The elements of navigation : containing the theory and practice, with all the necessary tables, to which is added, a treatise of marine fortification ... (1754)
Robertson, J. (John), 1712-1776, Adams, Charles Francis, 1807-1886, former owner. BRL, Adams, John, 1735-1826, former owner. BRL, Boston Public Library) John Adams Library BRL · London : Printed for J. Nourse ... · leaf 83
(hewn, that the angle bce is equal to twice the angle bae. Confequently the angle bcd (=Z_ bce -f- L. Ecd) is equal to twice the angle bad (=£ bae -\-C ead). (j38) 211. Corol. I. Hence an angle (bad) at the circumference is meafuredby half the arc (bd) on which it ftands. For the angle at the… … 213. GEOMETRY.ai3. THEOREM XVII. r An angle (bac) in a femicircle, is a right one. An angle (dac) in a fegment lefs than a femicircle, b(is obtufe. An angle (eac) in a fegment greater than a femicir-thy is acute. H
Navigation · Nautical astronomy · Fortification
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![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-186-102.webp)
