LUMINOUS POWER. 119 



evidences that this has been the prevailing feeling of the 

 human race, derived, of course, from their observation of 

 the natural phenomena dependent upon luminous agency. 

 In the myths of every country, impersonations of light 

 prevail, and to these are referred the mysteries of the 

 perpetual renewal of life on the surface of the earth. 



This presentiment of a philosophic truth, in the in- 

 stance of the poet sages of intellectual Greece, was ad- 

 vanced to the liighest degree of refinement; and the 

 sublime exclamation of Plato : ' ' Light is truth, and God 

 is light," approaches nearly to a divine revelation. 



As the medium of vision as the cause of colour as 

 a power influencing in a most striking manner all the 

 forms of organisation around us, light presented to the 

 inquiring minds of all ages a subject of the highest 

 interest. 



The ancient philosophers, although they lost them- 

 selves in the metaphysical subtleties of their schools, 

 could not but discover in light an element of the utmost 

 importance in natural operations. The alchemists re- 

 garded the luminous principle as a most subtile fluid, 

 capabk of interpenetrating and mingling with gross 

 matter: gold being supposed to differ from the baser 

 metals only in containing a larger quantity of this ethe- 

 real essence.* Modern science,, after investigating most 



* It will be found in examining any of the works of the alche 

 mists, particularly those of Geber r De inveniendi arte Awi et 

 Argetiti, and his De AlcJiemia ; Roger Bacon's Opus Majus, or 

 Alchymia Major; Helvetius' Brief of the Golden Calf; or Basil 

 Valentine's Currus Triumpkalis, that in the processes of transmu- 

 tation the solar light was supposed to be marvellously effective. 

 In Boyle's Sceptical Chemist the same idea will be found pervad- 

 ing it. 



Amid all their errors, the alchemists were assiduous work- 

 men, and to them we are indebted for numerous facts. Of them, 

 and of their age, as contrasted with our own, Gibbon remarks: 

 " Congenial to the avarice of tbc human heart, it was studied in 

 China, as in Europe, with equal eagerness and equal success. The 



