Light; a course of experimental optics, chiefly with the lantern . y for each colour, supposing only we find onexperiment that such a combination of colours will composewhite light. 43. Each Colour has its own Angle of Total Re-flection.—Newton proved the special refrangibility of eachcolour by another still more beautiful experiment; one of themost elegant ever devised. It depends on the facts alreadynoticed, that the angle of total reflection must vary with theindex of refraction (§ 32); the violet rays being totallyreflected (because more refracted), at an angle which wouldallow the red ray
Light; a course of experimental optics, chiefly with the lantern . y for each colour, supposing only we find onexperiment that such a combination of colours will composewhite light. 43. Each Colour has its own Angle of Total Re-flection.—Newton proved the special refrangibility of eachcolour by another still more beautiful experiment; one of themost elegant ever devised. It depends on the facts alreadynoticed, that the angle of total reflection must vary with theindex of refraction (§ 32); the violet rays being totallyreflected (because more refracted), at an angle which wouldallow the red rays to leave the denser medium. Newtontherefore arranged an experiment as in Fig. 50, except that F 2 LIGHT. [CHAP. he employed the parallel rays of the sun instead of thosefrom the lime-light lantern. A perpendicular slit n is placedin the optical stage with the objective removed, or on thenozzle of the lantern if an adjustable sUt is at command,(see Fig. 50, which shows all the arrangements in plan).As close to the slit as convenient, on a table-stand, simply. Fig. 50.—Newtons Experiment. Stood up on their ends, are two similar right-angled glassreflecting prisms, p and P2, with their reflecting sidestogether, kept together by an elastic band passed round neareach end; they must not, however, quite touch, and may,if necessary, bekept apart by a narrow slip of paper at eachend between them. In the direct path of the rays from theslit, is a focusing lens, f, and beyond that, on another TV.] NEWTONS EXPERIMENT. 69 table-stand, is placed a bisulphide prism-bottle, b, in theusual position for throwing a spectrum on the screen, s the path of the rays totally reflected from the film of airbetween p and P2, is another focusing lens, f, and beyondthat, on a third table-stand, a second bisulphide prism-bottle,B2, which throws its spectrum on the screen, ss, adjusted atright angles to the other screen. All being thus arrangedin the general, the double prisms, p and P2, can be tu
Size: 1542px × 1621px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookidcu3192403121, bookyear1882
