LIGHT THE ETHER IN ITS RELATIONS TO 

 MATERIAL MOLECULES 



Sources of Light Reflection Refraction Scattering Absorption 

 How Colours are produced The Ether made for the Illu- 

 mination of the Universe The Finest Test of Order in the 

 Atoms and Molecules Does the Finest Work. 



II. THE ether in its relations to material atoms now falls 

 to be considered. Aggregates and combinations of matter 

 form the ordinary sources of light. In such a source 

 there are two parts, and two modes of operation. Chemi- 

 cal action produces heat motions in the ether. These 

 encountering solid matter are changed into motions that 

 are light-giving. To obtain a lamp, it is not sufficient 

 to raise heat of proper intensity. Another contingency 

 enters. 



Both requirements may be illustrated by what happens 

 in lighting a petroleum lamp. When first ignited its 

 flame is dull, and much smoke is given forth, much 

 carbon, not finding oxygen atoms with which to enter 

 into combination, escapes. The glass chimney causes a 

 draught. Oxygen is thus supplied in larger measure, 

 more of the carbon combines with it, the temperature is 

 raised, and, what is as important, a sufficient supply of 

 solid carbon remains in the flame to cause luminosity. 

 To produce the motions that are light-giving, there must 

 not only be atoms and molecules acting with burning 



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