512 



PHYSICAL SCIENCES. 



RADIAL. 



RADIAL force producing periodical 

 changes in relative positions of the 

 heavenly bodies, 15 ; effects pro- 

 duced by, 16, 17 ; principle neu- 

 tralising its ultimate result, 19, 20. 



Radiation of heat, laws regulating, 

 257 ; universal from substances, 

 268 ; natural phenomena resulting 

 from, 269 ; slow decrease of the 

 earth's central heat from, 232 ; 

 influence of, on temperature, 239 ; 

 power of, in water compared with 

 dry land, 242 ; of heat, a transfer 

 of motion, 277. 



Radii vectores, signification of, 8 ; 

 areas described by, 10 ; force dis- 

 turbing in the direction of, 14, 15. 



Ragona-Scina, M., his theory of ray- 

 less lines in the spectrum, 163. 



Rain, force shaping drops, 106 ; cause 

 of periodic tropical, 123 ; region 

 of, 124 ; theory of its formation, 

 270 ; an electric conductor, 292. 



Rankine, Mr., his theory of the struc- 

 ture of matter, 1 04 ; his theory of 

 the absorption of light, 177. 



Rays, common nature and common 

 properties of, 268. 



of heat, existing independently 



of luminous, 257 ; laws of trans- 

 mission of, 258 ; analogy between 

 transmission of luminous rays and, 

 259 ; temperature of their source 

 affecting transmissson, 260 ; vary- 

 ing in nature with their origin, 

 261 ; transmitted through coloured 

 glass, 262 ; traversing various 

 media, 6. ; subject to refraction 

 and reflection, 263 ; polarized, 265- 

 267 ; absorption and reflection of, 

 268 ; rotation of polarized, caused 

 by magnetism, 319. 



' of light, bent by passing from rare 



into dense media, 153 ; partial and 

 total reflection of, 156 ; loss of, by 

 obliquity of incidence, 158 ; theory 

 of their transmission and absorp- 

 tion, 159-161 ; comparative refran- 

 gibility of, 163 ; experiments on 

 dispersion of, 164 ; principle deter- 

 mining their colour, 170, 171 ; 

 transmission of, in glass or water, 



REFRACTION. 



177, 178; conditions of polarized, 

 179; double refraction, 181-183; 

 polarized by reflection, 184, 185 ; 

 coloured images produced by inter- 

 ference of, 194, 195 ; internal dis- 

 persion of, 195-198; heat, light, 

 chemical action, independent pro- 

 perties of, 214, 215 ; undulations 

 constituting, 223 ; conditions mo- 

 difying the power of solar, to pro- 

 duce heat, 237 ; transmitted inde- 

 pendently of calorific rays, 258 ; 

 magnetizing of polarized^ 318, 319. 



Rays, solar, effect produced by their 

 refraction in lunar eclipse, 40 ; 

 passing between lunar mountains 

 in solar eclipse, 41. 



of the solar spectrum, their 



chemical properties, 203 ; varying 

 chemical energy, 207, 208 ; varying 

 nature of their action, 208 ; pecu- 

 liar chemical action of the red, 

 209-211 ; deoxydating and oxy- 

 dating action of, 211, 212 ; expe- 

 riments detailed, 212-215 ; new, 

 obscure, detected by Sir John Her- 

 schel, 217. 



Red Sea, the, tide in, 98. 



Reflection of waves of sound, 137, 

 138 ; of rays at surfaces of strata 

 differing in density, phenomena oc- 

 casioned by, 156, 157 ; affecting 

 colour, 160 ; motion of a ray of 

 light in, 177 ; light polarized by, 

 184, 185 ; elliptical polarization 

 produced by, 193 ; heat polarized 

 by, 266 ; of radiant heat from 

 surfaces, 268. 



Refraction of the sun's rays in lunar 

 eclipses, 40 ; of waves of sound, 

 138 ; of light by the atmosphere, 

 153, 154; mode of estimating, in 

 case of celestial bodies, 155 ; for- 

 mulae obtaining in case of terrestrial 

 objects, ib. ; phenomena occasioned 

 by, 155, 156 ; colours decomposed 

 by, 159, 160; produced without 

 colour, 164, 165 ; power of, ia 

 media affecting the elasticity of the 

 luminous ether, 177 ; of a polarized 

 ray, 180 ; double, 181, 182 ; Fres- 

 uel's theory of, 183 ; diminished 



