341 



such laborious researches on falling stars and 

 their parallaxes, considered them as meteors 

 belonging" to the farthest limits of our atmos- 

 phere, between the region of the Aurora Borea- 

 lis and that of the lightest clouds *. Some 

 have been seen, which had not more than 14,000 

 toises, or about five leagues, of elevation. The 

 highest do not appear to exceed thirty leagues. 

 They have often more than a hundred feet dia- 

 meter ; and their swiftness is such, that they 

 dart in a few seconds over a space of two 

 leagues. Some of these have been measured, 

 the direction of which was almost perpendicu- 

 larly upward, or forming an angle of 50° with 

 the vertical line. This extremely remarkable 

 circumstance has led to the conclusion, that 

 falling stars are not aerolites, which, after hav- 

 ing hovered a long time in space, take fire on 

 entering accidentally into our atmosphere, and 

 fall toward the Earth 



Whatever may be the origin of these lumi- 

 nous meteors, it is difficult to conceive an in- 

 stantaneous inflammation taking place in a 



* According to the observations made on the ridge of the 

 Andes, at 2700 tosses of elevation, on the moutons, or little 

 white and fleecy clouds, it appeared to me, that their eleva- 

 tion is sometimes not less than 6000 toises above the level of 

 the coast. 



f Mr. Chladni, who at first looked upon falling stars as 

 aerolites, has lately abandoned this idea. 



