Meteorology By Aristotle

But this involves the view that lightning actually is prior to thunder
and does not merely appear to be so. Again, this intercepting of the
fire is impossible on either theory, but especially it is said to
be drawn down from the upper ether. Some reason ought to be given
why that which naturally ascends should descend, and why it should
not always do so, but only when it is cloudy. When the sky is clear
there is no lightning: to say that there is, is altogether wanton.

The view that the heat of the sun's rays intercepted in the clouds
is the cause of these phenomena is equally unattractive: this, too,
is a most careless explanation. Thunder, lightning, and the rest must
have a separate and determinate cause assigned to them on which they
ensue. But this theory does nothing of the sort. It is like supposing
that water, snow, and hail existed all along and were produced when
the time came and not generated at all, as if the atmosphere brought
each to hand out of its stock from time to time. They are concretions
in the same way as thunder and lightning are discretions, so that
if it is true of either that they are not generated but pre-exist,
the same must be true of the other. Again, how can any distinction
be made about the intercepting between this case and that of interception
in denser substances such as water? Water, too, is heated by the sun
and by fire: yet when it contracts again and grows cold and freezes
no such ejection as they describe occurs, though it ought on their
the. to take place on a proportionate scale. Boiling is due to the
exhalation generated by fire: but it is impossible for it to exist
in the water beforehand; and besides they call the noise 'hissing',
not 'boiling'. But hissing is really boiling on a small scale: for
when that which is brought into contact with moisture and is in process
of being extinguished gets the better of it, then it boils and makes
the noise in question. Some-Cleidemus is one of them-say that lightning
is nothing objective but merely an appearance. They compare it to
what happens when you strike the sea with a rod by night and the water
is seen to shine. They say that the moisture in the cloud is beaten
about in the same way, and that lightning is the appearance of brightness
that ensues.