Austin, Louis W. (Louis Winslow), 1867-1932, Thwing, Charles B. (Charles Burton), 1860-1946, joint author · Boston, Allyn and Bacon · leaf 29
nsultSteward & Gee. THE CATHETOMETER. The cathetometer (Fig. 7) isan instrument for measuring ver-tical distances less than a metre.It consists of a heavy vertical bar,_B, upon which is ruled a scale.This bar is supported upon atripod provided with levellingscrews, and is capable of rotation… … Fig. 7. MEASUREMENT OF EXTENSION. 17 The following adjustments are necessary: — 1. The intersection of the cross-hairs in the eyepiecemust be in the line of collimation of the telescope. To makethis adjustment, set the telescope upon a dot so that thepoint of intersection of the cross-hairs appears…
Physics
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