YET 'tis not generally true, that the Wind goes down perpendicular to the Horizon; for often it blows in the Air tranfverfly.

THUS we may fee the Smoke that comes out of a Chimney is not carried by the Wind all one way, but a part of it goes another way.

PROPOSITION XII.

Why the Winds blow with fome Interruption, refling as it were for a Time, and on a fudden return with Force; and why on the Sea they are more conftant.

THE Reason I fuppofe is, that the Cause of the Wind is not conftant, and takes fome time to gather it's Strength; and the Exhalations being more conftant on the Sea, and the Motion of the Wind less hindered; therefore that Change is not fo fenfible there, tho' there is fome Change as to the Degrees of blowing.

PROPOSITION XIII.

Why no Wind blows perpendicularly from the Air or Places of the Earth.

ARISTOTLE, in his fecond Book of Meteors chap. ix. treats very obfcurely of this Question; fo that his Followers do not agree about his Opinion nor fhall I be at Pains to write their Opinions. The Caufe which feems to be more intelligible is, that the Air being thrust down to the Center of the Earth cannot go that way, but is hindered by other Vapours that are forced up; and the great Refiftance of the Air below caufes the Force downwards, to tend fideways: which is the more probable because that which

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the

the Wind confifts of is lighter for the most part than that Air; and alfo more rarified than the Air near the Earth.

PROPOSITION XIV.

Why the Eaft Winds are more frequent than the West.

THE Caufe of this is manifeft from Prop. 10, where we made the Sun the chief Caufe which rarifies the Air from Eaft to Weft; and therefore the Air is more preffed towards the Weft: and this cannot be hindered except there are a great Quantity of Exhalations or Clouds in the weftern Parts, which is not very frequent.

PROPOSITION XV.

Why the North and Eaft Winds are more strong and fevere, and the South and West Winds more weak and gentle.

THE Reafon is because the North Air is groffer on account of the Cold, and the South Air in our Zone is more rarified by the Sun; and the more rarified the Air is, it's Motion is the lefs forcible; yet the South Winds are cold, dry, and ftrong, in the Temperate Zone, contrary to ours, no lefs than the North Winds are to us. But the Eaft Winds are fevere or more intenfe on another Account, viz. that they arife for the most part from the Rarefaction of the Air by the Sun, which is continually carried from Eaft to West, and fo is forced more towards the West. 'tis likely there are other Caufes which hinder or promote this Motion. The Portuguese Sailors call the North and Eaft Wind Bryfas; but the South and Weft they call Vendavales,

But

PRO

PROPOSITION XVI.

Why the South and West Winds are found to be botter. than the Eaft or North, which have a much greater frigorific Power.

THUS is the Question ufually propofed; but we must know 'tis not to be understood generally of all Places, but only thofe in our Zone; for in the other Temperate Zone, towards the South from the Equator, the contrary holds good; for in those Places the North Winds are hot, and the South more cold, and fo the Nature of the Thing requires. For the South Wind being more hot, and the North more cold, proceeds hence that the South Winds come from Places near the Torrid Zone, and the North Winds from the Frigid Zone; but the contrary happens in Places near the Antarctic Pole; for the North Winds come to them from the Torrid Zone, and the South Winds from the Frigid. But another Account is to be given of the Eaft and Weft Winds; for the different Places of the two Temperate Zones are not to be regarded here. First we faid in the preceding Propofition, that the Weft Winds are lefs frequent in all Places; the Caufe of which is the fame with that for which the Weft are found to be hotter; viz. because they blow for the most part in the Night-time after Sun fet, where the Air, preffed to our Place, is hotter or lefs cold than the Air of our Place; as being further from the fetting Sun than the Place between us and the Sun then. There is another Caufe which alfo holds good in the Difference between the North and South Wind; viz. that the Weft Winds do not blow fo strongly, but with fome flowness; for 'tis known that a Gale or Breeze is the colder the more fiercely it blows; tho'

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SECT. VI. tho' it be really in itfelf not colder; as our Breath (which we can make either cold or hot) fhews.

PROPOSITION XVII.

Why Seamen when they see a small black Cloud expect Wind from the Part in which it is, especially if it be of a pale and blackish Colour; and to explain other Signs of the approaching Winds.

A twofold Reason may be given; for either the Clouds of that Colour show that they are soon to be refolved and diffipated into a Wind; or the Clouds falling down by their Weight, prefs the Air below, which caufes a Wind: of that peculiar little Cloud which the Dutch call the Ox-eye, fee the Chapter following.

WHEN the Sun appears spotted, at it's rifing, and hiding itself as it were under a pale or black Cloud, it foretels Showers or Winds to come. 2. If the rifing Sun feem hollow, casting it's Beams as it were from it's middle, it fhews a wet or windy Seafon approaching. 3. If the Sun be of a pale Colour at fetting, it denotes Rain; but if it be of a red Colour, it fhews the next Day will be clear and calm. 4. If the Sun fet pale behind black Clouds it fhews there will be a North Wind foon. 5. If the Moon be red, like Gold, 'tis a fure Sign of a Wind to come, according to the common Verfe

Pallida Luna pluit, rubicunda flat, alba ferenat.

6. A Halo about the Moon; 7. If the Moon's Horns be blackifh, and, 8. If the North Horn of the Moon appear to be more ftretched out, 'tis a Sign of a North Wind; but if the South Horn appear

fo, 'tis a Sign of a South Wind approaching. 9. The rifing of the Moon, and remarkable Stars, as Ar&turus, Orion, and especially the rifing of those in Capricorn, with the Sun. 10. If the two fmall Stars in Cancer, called Afelli, be covered with a Cloud; if the North one, then a South Wind; but if the South one, then a North Wind.

II.

11. The Winds do, for the most part, begin to fettle in a Point, when the Rains are over. 12. A certain Noife and Murmuring; as if there were a Boiling heard in the Sea. 13. The Antients alfo took their Signs from living Creatures; as the Crow, the Goat, the Dolphin, &c. 14. From fiery Meteors, Lightening, and opening of the Ground, and falling Stars; but not that Light feen in the Dark, or Jack with his Lantborn.

PROPOSITION XVIII.

Why the Winds in Spring and Autumn blow more Strongly and frequently, than in the Heat of Summer or Cold of Winter.

I fuppofe 'tis fo in Spring, partly because of the melting of the Snow, especially in high Places; partly because the Pores of the Earth are then open, and fend forth more Exhalations; and partly because the Air and Vapour then becomes more rare; being condensed in the Winter. Moreover, there falls much Rain a Month before the Spring, and in the Spring itself, because the moift Conftellations are in thofe Places of the Zodiac, into which when the Sun enters the Spring begins. But the Caufe of the frequent Rains, and blowing of the Winds in Harvest, is, that the Sun then draws up fome Vapours; but the Heat being fmall, it only draws thofe that are groffer and not fine enough. But in the Summer there are

few