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 113
t B, and mayitself revolve in the outer socket attached to the levelling-head.Either or both of these connections may be made rigid bymeans of proper clamping devices. If the horizontal limb Bbe clamped rigidly to the levelling-head and the alidade spindlebe allowed to revolve, then horizontal… … Fig. 17. ADJUSTMENT, USE, AND CARE OF INSTRUMENTS. 85 when the telescope is on the meridian, then for any otherpointing of the telescope the reading of this same verniergives the true azimuth of the line. It is necessary, therefore,to have two independent movements of telescope and horizon-tal limb…
Surveying
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
