《Tetrabiblos》Number Of The Modes Of ProrogationClaudius Ptolemy（Ashmand 英譯 1822）
87.) In the Appendix will be found a plate, containing diagrams drawn by the instruments in question, which, though not completely filled up, will show how easily, and, at the same time, how accurately, the measure of time in directions may be ascertained.
段落 tetra-3-numberofth-72public-domain (Ashmand 1822)
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