INDEX. 237 



Page. 



Quartz, Airy's spirals seen in i:36 



rotatory polarization in 1J5 



Kainbow, explanation of, by De Domiuis Ill 



cause of its tints 113 



dimensions of 113-14 



Karefaction and condeusfttion, waves by 153 



Ray progress and wave progress in double refraction 2ii 



lietlectiou, angle of 108 



pi aue of 108 



theory of ] 59 



polarization by 127 



partial, usually produces elliptic polarization 138 



froin metals 138 



total, dues not polarize common light 138' 



from ruled surfaces produce colors 183 



changes plane of polarization IH5 



changes phase of undulatioji 198 



restores plane polarization in circularly or elliptically polarized light 197 



Refraction, angle of 108 



plane of 108 



theory of 159 



I'tolemy's experiments on 108 



law of 109 



index of , 108, 116 



phenomena of 110 



light polarized by 130 



light circularly polarized by 139 206 



. double, first mention of 114 



theory of, by Huyghena 160 



theory of, by Tresnel 215 



phenomena of 115-17 



planes of polarization in 218-20 



dii-ection of refracted rays in 160-61, 225 



Refrangibility, unequal, of the ditierent colors ... - 'ill 



Relation of vibration to undulation ] 51-53 



of dii-ection of molecular movement to piano of polarization 216-17 



Resistances, elastic, resultant of 218-20 



Resultant of compounded impulses in vibration 150 



of superposed undulations 160 



of elastic resistances in double refraction 218-20 



of molecular movement in double refraction 218-00 



of opi)()>^ite gyratory forces 198, 203 



Revolution induced in vibrating bodies 1^8 



when circular and when elliptic 150 



Rings, colored, seen in thin plates 118-20 



in crystals in plane polarized light 134-40 204-15 



in crystals in circularly polarized light I39 -^11 



elliptic, in topaz i:;9 



in two-axed crystals generally 2i:! 



Roemer, his determination of the velocity of light 1-jl 



Rotation of plane of polai'ization produced by magnetism XU 1 



Rotatory polarization, discovered 135 j .; | 



described ' i;i5 



produced by quartz ] 35 



by liquids 141 



by salts I40 



Pasteur's researches in 140 



theory of OOO 



Rotatory power, how related to crystallograpliic modification I35 



Ruled surfaces, colors seen in reflection from 183 



Saccharimeter, Soleil's 141 



Mitscherlich's ] 40 



Salts, rotatory polarization produced by 142 



Sections, circular, of surface of elasticity 221 



principal, of crystals lj(5 



of wave surface 226 



Scebeck, rotatory power of liquids discovered by 14 1 



Selenite figures colored in polarized light ] 3:5 



Shadows, sharp b' jundaries of jyO 



of minute bodies show diffraction fringes I75 



Snellius, law of refraction discovered by 109 



Solar light unpolarized 131 



Soleil's saccharimeter HI 



Sonorous uadulutious, molecular movements in Kjo 



velocity of, uniform J55 



compai'cd with those of light 171 



Sound, velocity of 153-55 



interferences in 1(;3 



molecular movements in ] go 



Spar, Iceland, crystalUne form II5 



double refraction by 11.5-17 



Spectra, produced by diffraction 182 



Spectrum, solar, colors of HI 



fixed lines in 125-26 



Spirals, Airy's, seen in quartz 13(5 



Stars, aberration of, a means of ascertaining the velocity of light 122 



Stereoscope, principle of, found in Galen's worlds 109 



