THE AUTHOR'S THEORIES OUTLINED 33 



say it is "because the sun pulls them with him by main 

 force, that of his attraction". 



It seems to me self-evident that our Present Order 

 could never have existed as long as it manifestly has, or 

 that it can continue to exist beyond to-morrow, without 

 the presence of some single, all-embracing, co-ordinating 

 dynamical principle underlying the whole cosmos. In 

 casting about for this principle, where shall we find one 

 so eligible or readier to hand than that of universal 

 gravitation itself, with the emphasis on the adjective? 

 Let this, then, be our line of inquiry: What effect, if 

 any, has the factor of the mutual attraction between the 

 solar system, on the one hand, and the remainder of the 

 universe, on the other, upon the conduct of the former? 



CELESTIAL MOTIONS 



In the outset let me say that I shall not undertake to 

 discuss the essence of gravitation, or to explain how it 

 acts across the void. Let these for the present be taken 

 for granted. All I desire now to interpolate in this con- 

 nection is, that it is no greater tax upon our powers of 

 comprehension to understand how gravitation can extend 

 from the earth to a star than how it manages to span 

 the blank between the earth and a balloon, or between 

 the sun and Neptune. The only way to settle the 

 question is to put our hypothesis to the test. If gravita- 

 tion does not extend from the earth to the stars, the 

 phrase universal gravitation is a misnomer. On the 

 other hand, if it does so extend, the present theory of as- 

 tronomy, which leaves the factor of the stellar attractions 

 entirely out of the reckoning, cannot possibly be final. 

 This work, so far as I am aware, constitutes the very 

 first attempt to repair this grave omission. 



The first important point to consider is the nature 

 and composition of this resultant of the stellar attrac- 

 tions. Pick out one particular star and consider it 

 separately with reference to our earth. Obviously, a 

 mathematically straight line connecting the center of 

 mass of the earth with the center of mass of the star will 



