STONES FALLING FROM THE AIR. 
24* 
Duration 
greatly varies, 
Noise of ex- 
plosion. 
The great 
differences of 
velocity shew 
that they ase 
not moved 
principally by 
their weight. 
greater than what would have been received from a simple fall. 
Besides, according to a great number of observations, it is quite 
uniform, and not augmented with the time of the passage of 
these stones through the air. 
The duration of this phenomenon seems also to present great 
variations 5 for example, it varies from a quarter of a second to 
some minutes ; one singular circumstance is the deep noise 
which resembles the report of cannon, and almost always 
accompanies the fall of aerolites, lasted in an explosion which 
took place in Russia in 1/87* f° r four entire hours, that is 
from one o’clock till five before the stones fell. It was also 
observed in 1200, before the fall of stones which took place near 
Abdona, in Italyf, that the cloud from which the stones were 
precipitated as if on fire, remained visible for near two hours. 
It may be further considered as a fresh proof, that besides 
their weight, there is a power which influences the direction of 
aerolites, on remarking the small depth these stones penetrate 
into the earth. Long ago it has been observed, that if left to the 
action of their own weight, these stones ought to enter very 
deeply into the earth, if the moon was their point of departure, 
and that their velocity ought to be influenced by their volume, 
or their mass. This, however, is so far from being the case, 
that in a shower of stones, which took place 17ri8,in Maine, and 
another in I7g0, in Gascony, there were several that fell with 
very little celerity, others very slowly, and others more swiftly $ 
some, in short, with such rapidity, that they made a loud 
whistling in passing through the air j and these differences in 
velocity were not at all governed by their weight. Lately, one 
of the stones that fell at Thoulouse in 1812, of which the density 
was the same as usual, touched the earth so lightly that it 
scarcely left any impression of its fall. Some other stones 
likewise, that fell at Agen, had not the force to penetrate the 
roofs on which they rolled : this was also observed in the stones 
that fell in 1755 near Tabor J. 
* Journal de Physique de Gilbert, tom. XXXI. 
f Izarn Lithologie Atmospherique. 
t History of the Aerolites that have fallen in Bohepia, by Mayer, 
Dresden) 1805. 
It 
