Chap. I.] Mechanical Philosophy. 17 



among them large enough to permit atoms of a 

 smaller size to pass freely through. The condi- 

 tion of the matter of the heavens, under the ac- 

 tion of fire at the sun, was chamah; the stretims 

 of light from the sun, moon, and stars, were 

 ashteroth; and the grains of air returning fiom 

 the circumference of the heavens to the sun, were 

 baalim. Concrete matter, however, is often so 

 constituted as not to be permeable \ciy easily, 

 but to resist. The several sorts of atoms cOiU- 

 posing the fluid matter which occupies iminea- 

 surabJe space, are the moving powers by winch 

 God acts upon ai>d regulates the machinery of 

 the universe. The more compact or unyielding 

 modifications of it constitute the great orbs, or 

 machines, to be urged along by their impulse. 

 Tiie latter are the chariots, and the former the 

 drivers. When, therefore, light, impelled by the 

 sun, strikes the side of such a body as the earth 

 we inhabit, it excites heat in that part, and the 

 spirit, or air, being rarefied, or made to recede 

 thereby, motion is communicated to the whole 

 orb. The motion thus begun, is promoted and 

 continued by the vast and incessant pressure of 

 the dark, cold, and dense matter on the opposite 

 side. And thus the globe being started by the 

 lessening of pressure on one side, and the aug- 

 mentation of it on the other, its diurnal and an- 

 nual revolutions were soon impressed upon it by 

 a little variation of tlie forces. The like reason- 

 ing he applied to the moon, and to all the other 

 planets and their satellites. By the operation of 

 lightj thus sent out from the sun, and acting upon 

 the other fluid matter of the heavens, and upou 

 Vol. I. C 



