234 



INDEX. 



Page. 



Elliptic revolution of vibrating body 150 



rings seen in topaz 139 



in crystals of two axes generally 213 



Equal wave and ray vtloeity, lines of 2il(i 



Equation of surface of elasticity ' 217 



of wave surface 225 



of Interfering or superposed waves 1H6 



of waves normal to each other compounded ItiS 



of lemniscate curves 214 



Ether luminiferous 158 



incompressibility of KH 



density of, in different bodies 158 



elasticity of, in crystals 162, 215-20 



Euclid, his treatise on optics 1U8 



Extraordinary ray, definition 115 



Eye-piece, Delezenne's i:52 



Nicol's 132 



tourmaline 132 



Failure of Frcsuel's formute for reflection, case of 138, li'ti 



Figures in selenite, under polarized light 133 



Fixed lines in the spectnim 125-27 



Fizeau, his experiments on the velocity of light 122-23 



Fluid, elastic, body vibrating in 151 



tremors produced in 152 



undulations generated in 151-53 



molecular movements in 157 



Formula general, for resultant vibrations 150 



for dispersion 15(5 



for interference fnnges 170 



for diffraction do 176 



for reflection and refraction 18i)-95 



for chromatics of polarized light 207-08 



for lemniscates in two-axed crystals 214 



Forms, primitive, of crystals 141 



Foucault, his experiments on the velocity of light 124-25 



Fraunhofer, his discoveries in the spectrum 126 



his measures of undulations 171 



Fresnel, his analysis of light in the axis of quartz 1. 6 



his rhomb for circular polarization 137 



interference experiment with mirrors 168-69 



foi'mulffi for reflection, case of failure .<. 138, 1;'6 



equation of the wave surface j» 225 



of the surface of elasticity 217 



theory of undulation 162, 106 



of double refraction 162, 215-24 



Fringes of interference, measurement of 170 



displacement of 171 



Galen, principle of the stereoscope stated by 509 



Galileo, his experiments on the velocity of light 121 



Glass pUes used for polarization 130 



transparency of 131 



Gratings, diffraction produced by 181-83 



spectra do 182 



Grimaldi, first observer of diffraction 114 



Grimaldi's crests, diffraction fringes so-called 176 



Gyration of molecules in circular or elliptical polarization 197 



resultant of opposite 198, 203 



virtual in crystals having rotatory power 203 



Heat and cold, polarization produced by 1 40 



Heat, effects of, on crystals 141 



Iceland spar 141 



sulphate 01 lime 141 



glauberite 141 



Hemihedral crystals produce rotatory polarization 142 



Hemihedrism, relation to rotatory power 142 



Herapathite, used as a polariscope 1^*2 



Herschel, Sir John, his observations on plagihedral quartz . 135 



Huyghens, polarization obsei'ved by, in double refraction 116 



his theory of ethereal undulations 161 



of reflection and refraction IJiiJ 



of double refraction 160-61 



his principle of elementary wave-composition 1.57 



Iceland spar, form and characters of 115 



double refraction by 115-17 



Impact of elastic bodies ". 158 



Incidence, angle of 108 



limiting for total reflection 138 



Incompressibility of the ether •- IM 



Index of refraction 109 



in doubly refracting ci-ystals 116 



Inosculation, points of, in the wave surface 225-30 



Interference, cause of colors in Newton's 'rings 183-87 



in crystalline plates 204-15 



of fringes in diffraction 172-83 



does not occur in circularly polarized rays oppositely gyrating 203-4 



common origin of rays necessary to 168 



produced by two slightly inclined mirrors 168 



