340 
STONES FALLING FROM THE AIR. 
Those observers who, on the contrary, have given an atmos- 
pheric origin to aerolites, have thought, 
that they are 1st. That they have been produced in ocr atmosphere by the 
the air - combustion of inflammable gases, which contain in suspension 
or in solution, metallic or earthy particles, 
or otherwise 2d. Or they have been produced in the same manner as the 
produced, me tals and earths are formed in plants, as the experiments of 
Schrader and Crell seem to have proved. These philosophers 
have observed, that by causing plants to vegetate in sulphur or 
charcoal, the metals or earths which they usually contain, are 
also produced in them, under these circumstances, by the act of 
vegetation. 
or that they As to the natural philosophers who have attributed a ter- 
iMi^but^bcen restria l origin to aerolites, some have admitted* that these sub- 
changed by stances pre-existed in the places where they were found, having 
lightning. r r & 
only been changed by lightning, and that they proceeded from 
volcanos, and are a species of lava. 
The opinion which tends to make aerolites be considered as 
formed by new combinations supposed to take place in the at- 
mosphere, by the contact of all those bodies which evaporation 
incessantly carries thither, is so little known, that it is the only 
one to which we shall direct our observations. 
The present The authors of this hypothesis first made the observation, 
confine^to the fall of aerolites does not appear to take place equally 
their produc- in all seasons 3 for out of sixty-five or sixty-six of these falls, 
tion isthe air. ^ e pocha is well known, near two-thirds have hap- 
pened during the months of June, July, and August. And 
lastly they prove still farther, that in all the winter months the 
fall of stones is much less frequent than in a single month of 
summer. 
At what time The same observation which demonstrates the influence of 
°tones ^have seasons on f he fall of aerolites, equally applies to the difie- 
fallen ; rent parts of the day 3 for in a catalogue made with care of all 
falls of meteoric stones that have been known, seven only have 
* This was the opinion of the members of the Royal Academy of 
Sciences, during the middle, aud towards the end, of the last century. 
fallen 
