156 LIGHT AND COLOUR?. [Lesson xxv. 



inhabit, raising in our minds the most exalted 

 ideas of the Divine perfections ! We may also here 

 observe, that the all -wise CREATOR has so divided 

 our time into day and night, light and darkness, 

 that we may never forget that all things in human 

 life are mixtures of good and evil. Heaven is said 

 to be all light, and hell is as frequently represented 

 to be utter darkness : wherever the favour of GOD 

 shines, there is light ; 



" His presence gives eternal day, 



And makes eternal rest ;" 



ljut his absence and anger create darkness. 



By Light, I would wish to have understood, that 

 principle by which objects are made perceptible to 

 our sense of seeing; or the sensation occasioned in 

 the mind by the view of luminous objects. The 

 nature of Light has very long been a subject of 

 philosophical speculation: the earliest philosophers 

 doubted whether objects became visible by means 

 of any thing proceeding from them, or from the 

 eye of the spectator. On this subject, opinions 

 are still afloat. It is thought by some, that Light 

 may be a fluid (per se) equally diffused through the 

 universe; the action of the solar, or other rays, is 

 necessary, according to this hypothesis, to give it 

 motion, and make its effects perceptible. Others 

 are of opinion, that Light is a quality , which can- 

 not exist independently of matter, and which re- 

 quires the assistance of the solar and other rays, to 

 bring it into action. But as the hypothesis of New- 

 ton is the most generally received, what I shall say 



on 



