A treatise on levelling, topography, and higher surveying (1876)
Gillespie, W. M. (William Mitchell), 1816-1868, Staley, Cady, b. 1840, ed · New York, D. Appleton and company · leaf 142
at 63° 26, and then proceed as before. The objectswill be seen to coincide when at some point D. ThenAD^JAB. If the index be set at 71° 34, then the meas-ured distance will be -JAB, and so on. THE PRACTICE. 123 If the index be set at the complements of the above angles,the distance measured will… … the line to E, where the objects are seen to coincide with eachother; then is AE twice AB, and hence ED = AE. Fig. 156
Surveying
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