38 FROM NEBULA TO NEBULA 



Gravitation acts uniformly in all directions, hence 

 we can picture our sun as surrounded by concentric 

 isogravitational spherical shells marking gradations of 

 his attractive power; and, going still farther, we can 

 even liken these shells to waves. Suc.h a sphere of in- 

 fluence in its course through space will necessarily 

 impinge upon other similar spheres, and cannot help 

 but cause "interference waves", answering to such as 

 occur on water. This undulatory effect is manifested, 

 I think, in the peculiar arrangement of the planets, both 

 as to their size and separating distances, an arrange- 

 ment that is moreover imitated with remarkable fidelity 

 by the subordinate systems. In this scheme of gravita- 

 tional harmonics wave crests are of course represented 

 by the larger bodies. 



It will naturally be very difficult to trace out any 

 definite structure of the heavens along these lines, since 

 we are not likely to be able to distinguish between the 

 "conjunctional" and the "elongational" arrangement of 

 stars and star-clusters. Nevertheless industry may yet 

 avail to detect its evidences. Elsewhere I give two other 

 keys to the probable structure of the sidereal system 

 that seem to me to bear a more definite stomp. 



Bodies which enter our system gently, as by "inter- 

 ference", will accommodate themselves to their new alle- 

 giance with a proper sense of duty. In other words, 

 they will spontaneously adjust both their speed and the 

 contour of their orbits so as to preserve, without shock, 

 the harmonious balance of the whole. This they can 

 do only by entering approximately circular orbits and 

 observing Kepler's third law: witness Neptune's small 

 eccentricity. 



But not all of our immigrants enter thus. Many, 

 like the comets, rush in violently as though seeking 

 refuge after being forcibly expelled from other realms. 



