CHAP X. 



Of Ether, and of ike Weight and Elasticity of 

 the Air. 



PAGE 



1. That ether is a fluid more subtle than the air . 68 



2, 3, 4. The ancients describe ether to be a subtle, 



active fire, which diffuses itself through the uni- 

 verse . . 68- 69 



5. The nature of air, as well as ether, clearly under- 

 stood by the ancients . .' ib. 



0, The general notions respecting fire 70 



CHAP. XL 



Newton's Theory of Colnurs, indicated ly Pythagoras 

 and Plato; 



5. That colours result from the different modifications 



of reflected light . 72; 



2. Diversity of colours formed by the combined inter- 



mixture of others r 7$ 



3. That light is the action of a subtle matter upon the 



organs of light . . 74 



4. Experiment respecting light . r 7$ 



2 



