Hall, Edwin Herbert, 1855-1938 · New York, H. Holt and company · leaf 126
ror draw an arrow 6 cm. long,marking the ends and the middle asin Fig. 76. Then place the smallblock so that the vertical pencil-markwhich it carries will point straightdown at point No. 1. With the straight-edged ruler drawtwo lines, well apart, toward theimage of this vertical line as seen inthe… … 2 >»>^>- Fig. 76. 114 PHYSICS. Then clear the paper and prolong each pair of lines till it conies toa crossing-point. The three points thus found will locate the imagesof object-points No. 1, Noi 2, and No. 3, respectively, and a line con-necting these three image-points will give an idea…
Physics
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