Elements of natural philosophy (Volume 2-3) (1850)
Bartlett, W. H. C. (William Holms Chambers), 1804-1893 · New York : Barnes · leaf 316
ass, the focal distance usualof the first being to that of the second as 33 to 50,com ina lon;these numbers expressing the relative dispersive pow-ers as determined by experiment; (see Table §116). Theconvex lens should have the greater power, and, there-fore, be constructed of the crown-glass;… … Illustration ; To illustrate : let parallel rays be received by the lensA ; its action alone would be, to spread the differentcolors over the space VE, whose central point m, is dis-tant from A, 33 units of measure, (say inches), the violetbeing at V, and the red at R\ the action of the lens…
Mechanics · Acoustics · Optics
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