Meteorites, and Volcanic Agency. 501 



the planets, or the comets, the inference which we need not 

 hesitate to draw in either case is, that the masses in question 

 have been disintegrated by explosion. 



Here, however, we have to meet the same objection as in 

 the theory of disintegration by impact. When a cosmical 

 body of considerable magnitude, whether solid or in part fluid, 

 is sundered by explosion, there will be produced, in addition 

 to the numberless small fragments, large masses also, which 

 become meteorites, and set out in various orbits. We must 

 not, however, lose sight of the fact that meteorites, as we know 

 them, are, comparatively speaking, very small bodies ; and for 

 this reason we cannot support the view that the complete 

 breaking asunder of the mass had occurred at a single ex- 

 plosion. But the disintegration of such a cosmical mass may 

 be gradual. In place of a single explosion, we can conceive 

 a succession of them hurling portions of the surface into 

 space. Such an occurrence may take place on any cosmical 

 mass on which volcanic agencies may be active, and the mass 

 yet be so small that its gravitating power is insufficient to 

 attract again to its surface all the fragments which have been 

 hurled from it. 



Such considerations recall to mind the views long since 

 propounded by Olbers, Arago, Laplace, Berzelius, and others, 

 and recently put forth by Dr. Lawrence Smith, according 

 to which the moon, the gravitating force of which is one 

 sixth that of the earth, could propel fragments to such 

 distances that they would not return to her. The possibility 

 of such an occurrence in the case of the moon cannot be gain- 

 said ; the lunar surface covered with its numerous crater- 

 mounds shows that the greater portion of the ejected masses 

 have descended again to form the stony ramparts surrounding 

 the crater-mouths, and that even under the most favourable 

 conditions only few fragments have been scattered into space. 

 When the amount of meteoric matter which reaches our 

 earth annually is considered, such a source as the one in 

 question appears to be too insignificant. The meteorites reach 

 us from such a variety of directions, and fall so frequently, 

 that we must seek for a more general cause, lying not in the 

 moon alone, nor, in short, in any single member of the 

 system of heavenly bodies. 



In a number of cosmical bodies, then, of considerable di- 

 mension, yet sufficiently small to be unable to attract again 

 to their surface fragments hurled from them by explosion, 

 it is possible to conceive the conditions under which meteor- 

 ites are fashioned. It is highly probable that small star- 

 masses of such a kind may, during a certain period of their 



