

MEMOIR ON METEORITES. 297 



elevation of volcanic ashes and in matter swept into the air by 

 tornadoes, the latter from simple evaporation. In the one case 

 the matter is upheld by magneto-electric force; in the other 

 by the law of diffusion which regulates the blending of vapors 

 and gases, and by temperature. A precipitation of metallic 

 and earthy matter would happen on any reduction of the 

 magnetic tension ; one of rain, hail, or snow on a fall of tem- 

 perature. The materials of both originate in our earth. In 

 the one instance they are elevated but to a short distance from 

 its surface, while in the other they appear to penetrate beyond 

 its farthest limits, and possibly to enter the interplanetary 

 system. In both cases, however, they are destined, through 

 the operation of invariable laws, to return to their original 

 repository." 



This theory, coming as it does from one who is justly entitled 

 to high consideration from the fact of the special attention he 

 has given to the subject of meteorites, may mislead ; and for 

 that reason objections will be advanced which will doubtless 

 entirely set aside this notion of terrestrial origin, and to this 

 end I would consider two fundamental principles of it. First 

 of all it must be proved that terrestrial volcanoes contain all 

 the varieties of matter found in the composition of the mete- 

 oric bodies. There is no doubt that many of the varieties are 

 ejected from volcanoes, as olivine, etc. ; but then the principal 

 one, nickeliferous iron, has never in a single instance been found 

 in the lava or other matter coming from volcanoes, although 

 frequently sought for. 



But the physical obstacles are a still more insuperable diffi- 

 culty in the way of adopting this theory. In the first place it 

 is considered a physical impossibility for tornadoes or other 

 currents of air to waft matter, however impalpable, "beyond 

 the farthest limits of the earth, and possibly into interplanetary 

 space." Again, if magnetic and diamagnetic forces cause the 

 particles to coalesce and form solid masses, by the cessation of 

 those forces the bodies would crumble into powder. Another 

 strong physical objection to the theory is, that as the consoli- 

 dation of these masses is expected to take place in "magneto- 

 polar" regions, their fall should only be in those portions of 

 the earth ; for, like rain and hail (to which the consolidation 

 of these bodies are assimilated in this theory), they should fall 



