Lockyer, Norman, Sir, 1836-1920, Seabroke, G. M. (George Mitchell), 1848-1918 · London, Macmillan and co. · leaf 58
S AND PTOLEMY. 35 not been unaccompanied by changes of religious ideasand observances in origin connected with the stars. We now come to Ptolemy. There was another instru-ment used by Ptolemy, and described by him, which wemay mention here; it was called the Parallactic Rules,so named perhaps… … Fk;. 14.—Instrument for Measurini< Altitudes. tlie third, which had divisions on it, made the one at thebase, or was the chord of the angle at the summit. Oneof the equal sides, D F, was furnished with j)ointers, overwhich a person observed the star, whilst the other, d e,was placed vertically,…
Astronomy · Telescopes
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