Such answer as may be ventured, must be taken less as a positive answer thanas a demurrer to the conclusion that the proximate result must be the ultimateresult. If, pushing to its extreme the argument that Evolution must cometo a close in complete equilibrium or rest, the reader suggests that foraught which appears to the contrary there must result a Universal Death whichwill continue indefinitely, two replies may be made. The first is that theevidence presented in the heavens at large implies that while of the multitudinousaggregates of matter it presents, most are passing through those stages --which must end in local rest, there are others which, having barely commencedthe series of changes constituting Evolution, are on the way to become theatresof life. The second reply is that when we contemplate our Sidereal Systemas a whole, certain of the great facts which science has established implypotential renewals of life, now in one region now in another, followed, possibly,at a period unimaginably remote by a more general renewal. This conclusionis suggested when we take into account a factor not yet mentioned.
For hitherto we have considered only that equilibration which is takingplace within our Solar System and within similar systems; taking no noteof that immeasurably greater equilibration which remains to take place: endingthose motions through space which such systems possess. That the stars, inold times called fixed, are all in motion, has now become a familiar truth,and that they are moving with velocities ranging from say 10 miles per secondup to some 70 miles per second (which last is the velocity of a "runawaystar" supposed to be passing through our Sidereal System) is a truthdeduced from observations by modern astronomers. To be joined with this isthe fact that there are dying stars and probably dead stars. Beyond the evidencefurnished by the various kinds of light they emit, of which the red indicatesrelatively advanced age, there is the evidence that in some cases brightstars have attendants which are dark or almost dark: the most conspicuouscase being that of Sirius, round which revolves a body of about one-thirdits size but yielding only 1/30000th part of its light -- a star approachingto our Sun in size, which has gone out. The implication appears to be thatbeyond the luminous masses constituting the visible Sidereal System, thereare non-luminous masses, perhaps fewer in number perhaps more numerous, whichin common with the luminous ones are impelled by mutual gravitation. Howthen are to be equilibrated the motions of these vast masses, luminous andnonluminous, having high velocities?
This question may be divided into two, a major and a minor, of which theminor admits of something like an answer, while the major seems unanswerable. §182a. Scattered through immensurable space, but more especiallyin and about the region of the Milky Way, are numerous star-clusters, varyingin their characters from those which are hardly distinguishable from unusuallyrich portions of the heavens, to those which constitute condensed swarmsof stars; kinds of which may be named, as at the one extreme, 24 Persei,103 Cassiopeia and 32 Cygni, and at the other extreme, 13 Herculis and 2Aquarei.(*)<fn* The clusters here named are exhibited in Dr. Isaac Roberts'ssplendid series of Photographs of Stars, Star-Clusters, and Nebulae (two vols.), in which also will be found the references presently to be made.>
The varieties between these extremes were regarded by Sir William Herschelas implying progressive concentration; and in his opinion Sir John Herschelapparently agreed. Pursuing the argument the latter wrote: --"Among a crowd of solid bodies of whatever size, animated by independentand partially opposing impulses, motions opposite to each other must producecollision, destruction of velocity, and subsidence or near approach towardsthe centre of preponderant attraction; while those which conspire, or whichremain outstanding after such conflicts, must ultimately give rise to circulationof a permanent character." ( Outlines of Astronomy, 9th ed., p.
641.) The problem, however, is here dealt with purely as a mechanical one: the assumption being that the mutually arrested masses will continue as masses.
