_That nothing which moves upon the Surface of the Earth, is so swift as
the Wind._
Though, in a Storm, Wind moves with a great Velocity, yet in a moderate
Gale, it is nothing near so swift as is generally apprehended.
The Ancients were so wrapped up in their Opinion of the Swiftness of Wind,
that they were sure to introduce it as a Simile, when they intended to
describe any Thing that was rapid in it's Motion.
Horace, for one, was so fond of it, that he has introduced it into his
elegant Ode, _Otium Divos_, &c.
_Scandit æratas vitiosa Naves,_
_Cura; nec Turmas Equitum relinquit_
_Ocyor Cervis et agente Nymbos_
_Ocyor Euro._
However, one would think, that if he was determined to compare Wind to an
Idea or Sensation in the human Mind, he might have thought of one more
swift in it's Motions. For though the East Wind is a heavy Wind, and lays
very keen Hold of a Sail, as being cold, and therefore more condensed, and
moving with greater Moment, on Account of it's Weight; yet I am very much
mistaken if we have any East Winds, that travel near so fast as the
South-West Winds which we have in March; nay, so far is it from being
swift, that when it is set in, we may feel it blow against our Bodies, with
a more steady, slow Motion than any other; and it is reasonable to suppose,
that it ought to move slower according to the Rules of Philosophy: For the
Barometer shews, that the colder the Air is, the more it weighs; and a
heavy Body takes more Time in changing it's Place, by a Force or Cause,
than a light one.
However, we will not tax Horace with Impropriety, in so fine an Ode; as we
do not know, what the East Winds may be in Italy. They had not the German
Ocean to pass over, before they came to Horace, and may be warm, light, and
soft, in that Country.
But to return: There are many Things upon the Surface of the Earth,
(without being obliged to have Recourse to the extraordinary Velocity of
Light) which move faster than the Wind. We have no Occasion to go any
further than the Flight of a Pigeon, or a Swallow, even for a Storm; which
we may observe, by the Motion of light Bodies, such as Feathers and Straws,
which have no Power to resist it's Force, and must be hurried away with the
same Velocity as the Wind itself. We may easily try the Experiment, by
throwing Feathers from off a Church Steeple, or any high Place; and we
shall find, that though they will be hurried off at a great Rate, yet not
so swift as a Pigeon upon her full Stretch. Those who are at Sea have a
much better Opportunity of observing it's Motions than Landmen: Nothing is
more common, than to see that the Wind has chopped about, by it's Action
upon the Sails of a Ship at great Distance off; and it is a long Time
before it reaches the Sails of the Ship from whence it is first discovered;
and even when a Storm is seen coming at a Distance, they have Time enough
to reeve the Sails, and lie in a Posture to receive it. It would be very
easy at Land, to take an exact Measure of the Velocity of any Wind, by
watching it when it first comes. It might be done in this Manner, viz. by
taking the exact Distance of all the Churches in the Neighbourhood from
each other, and setting Flags upon the Steeples of those which stand easy
to be seen, and which are in different Directions; after which, a Person
might go up to the Top of one which stood in the middle of them, with a
Telescope, and as soon as he saw the Flags upon any of the Steeples at a
Distance move from the Directions which they stood in when he first
ascended the Steeple, he might be certain of a fresh Gale being come, and
that it had just then reached that Steeple. Upon seeing this, all that he
would have to do would be, to look at his Watch and by that Means he would
know how fast the Gale of Wind had travelled, by observing how many Miles
it had gone in such a Time. For by observing the Flag on the Steeple at a
Distance, he might know when it had reached that Place, and by the Flag
upon the Steeple where the Observer himself stood, he might see when it
reached him, and by his Watch he might know how long it had been coming.
* * * * *