583
INDEX.
N. B. The Numbers are those of the Articles as they slaiul on the Margin.
Bight. Aberration, of Light , 10. Spherical, for reflected rays, 128.
Circle of least, 154.156. Of a system of surfaces for refractedrays, 281. 291. Of a thin single lens, 293. Its comparativeamount in different lenses, 307. Of lenses generally, 297. Ofa system of thin lenses, 308. Its effect in lengthening orshortening focus, 289. General equations for its destruction,312,313.
Aberration, Chromatic , explained, 456. Circle of least, 457.Principles of its destruction, 459.
Absorption of Light by uncrystallized media, 484, et seq.; bycrystallized, 1059, et seq.
..JL.. Aehromaticity, general conditions of, 459.
* Achromatic refraction, 427. 448. Its general conditions, 459. At
common surface of two media, 478. Produced by combina-tions of one medium, 451.
1 Achromatic Telescope, theory of, 456, et seq*
Adaptation of the eye to different foci, 356.
Amethyst, its peculiar structure , 1044.
Amici, his prismatic telescope, 453, His microscopes, 1145.
Amplitude of an undulation, 605.
Analcime , peculiar polarisation produced by, 11 S3.
Analysis of solar light by the prism, 397. 406. By colouredglasses. 506. Of tl.o cvU> ura of itiia plates, 644.
Angle of polarization, 831.
Apertures , waves transmitted through, * 631. Phenomena ofdiffraction through, 729. Of telescopes, of different forms,their effect, 768.
Apophyllite, peculiar rings exhibited by its several varieties, 915.918. Biaxal, 1130. Variety called Tesselite, its structure,1130, 1131.
Amaco, M ,hia mode of measuring refractive indices, 739. Hislaw of polarization by oblique transmission, 947. His disco-very of the rotatory phenomena in quartz, 1037. His laws ofinterference of polarized rays, 947.
Axes defined, 783. Optic, 889. Differ for differently colouredrays, 921. Their situations calculated a priori, 1008.
Axes of elasticity, 1000. Polarizing, Brewster’s theory of theircomposition and resolution, 1020. Of double refraction, 781.Positive and negative, 1021. 1032.
Biot, M., his doctrine of movable polarization, 928. Hisapparatus described, 929. His researches on the rotatoryphenomena,- 1037. 1045. IIis law of the isochromatic linesin biaxal crystals, 907. His rule for determining the planes ofpolarization within biaxal crystals, 1070.
Blair, Dr., his achromatic telescopes with fluid object glasses,474.
Blindness, its causes and remedies, 360.
Bow, coloured prismatic, 555, 556.
Brewster, Dr., his law of polarization by reflection, 831.Laws of polarization by oblique transmission, 866. Hisoptical researches and discoveries, passim* His theory ofpolarizing axes, 1020.
Brightness, intrinsic and absolute, 29. See Photometry. OfImages, 349.
Calorific ray» of the solar spectrum, 1147.
Camera obscurm, 330.
Cassia, oil of, its remarkable refractive and dispersive powers,1117. 1121. Experiment upon, 1122.
Catacaustics, or Caustics by reflexion, 134, et seq. Their length,144. Determination of from a given reflecting curve, 137.Conjugate, J46. Density of rays in, 160.
Caustics by refraction, 226, et seq. Of a plane, 238.
Chaulnes, Due de, phenomena observed by him, 687.
Chemical rays of the spectrum, 1146 , el seq.
Chromatics, 395. Chromatic aberration. See Aberration.Chxular polarization, 1037, et seq. Vibrations, 627.
Clairaut , his condition for construction of achromatic objectglasses, 467.
Coloured rays unequally absorbed by media, 486.
Coloured rings awl fringes. See Rings and Fringes.
Colours of natural bodies not inherent, 410. Newton ’s theoryof such colours, 113 4, et seq. Of the prismatic spectrum, 424.Of flames, 521. Of thin plates, 633. Of thick plates, 676.Of mixed plates, 696. Of fibres and striated surfaces, 700.
Colours, primary, Mayer’s hypothesis respecting, 509. Young’s,518.
Colours polarized by crystallized plates, 884.
Colours, periodical, 635, ot seq. True and false, 1143.
Composition and resolution of vibrations, 620. Of axes, 1020.
Cord, stretched, analogy between its vibrations and those of theether, 977. 980. 986.
Cornea of the eye, 350. Case of malconformation of, remedied,358, 359.
Crack in a heated glass plate, its effect on the polarized tints,
1102 .
Crested fringes observed by Grimaldi, 728.
Cross, black, traversing the polarized rings. Its form in uniaxalcrystals, 911. In biaxal, 1092.
Crystals, IJniaxal, enumerated, 785. 1124. Law of doublerefraction in, 795. Biaxal, table of the inclinations of theiraxes, 1124. Phenomena of the polarized lemniscates ex-hibited by, 892, et seq . 1069, et seq. General law of doublerefraction in, 1011, et seq. Action of heat on, 1109. Positiveand negative, or attractive and repulsive, 803. 942. Dow dis-tinguished, 915.
Crystallized surfaces, their action on reflected light, 1123.
Crystalline of the eye, 352.
Deflexion oflight. Newton ’s doctrine of, 713.
Depolarization of light, 925.
Depolarizing axes, 1087.
Deviation of a ray after any refraction in one plane, 211. Mini-mum produced by a prism, 216. Of tints from Newton ’s scalein the polarized rings, 915. 1125.
Diacaustics. See Caustics by refraction.
Dichroism , phenomena of, in uniaxal crystals, 1064. In biaxal,1067. Expressed by an empirical formula, 1073.
Dichromatic media, 499.
Diffraction oflight, 706, etseq.
Dilatation of rings at oblique incidences, 639. 669. Of thediffracted fringes by approach of the radiant point, 711. Ofglass, its effect in imparting the polarizing property, 1089. Ofjellies, 1094.
Discs, spurious, of stars, 767.
Dispersion of light, 395, &c.
Dispersive powers of media, 425. Methods of determining them,428.431, 435. A very precise practical one for object glasses,483- Table of, 1120. Of higher orders, 446.
Due de Chaulnes, his experiment on coloured rings, 687.
Elastic forces of a medium generally expressed, 998.
Elasticity , ; axes of, 1000. Surface of, 1004-
Elliptic, vibrations of ethereal molecules, 621.
Emanation , oblique, law of, 43.
Ether, its vibrations the (hypothetical) cause of light, 563.Frequency of its pulsations, 575. See Undulations .
Extinction of light, 484. 1138.
Eye , its structure, 350. Change of focus, 356. Of fishes, 368.See Vision.
Films, interrupting, in crystals, phenomena exhibited by, 1078,et seq .
Fits of easy reflexion and transmission, 526. 651
Fixed lines in the spectrum described, 418. Their utility inoptical determinations, 420.
Flames, coloured,their phenomena, 520.
Foci, general determination for any curve by reflected rays, 109.112. In a sphere, 123. 250. Conjugate, 126. General inves-