A new manual of the elements of astronomy, descriptive and mathematical .. (1868)
Kiddle, Henry, 1824-1891 · New York, Ivison, Phinney, Blakeman & co.; Chicago, S.C. Griggs & co. · leaf 82
EARTH AT THE SOLSTICE. TWILIGHT. 77 a. When the sun is in eitherof the equinoxes, one half of itwould constantly appear above thehorizon of a place at either of thepoles, except for refraction, theeffect of which is very great atthose points; so that the sun, atthe equinox, appears wholly abovethe… … TWILIGHT. 117. When the sun is a short distance below the horizon,its rays fall on the upper portions of the atmosphere, whichlike a mirror reflect them upon the earth, and thus producethat faint light called twilight The morning twilight isgenerally called the dawn. Fig. 51.H
Astronomy
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