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
efs than 90:es. 1 214. Corol. Hence in a right angled triangle (bac); the angularpoint (a) of the right angle, and the ends (b, c) of the oppofite fide, areequally diftant from (f) the middle of that fide; that is, a circle will al-ways pafe thro the right angle and the ends of its oppofite fide… … Dem. Draw the diameter cf ; then Z. acf is right. (209) Therefore the Z. acf is meafured by half the arc cdf. (107) But the angle dcf is meafured by half the arc df. (211)Therefore Z. acd (=z. acf—z.dcf) is meafured by half the arc DC (=CDF — DF). And z. c e d is meafured by half the arc c D» (211)…
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-24-10.webp)
