Manchester Memoirs, Vol. liv. (1909), No. 1. 9 



the solar system will be brought about by the means, and 

 in the order herein set forth, derives further support from 

 the fact that one of the stars of long recognised binary 

 systems is itself a close double star, revolving about its 

 common centre of gravity, as instanced in ju Herculis 

 and 7 Andromedae. 



31. Recapitulation. — (i) That the exact binary pro- 

 gression of the planetary distances is the primordial and 

 fundamental law (shining forth alone in the formless void) 

 from which the principal elements of the planetary orbits 

 have been derived ; (2) that the apparently irregular 

 differences from the law are the direct consequence of the 

 mutual attractions of the planetary bodies amongst them- 

 selves, but without affecting the validity of Kepler's laws, 

 as the distances and periodic times are necessarily 

 correlated ; (3) that as planetary systems have been 

 evolved in regular order from a nebular substance, so the 

 transformation of these systems will proceed in like order 

 to form the numerous binary and other revolving systems 

 observed in the immensity of the stellar universe. 



