《Tetrabiblos》The Periodical Divisions Of TimeClaudius Ptolemy（Ashmand 英譯 1822）
But in other parts of the earth, where the pole of the equator is in the zenith, the fixed stars can never set nor rise; because the equator itself is then on the plane of the horizon, and circumscribes the two hemispheres (which it thus creates, one above and the other below the earth) in such a manner, that in one revolution every star must twice transit the meridian, some of them above, others below the earth.
段落 tetra-4-theperiodi-59public-domain (Ashmand 1822)
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