The elements of theoretical and descriptive astronomy, for the use of colleges and academies (1872)
White, Charles J. (Charles Joyce), 1839-1917 · Philadelphia, Claxton, Remsen & Haffelfinger · leaf 108
be perpendicular to theplane of the meridian: and second, its motion in that planemust be uniform. Both these conditions are so very nearlysatisfied by the motion of the vernal equinox, that any twosidareal days may be considered to be sensibly equal to eachother; but neither condition is satisfied… … 102 EQUATION OF TIME. causes of the inequality of the solar days, the effect of each ofwhich we will now proceed to examine. 107. Irregular Advance of the Sun in the Ecliptic.—Observa-tion showrs that the suns motion in longitude is not uniform.The mean daily motion is, of course, obtained by…
Astronomy
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