The description and use of the sector, crosse-staffe, and other instruments : with a canon of artificiall Sines and Tangents, and the use thereof in astronomie, navigation, dialling and fortification .. (1636)
Gunter, Edmund, 1581-1626 · London : Printed by William Iones for Iames Bowler · leaf 385
houre-lines, wee are to confider, fii ft the length of theaxis of the ftyle in inches and parts of inches; Secondly theheight of the ftyle aboue the plane; thirdly the angles at thepole betwecne the proper meridian and the houre-circles*Thcfe being knowne, will help vs to find, firft the angle… … Let the triangle AB C be made equall to the flyle belong-ing to your plane, A C the fubftylar,5 C the axis of the % le,ABthe length of the ftyle perpendicular to the plane. Theohauing drawnethc line B D perpendicular to the axis on thecenter B, and any femidiameter B D defcribe an occult arke ofa…
Astronomy · Puritans
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