A treatise on surveying ; in which the theory and practice are fully explained (1860)
Alsop, Samuel · Philadelphia, E. C. & J. Biddle & co. · leaf 106
et up a stake at E, in the line of sight: then theprolongation of the line BA bisects EAC. Let FG (Fig. 67) be thehorizontal axis. Then, ifthe line of collimationmakes the angle FAB cacute, when the telescopeis turned over it will makeFAC = FAB. The angleCAD is therefore equal totwice the error.… … G F 104 PLANE TRIGONOMETRY. [Chap. III. Hence, to rectify the error, the instrument being in thesecond position, place a stake at H, one fourth of the dis-tance from E to C, (Fig. 67,) and, by means of the screwsa, a, (Fig. 51,) move the diaphragm horizontally till thevertical line passes through…
Surveying
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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-400-277.webp)
