Chapter X

_If in the new Moon._----Rain in the old.

WHEN Exhalations rise copiously from the Earth into the Region of the Air, and the Air itself is in a proper Disposition, they ascend to a great Height, and continue a long Time before they are condensed, which accounts very clearly and philosophically for the Interval of fair Weather between the rising of these Mists, and their falling down again in Showers. Their ascending about Sun-rise is a Proof that the Air is thin, but at the same time of a Force sufficient to sustain them, since if the Mists were not specifically lighter than the Air itself they could not ascend.

WHEN the Moon is at the full, and such Exhalations rise plentifully, the time necessary for them to float in the Atmosphere, before they are condensed into Clouds and Rain, extends, generally speaking, beyond the Period of that Moon, and therefore the Observation directs us to expect _fair Weather_.