEcliptic ? A. By…
Astronomy
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