222 Observations on the Fall of Stones 



When we examine the cohesion of atmospheric stones, we find 

 that it is not the same before and after their fall. A great num- 

 ber of these stones are in such a soft state that thev are often 

 flattened on touching the ground, an.d those which fell in 1768, 

 1753, and 1808, &c. furnish a proof of this. The case has 

 been the same with others which have been observed in a state 

 of fusion and fiuiditv; like those which fell in 1731 at Lessay 

 near Coutanccs, andfinallv those collected in Poland in the year 

 1796. To conclude : all these stones became solid, and even 

 compact, some time after then- fall. This state of softness which 

 aerolites often present agrees verv well with their form, which 

 is almost ahvavs that of an obtuse triangle, or an oval flattened 

 on the lower side, a form which every body must present which 

 falls from a considerable height, if it does not possess great 

 solidity. 



As to the temperature of the aerolites, it is rarely like that of 

 the air : in general it is that of boiling water, since wliere they 

 fall in a certain state of softness they adhere to sheaves of 

 straw, or other combustible substances, without setting fire to 

 them. 



It has been asserted, since a certain number of aerolites has 

 been analysed, that tlieir elements were always nearly the same ; 

 but have all their constituent parts been minutely examined ? 

 For instance, has any account been given of the brown gluey 

 matter, similar to a varnish, which covered the stones of Benare.-s, 

 as well as those which fell in 1775, and, finally, which was dis- 

 covered on the aerolites which fell at \'alence in 1 806 ? This 

 gluey substance was also abundant on the stones of Stannern : 

 according to a description given of it, it seems to have been simi- 

 lar to cart-wheel grease. This viscous matter is probably a re- 

 sidue of that which in the preceding combustion was not entirely 

 consumed, and to which must he ascribed the smoke which these 

 stones emit frequently after their fall. 



There have been even aerolites differing from those hitherto 

 analysed : we ought to rank in this class the sm.all white stones 

 which, covered with ice, fell in Russia ; the white flints which in 

 1552 made so great ra'l'agos near Schleusinger in Bavaria, and 

 at the gates of Munich, and of which se^•eral specimens were 

 long preserved. Lastly, the stone which fell in Ireland in 1771, 

 and which resembled a grayish siliceous flint, like those precipi- 

 tated at Burgos in 1438, and which were so light that the largest 

 did not weigh half a pound, and some were only tlie size of 

 small ear drops. This last fact, however singular it may appear, 

 may be considered as correct, according to the account given of 

 it by M. Proust. 



Aerolites seem therefore, from all that has been observed, to 



liave 



