STONES FALLING FROM THE AIR. 
29 
there see a kind of slow formation of aerolites. The facts we 
have already related sufficiently explain why, under several 
circumstances, the cloud precedes the fall of the aerolites ; for 
it contains all the substances of which they are composed, and, 
in this view, the phenomenon may, in a certain respect, be com- 
pared with the solution of salts. 
It appears, lastly, that, by supposing the power which sup- The projeotile 
ports these globes of lire as resulting from the inflammation or 
the formation of vapours, we do not admit of an unfounded from their 
hypothesis. For, in fact, whenever these globes burn with 
little energy, the matter of which they are composed falls very 
soon, while they rise again as soon as ever the inflammation 
is renewed. This is also the case in our rockets, where the 
force of ignition raises and sustains masses of a considerable 
weight. This force likewise employs its action on the course 
of the aerolites ; and, as it is opposed to their weight, it 
obliges the stone to follow an intermediate direction between 
the two impulses it receives. Observation proves, that aero- 
lites fall in proportion as the tire is extinguished, and that when, 
as at Connecticut, the combustion is again increased and ac- 
companied by explosions, the stone rises in the air again. 
From these facts it may be imagined, why this class of phe- Why these 
nomena is so frequent in the warmest months, and so rare in depen(l*on"^* 
•winter j and why they appear in the evening very frequently seasons and 
• accompanied by storms. The causes of these phenomena, Thev resemble 
though in appearance so different, have, nevertheless, some 
lelation to each other. Ram, tor example, is only the effect of spects. 
a precipitation of the water which is continually rising in the 
air, and aerolites probably depend only upon the precipitation 
of a great number of substances which are continually evapo- 
rating, and of which the reaction on each other may form new 
combinations. This hypothesis will not appear unfounded if 
we attend to the immense quantity of compound substances 
which organic bodies, staguanl waters, and all Ixxlies which are 
in a state of decomposition, incessantly exhale, and are lost in 
the air without its being known what afterwards becomes of 
them. It is very natural, therefore, to inquire what means 
nature 
