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 84
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 … Dem. For the angle bac is meafured by half the femicircular arc bec,which is- equal to 180 degrees. (211) And Z. dac is meafured by half the arc dec, greater than 1800.Alfo z, eac is meafured by half the arc ec, lefs than 1800.Therefore thefe angles are refpe&ively equal to, greater, or lefs…
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-145-81.webp)