of the fall of Aerolites. 339 



probability of finding such bodies (had they fallen) in the 

 numerous quarries opened in all parts of the world, and in 

 the natural sections examined by so many geologists, much 

 greater than when they are sought for on the present surface, 

 obscured as it is by vegetation, or occupied by tillage. When 

 I made the remark as regards the aerolites, I thought it ori- 

 ginal ; but a note to Humboldt's Kosmos has shown me that 

 the illustrious Olbers had made it before me, and I am even 

 more gratified by finding that I had thus unconsciously drop- 

 ped into the same train of thought with that acute philosopher. 

 The passage occurs in his paper on falling stars in Schuma- 

 cher's Jahrbuch for 1838 ; and as it is one of great interest, I 

 shall extract it at length from the original, and not from the 

 abbreviation by Humboldt. 



M Finally, I may be permitted to mention a circumstance 

 which has not hitherto, so far as I know, been taken into con- 

 sideration by any one, and respecting which I would gladly 

 learn the opinions of well-informed philosophers and be in- 

 structed by them. It is this, that neither fossil meteorite 

 nor fossil meteoric iron has as yet been found. May we not, 

 nay, must we not conclude from this fact, that before the 

 last modification of the surface of our earth no meteorites had 

 ever fallen upon it? Would they not indeed be somewhat 

 frequently found in the secondary and tertiary strata if they 

 had been projected downwards on the earth for thousands 

 of years previously, when in the present time several hundreds 

 of such falls of scones take place yearly ? And although such 

 aerolites may not have retained so perfectly their original form 

 as the shells of mollusca and the bones and teeth of saurians 

 and of other vertebrata, yet must they have continued suffi- 

 ciently recognizable. I must confess that this fact appears to 

 me of great importance as regards geology and cosmology, 

 and deserves especial consideration in any inquiry into the 

 nature, formation, and source of aerolites." 



Such, then, is the opinion of Olbers ; and though it is stated 

 in a note to his paper that some fragments of aerolites had, by 

 long exposure to moisture whilst imbedded in damp earth, 

 been totally decomposed and reduced to a gray-looking sub- 

 stance mixed with peroxide of iron, it must be remembered 

 that many shells and other organic bodies have been also 

 destroyed and removed by decomposition, and that the total 

 absence of aerolites in the ancient strata cannot therefore be 

 accounted for by so partial a cause. Humboldt quotes two 

 examples of bodies supposed to have been aerolites; but it 

 does not appear from his statement whether they were found 

 in gravel, or whether there was any proof that they had been 

 previously imbedded in rocks ; and I think, therefore, it must 



