Solar spectrum, i. 58 myriads of ethereal waves constituting the seven colours of the, i. 58 rayless spaces crossing the, at right angles, i. 59 length of the undulations of the ether producing the impression of the colours of the solar spectrum, i. 59 mode of bringing the invisible rays of the chemical spectrum before the human eye, i. 59 fluorescence and calorescence, i. 60-62 experiments producing the long spectrum, i. 63 spectra of volatilized metals, i. 64 absorption of invisible rays, i. 65 discoveries of Sir Isaac Newton of the solar spectrum and the laws of coloured rings, i. 129 Fraunhofer’s lines, i. 129, 148 MM. Bunsen and Kirchhoff’s experiments, i. 130, 148 Mr. Glaisher’s experiments, i. 130 absorption bands, i. 131 Sir D. Brewster’s discovery, i. 131 coincident dark and coloured lines, i. 148 reversion of the coloured lines, i. 149 Prof. J. P. Cook’s discoveries, i. 149 M. Foucault’s discoveries, i. 149 M. Kirchhoff’s discovery of the law of exchanges, i. 150 metals shown by MM. Kirchhoff and Angström to exist in the sun, i. 151-153 and those proved to have no existence in the sun, i. 154 Solferino, production of, i. 127 Solids, the specific heat of compound, generally greater than that of their component elements, i. 101 Solorina, structure of the genus, i. 305 Solorina crocea, structure of, i. 306 Solorina saccata, structure of, i. 305 Space, matter wandering in, i. 28 Spearmint, absorption of radiant heat by the perfume of, i. 44 Specific gravity, i. 26 unit of, i. 26 Spectra, continuous, from glowing solids and liquids, i. 132 spectrum analysis, i. 133 experiments of Sir David Brewster and Mr. Fox Talbot, i. 133 spectrum of rubidium and cæsium, i. 136 of thallium, i. 136, 137 of indium, i. 137 of the flame of the iron in the manufacture of the Bessemer steel, i. 137, 138 of gases, i. 139, _et seq._ effect of high temperature on various spectra, i. 142-144 effects of pressure on a variety of gases and vapours, i. 145 of metals not always the same, i. 145 of the halogens, i. 146 of the vaporized mixture of five chlorides, i. 147 of lightning, 147 of the sun. _See_ Solar spectrum of the fixed stars, i. 155, 162, 163 of temporary and periodic stars, i. 156, 157 of the planets, i. 157, 158, 161 of various nebulæ, i. 158-160 Spermatozoids of confervaceæ, i. 210 Sphæria aquila, structure and habitat of, i. 295 Sphæria bombarda, structure of, i. 295 Sphæria, candle-snuff, habitat of, i. 295 Sphæria Desmazierii, development of, i. 294 Sphæria miliaris, characters of, i. 283 Sphæriacei, characters and habitat of the order, i. 293 development of, i. 294 Sphærobolus, force with which its sporangium is ejected, i. 273 Sphærococcoideæ, characters of the, i. 238