STONES FALLING FROM THE AIR. 
243 
fall 3 but it is almost always the contrary, and several stones 
that have been observed in the air b?u 7 e been extinguished before 
they reached the ground The form of these meteors also 
agrees very well with this opinion*, for it is not always the 
same 3 the stone that fell in England on the 18th of August, 
1785, assumed at one lime a round form, and at others was 
more lengthened out The effervescence so remarkable, that 
has been observed in several of these aerolites, appears to 
prove still farther, that they have not the metallic consistence, 
nor that these are simple vapours which surround the stone, 
because the edges arealw’ays very distinct, and are not insensibly 
shaded off. In short, if contrary to all probability, the greatest 
part of this<<neteor were to be attributed to the vapours, it 
would be equally embarrassing to explain their origin 3 since the 
aerolites are almost entirely composed of earthy and metallic 
parts, which can hardly be converted into vapour at the tempera- 
ture of our atmosphere. 
The aerolites are said to have generally moved in a parabolic Whether these 
orbit 3 but the angle which the parabola forms with the horizon ^°^| 1 l0vem 
is not always the same. In France, in the year 1785, a stone Proof to the 
fell which made a hole that was nearly horizontal, and that 0 f contral > 
Stannernf formed a cavity of two feet ^nd only two inches in 
depth. Other stones, like that which fell at Orleans in 1810, 
or that which was observed in Calabria in the year 1755, con- 
stantly preserve in their fall an almost perpendicular direction. 
These facts seem to indicate that besides gravity, there is some 
2 her force which, opposed to the direction of their weight, may 
odify their course. We have a fresh proof of this in the 
aerolite of Connecticut, which, before it was extinguished, and 
after having exploded three times, rebounded an equal number 
of times upwards, and consequently took a direction totally 
opposite to that which its weight might have caused. 
With regard to the velocity of aerolites, it appears in general Their velocity, 
very great 5 and often equals or even surpasses that of the 
earth’s rotation 3 but in all these cases the acceleration is much 
* See the work of Chladni, on masses of iron fallen from the sky. 
f Journal de Gilbert, volume already referred to. 
greater 
