Light; a course of experimental optics, chiefly with the lantern . Fig. 139.—Reflected Rod. projected pretty accurately, it is reflected from the water, as inFig. 139, as boys play ducks and drakes, or as a shotricochets on the surface of the sea.^ Now let a (Fig. 139). Fig. 140.—Refracted Rod. be the wave-lengths in a ray of light, the rod r will repre-sent those vibrations which reach the retarding medium ^ The rods must strike the surface of the water at a considerably less•angle than in Fig. 139. 222 LIGHT. [chap. as at B j and they are reflected to c. Lay next a rod verticallyon the face
Light; a course of experimental optics, chiefly with the lantern . Fig. 139.—Reflected Rod. projected pretty accurately, it is reflected from the water, as inFig. 139, as boys play ducks and drakes, or as a shotricochets on the surface of the sea.^ Now let a (Fig. 139). Fig. 140.—Refracted Rod. be the wave-lengths in a ray of light, the rod r will repre-sent those vibrations which reach the retarding medium ^ The rods must strike the surface of the water at a considerably less•angle than in Fig. 139. 222 LIGHT. [chap. as at B j and they are reflected to c. Lay next a rod verticallyon the face of the catapult, so that the end strikes the surfaceof the water first, as at e (Fig. 140). Such a rod re-presents mechanically the vibration at right angles to theformer; and it will be found it is no longer reflected, butswung round in some such direction as F. But this is not all; for attentive observation, even withthis rough and simple apparatus, will soon show that, in rodsplaced in intermediate positions, there is a sensible, visibletendency on meeting the water to swing round into one orother of the two positions we have examined. It followsthat if we could project such a rod, without losing itsenergy, against surface after surface, it would graduall
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Keywords: ., bookcentury1800, bookdecade1880, bookidcu3192403121, bookyear1882
