A treatise on surveying, comprising the theory and the practice ; (1887)
Gillespie, W. M. (William Mitchell), 1816-1868, Staley, Cady, 1840- [from old catalog] ed · New York, D. Appleton and company · leaf 411
BB cos. J (A - A + 0) 589. Leveling by the Horizon of the Sea. Owing to refraction,the apparent zenith-distance will be Z B A. Let R, = radius of the earth ; HH = horizon. E Then R + B B = cos. 0 26 396 LEVELING. _.BB,=Ra-co^_c)> cos. C L J Now, (1 — cos. C) = 2 sin.2 £ C. Transposing, we have… … = cos.2 JC — sin.2 J C. Substituting these values in equation (1). we get B B E(2sin.2i-C) = 2E sin.2|C cos.2 $ C - sin.2 fC cos.2 i 0 - sin.2 J C(Developing by the binomial formula)— = 2Ktan.2|-C (1 + tan.2 J- C - tan.^C +, etc.)Using the first two terms of the series, we haveBB = 2E tan2£C (1 +…
Surveying
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