On the Origin (^'Meteoric Stones. 81 



according to our hypothesis, accumulate in the highest regions 

 of the atmosphere ? Perhaps falling stars, fire-balls, northern- 

 lights, and meteoric stones, are the means by which Nature either 

 transforms them into her own essence, or returns them directly 

 to the earth. 



It appears to me to be very favourable to my hypothesis, that 

 all these appearances universally occur only in the upper, never 

 in the lower regions of the atmosphere, for which no cause could 

 be assigned were both these regions of the same nature. 



Do we attempt now to determine how and by what means Na- 

 ture accomplishes the reduction of these vapours ? We enter, it 

 must be allowed, on a dark domain, where we can only venture 

 upon conjectures. Before, however, we can make an attempt to 

 solve this question, it may be proper to obviate one of the chief 

 objections against the atmospheric origin of meteoric stones. 



Such objection is taken from the greatness of the space requi- 

 site to furnish materials for the formation of a stone of consider- 

 able size. The known masses of iron in Siberia and Chili^ which 

 have the character of meteoric stones, weigh more than 1000 lb., 

 and one newly discovered in Brazil^ is estimated at 14,000 lb. 

 Would not, it may be demanded, the formation of such a stone 

 exhaust a space equal to an entire ocean of air, and put the 

 whole atmosphere into commotion ? 



This difficulty disappears when we begin to reduce the matter 

 to measure and number. The air is, indeed, in small masses, 

 very light ; but masses of moderate dimensions are heavier than 

 might at first be supposed. It may be calculated from the very 

 accurate experiments executed by Messrs Biot and Arago, that 

 a cubic Prussian foot of air, at zero of Reaumur, and barometer 

 28 inches, weighs nearly 2| loth* Prussian. Hence it follows, 

 that a single cubic rood f weighs about 148 lb., consequently more 

 than 1^ cwt. Did meteoric stones originate in the lower regions 

 of the atmosphere, very moderate space would therefore be suf- 

 ficient for their formation. The air, however, in the upper re- 

 gions, where said meteors are generated, is very much rarified ; 

 and this also must be taken into calculation. Since the barometer 

 on the most elevated mountains, consequently about the height 



• Loth equal to half an ounce, 

 f Rood equal to 11 Paris feet, 7 inch. 2 lin. 

 VOL. XVI. NO. XXXI. JANUARY 1834. ¥ 



