MEMOIR ON METEORITES. 299 



sected by our atmosphere, when they meet with the most 

 serious derangement, and fall to the earth's surface in whole 

 or in part. This may not occur in their first passage through 

 the atmosphere, but repeated obstructions in this medium at 

 different times must ultimately bring about the result. In this 

 theory their origin is supposed to be the same as that of other 

 planetary bodies, and they are regarded as always having had 

 an individual cosmical existence. Now, however reasonable 

 the admission of this orbital motion immediately before and 

 for some time previous to their contact with the earth, the 

 assumption of their original cosmical origin would appear to 

 have no support in the many characteristics of meteoric bodies 

 as enumerated some pages back. The form alone of these bodies, 

 is any thing but what ought to be expected from a gradual 

 condensation and consolidation. All the chemical and miner- 

 alogical characters are opposed to this supposition. If the ad- 

 vocates of this theory do not insist on the last feature of it, 

 then the theory amounts to but little else than a statement that 

 meteoric stones fall to us from space while having an orbital 

 motion. In order to entitle this planetary theory to any weight 

 it must be shown how bodies formed and constructed as these, are 

 could be other than fragments of some very much larger mass. 



As to the existence of meteoric stones in space, traveling 

 in a special orbit prior to their fall, there can be but little 

 doubt when we consider their direction and velocity, their com- 

 position proving them to be of extra-terrestrial origin. This, 

 however, only conducts in part to their origin; and those who 

 will examine them chemically will feel convinced that the earth 

 is not the first great mass that meteoric stones have been in 

 contact with, and this conviction is strengthened when we 

 reflect on the strong marks of community of origin so fully 

 dwelt upon. It is then in consideration of what was the con- 

 nection of these bodies prior to their having an independent 

 motion of their own that this memoir will be concluded. 



LUNAR ORIGIN OF METEORIC STONES. 



It only remains to bring* forward the facts already developed 

 to prove the plausibility of this origin of meteorites. 



It is a theory that was proposed as early as 1660 by an 

 Italian philosopher, Terzago, and advanced by Olbers, in 1795, 



