Austin, Louis W. (Louis Winslow), 1867-1932, Thwing, Charles B. (Charles Burton), 1860-1946, joint author · Boston, Allyn and Bacon · leaf 121
he ray of lightis received through acollimator, (7, which con-sists of a tube providedwith a slit and lens, andfixed to point exactlytoward the centre of agraduated circle, uponwhich rotates the ob-serving telescope T,which also points to thecentre of the circle.The telescope may beclamped in any… … Fig. 55. LIGHT. 109 The Circular Vernier — The vernier employed in read-ing angular divisions is identical in principle with thestraight vernier already described. Since there is no uni-form practice in regard to the number of divisions employedin circular verniers, the student should first notice…
Physics
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