156 SEE— DYNA^IICAL THEORY [April 19, 



also take place, in other star clusters of the Alilky Way. There are 

 in every region systems of bodies corresponding to our comets; and 

 as they travel in very elongated ellipses, they tend to build up the 

 bodies near the centers about which they revolve. In this way there 

 must be countless infinities of comets working in towards the centers 

 of the globular clusters ; and thus they build up the equality of the 

 stars in these regions, while at the same time the increase of mass 

 and the resistance to orbital motion thus arising tend to round up 

 the cluster and give increasing density towards the center. 



Thus the analogy of the comets revolving in very elongated orbits 

 and being destroyed to build up the planets and the sun, will also hold 

 in the building up of a cluster. Not only may mature stars be cap- 

 tured and adjusted to the average oscillation within a cluster, but 

 also myriads of millions of comets ; and it is in this way largely that 

 the cluster augments in mass and density towards the center. This 

 growth of central power in turn augments the condensation observed 

 in the clusters, and tends still further to produce a secular decrease 

 in volume; just as the planets are drawn nearer the sun by the 

 increase of the sun's mass. The shrinkage in the volume of a cluster 

 is thus analogous to the diminution of the dimensions of the primi- 

 tive orbits of the planets. And just as the planets in time will fall 

 into the sun, so also will the stars of a cluster eventually combine 

 into one great central star and thus produce an Arcturus or a 

 Canopus. 



The study of the system of comets about the sun, and the way 

 the planets have been built up near the center of the solar nebula, 

 thus gives us much light on the central accumulations noted in 

 globular clusters. The smaller masses drawn in from without tend 

 to augment the central bodies of the system ; and this growth of mass 

 in turn produces a further condensation of the original group, 

 whether it be a planetary system, or a globular cluster of the highest 

 order of glory and magnificence. 



