Davies, Charles, 1798-1876 · New York, Cincinnati [etc.] American book company · leaf 62
et OAbe the line to be prolonged.Lay off OAB = 120°, orCAB = 60. Measure AB,of such length as to permitBC to be measured withoutmeeting the obstruction.Make ABC = 60°, andmeasure BC, equal to AB.If ^ be not in sight from C, make the angle BCP equal to 120°, and resume the survey ofthe line. AC is… … 56 ELEMEISTS OF SURVEYIH^G. [book II.
Surveying
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