The elements of astronomy, physical and geometrical (1715)
Gregory, David, 1659-1708, Halley, Edmond, 1656-1742. Synopsis of the astronomy of comets, Adams, John, 1735-1826, former owner. BRL, Boston Public Library (John Adams Library) BRL · London : Printed for J. Nicholson ... and sold by J. Morphew ... · leaf 380
BookII. (?/ AsTRoNoM¥• 329 them will be the meafure of the duration of theTwilight, while the Sun defcribes the ParallelJP A. But becaufe (by hypothefis) it is theieaft Twilight, none of thefe arcs, befidesP^,will reach to C R. (For while the Sun defcribesin its Diurnal motion any other Parallel,…
Astronomy
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