Elements of surveying and levelling; with descriptions of the instruments and the necessary tables (1870)
Davies, Charles, 1798-1876 · New York and Chicago, A. S. Barnes & Company · leaf 87
e. Applications to Heights axd Distaxces. I. To determine the horizontal distance to a point which is inaccess-ible by reason of an intervening river.* 43. Let C be the point. Measurealong the bank of the riyer a hori-zontal base-line AB, and select thestations A and B, in such a mannerthat each… … SEC. I.] HEIGHTS AND DISTANCES. 85 Let us suppose that we have measured AB = 600 yards;CAB = A = 5r 35, and CBA = B = 64:° 51.Then, C = 180° - (A + B) = 57° 34. To find the distance BC sin C : sin A : : AB : BC.Applying logarithms, we have, (a. c.) log sin G (57° 34) 0.073649 log sin A (57° 35)…
Surveying
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