Merchant, F. W. (Francis Walter), 1855-1937, Chant, Clarence Augustus, 1865-1956 · Toronto : Copp Clark · leaf 307
the paper is held before a lamp the grease-spotappears brighter than the other portion, while if held behindthe lamp it appears darker. Now move the grease-spot screen between the two light-sources Zi, X2 (Fig. 327)-dt f\ rfi \ _ to be compared until it is equally bright allover its surface. Thenit… … Fig. 327.—The Bunsen grease-spot photometer. VERIFICATION OF THE LAW OF INVERSE SQUARES 297 lamp is the same. Henc . .i d^, d.^ are the distancea fxoiii thescreen of L^, Z.„ re^p:<;Lively, a8 befoff. 339, Jolys Di^iisioi) Photonieter. Two pieces of paraffinVfax, each about 1 inch scjuare and |…
Physics
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