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The zig-zag kind of lightning is extremely dangerous, because it must 
overcome a very violent resistance of the atmosphere, and wherever that 
resistance is in the smallest degree lessened, there it will undoubtedly strike, 
and even at a considerable distance. It is otherwise with that kind which 
appears m flashes of no determinate form.} the electric matter of which is 
evidently dissipated in the air by some conducting substances which are pre¬ 
sent there, and they are therefore rendered less powerful. 
The most destructive kind of lightning is that which assumes the form of 
balls. These are produced by an exceeding great power of electricity, gra¬ 
dually accumulated till the resistance of the atmosphere is no longer able to 
confine it. In general, the lightning breaks out from the electrified cloud 
by means of the approach of some conducting substance; but the fire-balls 
seem to be formed not because there is any substance at hand to attract the 
electric matter from the cloud, but because the electricity is accumulated in 
such a quantity that the cloud can no longer contain it. Hence, such balls 
fly off slowly, and have no particular destination; their appearance indicates 
a prodigious commotion and accumulation of electricity in the atmosphere, 
without a proportionable disposition in the earth to receive it. 
From a number of observations, the indefatigable Beccaria also endea¬ 
vours to account for the rising of vapours and the fall of rain, upon electrical 
principles; and, it must be confessed, that if it is not a primary agent in 
these effects, it would be rashness entirely to deny its influence. This phi¬ 
losopher supposes, that previous to rain a quantity of electric matter escapes 
from the earth, and in its ascent to the higher regions of the air collects and 
conducts into its path a great quantity of vapours. The same cause that 
collects will condense them more and more, till in the places of the nearest 
intervals they come almost in contact, so as to form small drops, which, 
uniting with others as they fall, come down in rain. The rain he supposes 
to fall heavier in proportion as the electricity is more vigorous. 
Hail, he supposes to be formed in the higher regions of air, where the 
cold is intense, and where the electric matter is very copious. In these cir¬ 
cumstances, a great number of particles of water are brought near together, 
where they are frozen, and in their descent collect other particles; so that 
the density of the substance of the hail-stone grows less and less from the 
center, this being formed first in the higher regions, and the surface being 
collected in the lower. Agreeably to this, it is observed, that on mountains, 
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