2. An electrified body left in a room for some time, will be more covered with dust than other bodies in the same room not electrified, which dust seems to be attracted from the circumambient air.
Now we know that the rain, even in our hottest days, comes from a very cold region. Its falling sometimes in the form of ice, shows this clearly; and perhaps even the rain is snow or ice, when it first moves downwards, though thawed in falling: and we know that the drops of rain are often electrified: but those causes of addition to each drop of water, or piece of hail, one would think could not long continue to produce the same effect; since the air, through which the drops fall, must soon be stripped of its previously dissolved water, so as to be no longer capable of augmenting them. Indeed very heavy showers, of either, are never of long continuance; but moderate rains often continue so long as to puzzle this hypothesis: so that upon the whole I think, as I intimated before, that we are yet hardly ripe for making one. ****
B. FRANKLIN.
FOOTNOTE:
[25] This letter is taken from the Memoirs of the Literary and Philosophical Society of Manchester, Vol. II. page 126. It was communicated by the person to whom it is addressed, and was read in the Society, January 21, 1784, as an appendix to a paper by Dr. Percival on the same subject. Editor.
TO MR. NAIRNE, OF LONDON[26].
[Proposing a slowly sensible Hygrometer for certain Purposes.]
Passy, near Paris, Nov. 13, 1780.
Sir,