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or containing it in a less proportion than themselves. This, in all proba¬ 
bility, is frequently the case with those vapours or clouds which are pro¬ 
duced by exhalations from the earth, from fresh water, and the perspiration 
of plants and trees; at least it is an undoubted fact, that some clouds (to use 
the language of this branch of philosophy) are electrified positively, and 
others negatively. No sooner does a communication take place, but the 
repulsion between the particles of water is diminished, those which have dis¬ 
charged part of their electricity are successively attracted by the contiguous 
ones which have not, and thus they press nearer together, become speci¬ 
fically heavier than the atmosphere, and descend in small drops, which, 
losing every instant more and more of the electric fire, coalesce? uniting into 
larger and larger drops, and consequently filling a space which is continually 
diminishing, as they approach nearer to the surface of the earth. This may 
be illustrated by electrifying the stream of a fountain, which will spread itself 
into the form of a brush by the mutual recession of the particles of water: 
but withdraw the supply of electric fire, and the fountain discharges itself in 
one continued current.* A pair of cork balls suspended together by silken 
threads, when electrified recede from each other, and if the air be dry, return 
by degrees only to their natural position. Two feathers electrified will float 
in the atmosphere, mutually repelling each other, when in a certain degree 
of contiguity, and gradually descending as they lose that power, which by 
expanding their plumulce, rendered them specifically lighter than the air. 
But if one of them discharges suddenly the electric fire, it will instantly be 
attracted towards the other, and receive a fresh supply; when a repulsion 
(acting indeed at a much less distance than before) will again take place be¬ 
tween them. 
When two clouds, one replete with electric fire, the other destitute of it, 
come within the sphere of each other’s attraction, they will rush together, 
and the electrical fluid being diffused through a larger space, the particles of 
water will unite, and form themselves into drops of greater magnitude, and 
a heavy shower will be produced. Still however as the rain descends 
through an atmosphere containing little electric fire, it will be continually 
communicating it, and thp discharge being greatest from the circumference 
of the cloud, because the surface is there largest, the drops will be drawn 
* Yide Note page 1 67 * 
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