To resume. Meteoric cosmogony has a rational basis. The modes of action it demands are still operative. Enfeebled almost to evanescence compared with the vigour they must have needed to be efficacious in world-building, they continue to make play in our nocturnal skies. They make play, it is true, with a very small quantity of material; but it may even now be distributed elsewhere in relatively enormous profusion, and in the solar system itself it presumably was much more abundant formerly than it now is. The earth has been raking up meteoric granules by hundreds of millions daily during untold ages, and her zone of space is still very far from being swept clean. The persistence of the supply, however, may be occasioned by the continual arrival of reinforcements from interstellar realms.
Comets appertain to, and travel with, the sun's cortège, and this is also inevitably true of comet-born meteors. But a multitude besides circulate independently of comets, and with much higher velocities. Their orbits are, then, hyperbolic; they belong to the category of 'irrevocable travellers,' and by their capture we are privileged to possess genuine shreds of sidereal matter. Universal space contains probably a vast stock of them, yet there is nothing to prove their collection into swarms. The spectroscope supplies no assurance to that effect; it has given its verdict against the meteoric constitution of nebulæ and temporary stars. And if we admit, through the persuasion of mineralogical testimony, that the aerolites so strangely landed on terrestrial soil are really the débris of ruined worlds, we can see for them no chance of restoration. Solitary they are, even if they occasionally pursue one another along an identical track, and solitary they must remain. Bodies do not of themselves initiate mutual circulation. Planetary or stellar outcasts cannot become re-associated into a gravitational system. Of a cosmic swarm, as of a poet, it may be said, Nascitur, non fit; and their birth-secret is undivulged.
FOOTNOTES:
[45] The New Astronomy, p. 197.
[46] American Journal of Science, vol. xi., p. 421, June, 1901.
[47] Carbon does not liquefy under ordinary conditions. In the production of his artificial diamonds M. Moissan employed tremendous pressure and great heat; and, although the genuineness of his products has been denied (Combes, Moniteur Scientifique, November, 1903), his methods at least seem to have approximated to those by which Nature fabricates her most authentic crystals.
[48] Sir R. Ball, The Earth's Beginnings, p. 243.
[49] Proceedings of the Royal Society, vol. xlv., p. 4.