The theory and practice of surveying. Designed for the use of surveyors and engineers generally, but especially for the use of students in engineering (1886)
Johnson, J. B. (John Butler), 1850-1902 · New York, J. Wiley & sons · leaf 468
he targets wereusually elevated from 5 to 30 feet higher. The excessive heights of the stations from Chicago toBuffalo are due to the country being very heavily timbered,and the surface only gently rolling. In the vicinity of LakeSuperior they averaged only about 35 feet high, while fromBuffalo to… … SCAFFOLD OBSERVING TRIPOD Fig. 120. erected, one for carrying the instrument and one for sustain-ing the platform on which the observer stands. These shouldhave no rigid connection with each other. These structures areshown in plan and elevation in Figs. 120 and 121. The innerstation is a tripod on…
Surveying
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