or a certain Number of Days, then it follows, that
if these can be determined with Certainty, the Time of their blowing
may also be determined, at least with great Probability, which is as
satisfactory an Answer as can be justly expected, because it shews that
there is just and rational Ground for confiding in such Observations,
when confirmed by long Experience.

XVII.

_Fair Weather for a Week, with a Southern Wind, is like to_
produce a great Drought, _if there has been much Rain out of the
South before. The Wind usually turns from North to South, with a quiet
Wind without Rain, but returns to the North, with a strong Wind and
Rain; the strongest Winds are when it turns from South, to North by
West._

N. B. _When the North Wind first clears the Air (which is usually
once a Week) be sure of a fair Day or two._

OBSERVATIONS of this Nature upon Winds have employed the ablest Heads
in all Ages. _Pliny_ the great Naturalist has left us a great deal upon
this Subject, which plainly proves that it has been the Opinion of the
ablest and wisest Men that Study and Experience might reduce even
Things of such seeming Incertainty under stated Rules, and within the
Bounds of a regular System. For Instance he tells us.

"IN _Africa_ the South Wind is serene, the North East cloudy.
All the Winds have their Turns. To judge rationally of their
Changes, the fourth Day of the Moon is to be regarded.--The South
Wind blows stronger than the North East, because the former rises
from the Bottom, whereas the latter comes from the Surface of the
Sea. It is for this Reason that those Earthquakes are most
dangerous that follow after a South Wind."

IN order to understand this Notion of _Pliny_, we need only advert
to the Account given us by the Reverend Mr. _Robinson_, in his
natural History of _Westmoreland_, which is exceedingly curious,
and well worthy of the Reader's perusal. This ingenious Gentleman is of
Opinion that Winds have their original from the Sea, of which he gives
the following very probable Account.

"IT, that is, the Wind, proceeds from vast swarms of nitrous
Particles arising from the Bottom of the Sea, which being put into
Motion, either by the central Fire, or by the Heat and Fermentation
which abound in this great Body of the Earth; and therefore the
first Commotion excited by the said Fermentation, we call a _Bottom
Wind_, which is presently discovered by Por