A treatise on surveying, comprising the theory and the practice (1906)
Gillespie, William Mitchell, 1816-1868, Staley, Cady, 1840- · New York D. Appleton · leaf 255
ings on the micrometer head indicate an elevation of the eye endof the telescope. There is a cam hook, J/, between the two platesvi^hich enables the observer to raise the upper part of the super-structure off the micrometer screw, and which is kept in positionby means of a spring, ;S, while…
Surveying
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
