Light, probable cause of the, of the sun, i. 28 Drummond’s light, how produced, i. 30 intensity of the, of the electric spark, i. 32 chemical action of, i. 34 amount of force exerted by the sun’s light within the limits of the terrestrial atmosphere, i. 34 constancy of the amount and refrangibility of light and heat absorbed and radiated, i. 34 causes of colour of flowers, leaves, dyed cloth, and gold and copper, i. 35, 36 property of some substances in the transmission of radiant light and heat, i. 36 invisible rays of high heating power existing beyond the red end of the solar spectrum, i. 36 Melloni’s investigation of the laws of radiation and absorption of radiant heat in solid and liquid matter, i. 38 chemical power of the light of the moon and stars, i. 55 and of solar light, i. 56 effect of the opalescence of the atmosphere on the light of the sun, i. 55 probable causes of the blueness of the sky, and the brightness of the tints at sun-rise and sun-set, i. 58 solar spectrum, i. 58 myriads of ethereal waves constituting the seven colours of the, i. 58 fluorescent or degraded light, i. 60 experiment illustrating the change of heat into light, i. 62 absorption of invisible rays, by solids, liquids, and gases, i. 65 causes of earth light, i. 66 polarization of light and heat, i. 68, 69 by reflection and refraction, i. 69 relation of polarization to crystallization, i. 70, 71 M. Gassiot’s experiments on stratified electric light, i. 78 influence of magnetism on the stratified light, i. 78 cause of the stratified discharge, i. 85 effect of varied intensity on electric discharges, i. 86 action of magnetism and electricity on light, i. 90 delicate power of analysis in light, i. 95 Dr. Young’s establishment of the undulatory theory of light, i. 129 Drummond’s light, i. 132 coloured light obtained from the combustion of the salts of different metals, i. 132 effects of light on vegetation, i. 168, 169 effects of light as an exciting cause in the vegetable world, i. 431 Lightning, spectrum of, i. 147 Ligneous tissue, i. 174, 175 Liliaceæ, structure and development of the, i. 388 Limboriei, structure and habitat of the, i. 310 Lime, carbonate of, different modifications assumed by, i. 74 chloride of, properties of, i. 19 oxalate of, formation of, i. 117 Limestones, probable history of the oldest, ii. 52 the nummulitic, ii. 53 the limestone formed by the Eozoön Canadense, ii. 54 Limnoria lignorum, structure of, ii. 203 Limpet, structure, food, and habitat of, ii. 238, 239 Limulus, fossil remains of, ii. 211 Lindsæeæ, characters of, i. 351 Lingbya, structure of, i. 213 Lingula flags, fossil animals composing the, ii. 53 Listera ovata, structure and mode of reproduction of, i. 399