34 ORGANIC EVOLUTION CONSIDERED 



another at a distance through a vacuum, without 

 the mediation of anything else, by and through which 

 their action and force may be conveyed from one to 

 another, is to me so great an absurdity, that I believe 

 no man who has in philosophical matters a compe- 

 tent faculty of thinking, can ever fall into it. Grav- 

 ity must be caused by an agent acting constantly 

 according to certain laws; but whether this agent 

 be material or immaterial, I have left to the consid- 

 eration of my readers."* 



Again he writes in his queries: "Qu. 21. Is not this 

 medium much rarer in the denser Bodies of the Sun, 

 Stars, Planets, and Comets, than in the empty celes- 

 tial Spaces between them? And in passing from them 

 to great distances, doth it not grow denser and denser 

 perpetually, and thereby cause the gravity of those 

 great Bodies towards one another, and of their parts 

 towards the bodies; every body endeavoring to go 

 from the denser parts of the Medium towards the 

 rarer? For if the Medium be rarer within the Sun's 

 Body than at its surface, and rarer there than at the 

 hundredth parth of an Inch from its Body, and rarer 

 there than at the Orb of Saturn, I see no reason 

 why the increase of density should stop anywhere, 

 and not rather be continued through all distances 

 from the Sun to Saturn and beyond. And though 

 the increase of density may at great distances be 

 exceeding slow, yet if the elastic force of the medium 

 be exceeding great, it may suffice to impel Bodies 

 from the denser parts of the Medium towards the 

 rarer, with all that power which we call Gravity. 

 And that the elastic force of the Medium is exceed- 

 ing great, may be gathered from the swiftness of its 

 vibrations," etcf 



*On Light, by Stokes, p. 16. 



tModern Views of Electricity, by Lodge, p. 406. 



