METEORS AND AEROLITES. 279 



notion that these aerolites may be the product of our own 

 volcanoes; stones forcibly ejected thence, partaking for a 

 time of the motion of the earth, but in the end returning to 

 it. The negative evidence here is so obvious and complete, 

 that we have no need to do more than slightly refer to it. 

 This opinion has no longer an advocate. 



A second hypothesis, involving telluric origin, has little 

 more of proof or probability to recommend it. This is, that 

 stones do not actually fall, but that lightning or electricity 

 in some meteoric shape, impinging upon the earth, fuses the 

 earthy and metallic materials on the spot so as to admit of 

 their re-consolidation in these new forms. Other refutation 

 of this opinion is not needed than a simple regard to the 

 composition of aerolites, to their occasional magnitude, and 

 to the great number often appearing at the same time. But, 

 in truth, the notion is one that was never more than vaguely 

 held, and has long since been given up as untenable. 



Another solution still has been proposed, also deriving the 

 phenomena from terrestrial causes. This is the hypothesis 

 of atmospheric origin ; adopted by many in the outset of the 

 enquiry, from the seeming difficulty of carrying speculation 

 beyond the limits of our globe. Using the fact just ascer- 

 tained of the identity of the materials of aerolites with 

 elements existing on the earth, they assumed (but without 

 explaining the manner or course of such operation) that these 

 elements might be slowly absorbed into the atmosphere ; and 

 retained there in a state of extreme diffusion, until some 

 accidental agency (either electrical or force of other kind) 

 caused their sudden aggregation, and precipitated them on 

 the surface of the earth under the forms and conditions 

 actually observed. In this theory the light, heat, and deto- 

 nation attending their fall, were attributed to the vehemence 

 of the forces and actions bringing these substances into a 

 solid form from their highly diffused or gaseous state. The 



