288 INDEX. 



Lichens : "brilliancy of the colours of, i. 304 

 Lichina, characters of the genus, i. 310 

 Lichinei, characters of the group, i. 310 

 Life, the mystery of, i. 97 



instances of individual combined with a common life in the lower 



orders of animals, ii. 38 



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 



