CHA P. II.

Of the Winds (a).

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O pafs by other Confiderations, whereby I might demonftrate the Winds to be the infinite Creator's Contrivance, I fhall infift only upon their great usefulness to the World. And fo great is their Ufe, and of fuch abfolute Neceffity are they to the Salubrity of the Atmosphere, that all the World would be poifoned without those Agitations thereof. We find how putrid, fetid, and unfit for Respiration,

(a) Ventus eft aer fluens, is Seneca's Definition, Na. Qu. 1. 5. And as Wind is a Current of the Air, fo that which excites or alters its Currents may be justly faid to be the Caufe of the Winds. An Equipoife of the Atmosphere produceth a Calm; but if that Equipoife be more or lefs taken off, a Stream of Air, or Wind, is thereby accordingly produced either ftronger or weaker, fwifter or flower. And divers things there are that may make fuch Alterations in the Equipoife or Balance of the Atmosphere, viz. Eruptions of Vapours from Sea or Land; Rarefactions and Condensations in one Place more than another; the falling of Rain, preffure of the Clouds, c. Pliny, 1. 2. c. 45. tells us of a certain Cavern in Dalmatia, called Senta, in quem, faith he, dejecto levi pondere, quamvis tranquillo die, turbini fimilis emicat procella. But as to Caves it is obferved, that they often emit Winds more or less. Dr. Connor, taking notice of this matter, specifies thefe, In regno Neapolitano ex immani Cumana Sibylla antro tenuem ventum efflueutem percepi. The like he obferved at the Caves at Baia, and in fome of the Mines of Germany, and in the large Salt-Mines of Cracow in Poland. Ubi, faith he, opifices, & ipfe fodina dominus Andreas Morftin, Nob. Polonus, mihi afferuerunt, quòd tanta aliquando Ventorum tempeftas ex ambagiofis hujus fodina receffibus furgere folebat, quod laborantes foffores humi profternebat, nec non portas & domici lia (qua fibi in hac fodina artifices exftruunt) penitùs evertebat. Bern. Connor. Differt. Med. Phyf. p. 33. Artic. 3.

And as great Caves, fo great Lakes fometimes fend forth Winds. So Gaffendus faith the Lacus Legnius doth, E quo dum exoritur fumus, nubes hand dubiè creanda eft, que fit brevi in tempeftatem

Refpiration, as well as Health and Pleasure, a ftagnating, confined, pent up Air is. And if the whole Mafs of Air and Vapours was always at Reft, and without Motion, inftead of refreshing and animating, it would fuffocate and poifon all the World:

But

tempeftatem faviffimam exoneranda. Gaffend. Vit. Peiresk. 1. 5.

P. 417.

But the most univerfal and conftant Alterations of the Balance of the Atmosphere are from Heat and Cold. This is manifeft in the General Trade-Winds, blowing all the Year between the Tropicks from East to Weft: if the Cause thereof be (as fome ingenious Men imagine) the Sun's daily Progrefs round that part of the Globe, and by his Heat rarefying one part of the Air, whilft the cooler and heavier Air behind preffeth after. So the Sea and Land Breezes in Note d. And fo in our Climate, the Northerly and Southerly Winds (commonly esteemed the Caufes of cold and warm Weather), are really the Effects of the Cold or Warmth of the Atmofphere Of which I have had so many Confirmations, that I have no doubt of it. As for Inftance, it is not uncommon to fee a warm Southerly Wind, fuddenly changed to the North, by the fall of Snow or Hail; to fee the Wind in a frofty, cold Morning North, and when the Sun hath well warmed the Earth and Air, you may observe it to wheel about towards the Southerly Quarters; and again to turn Northerly or Eafterly in the cold Evening. It is from hence also, that in Thunder-Showers the Wind and Clouds are oftentimes contrary to one another, (especially if Hail falls) the fultry Weather below directing the Wind one way; and the Cold above the Clouds another way. I took Notice upon March the 10th 171, (and divers fuch like Inftances I have had before and fince) that the Morning was warm, and what Wind flirred was Weft-South-Weft, but the Clouds were thick and black (as generally they are when Snow ensues): A little betore Noon the Wind veered about to North by Weft, and fometimes to other Points, the Clouds at the fame time flying fome North by Weft, fome South-Weft: About one of the Clock it rained apace, the Clouds flying fometimes NorthEaft, then North, and at last both Wind and Clouds fettled North by Weft, At which time Sleet fell plentifully, and it grew very cold. From all which I obferve, 1. That although our Region below was warm, the Region of the Clouds was cold, as the black, fnowy Clouds fhewed. 2. That

the

But the perpetual Commotions it receives from the Gales and Storms, keep it pure and healthful (b).

Neither are thofe Ventilations beneficial only to the Health, but to the Pleasure alfo of the Inhabitants of the Terraqueous Globe; witnefs the Gales which fan us in the heat of Summer; without which, even in this our temperate Zone, Men are fcarce able to perform the Labours of their Calling,

or

the ftruggle between the warmth of ours, and the cold of the cloudy Region, ftopped the airy Currents of both Regions. 3. That the falling of the Snow through our warmer Air melted into Rain at firft; but that it became Sleet after the fuperiour Cold had conquered the inferiour Warmth. 4. That, as that Cold prevailed by Degrees, fo by Degrees it wheeled about both the Winds and Clouds from the Northwards towards the South.

Hippocrates, 1. 2. De Vict. Orat. Omnes Ventos vel à nive, glacie, vehementi gelu, fluminibus, &c. fpirare neceffe judicat, Bartholin. de ufu Nivis, c. I.

(b) It is well obferved in my Lord Howard's Voyage to Conftantinople, that at Vienna they have frequent Winds, which if they ceafe long in Summer, the Plague often enfues: So that it is now grown into a Proverb, that if Auftria be not windy, it is fubject to Contagion. Bohun of Wind, p. 213.

From fome fuch Commotions of the Air I imagine it is, that at Grand Cairo the Plague immediately ceafes, as foon as the Nile begins to overflow; although Mr. Boyl attributes it to nitrous Corpufcles. Determ. Nat. of Effluv. Chap. 4.

Nulla enim propemodum regio eft, qua non habeat aliquem flatum ex fe nafcentem, & circa fe cadentem.

Inter catera itaq; Providentia opera, hoc quoq; aliquis, ut dignum admiratione fufpexerit. Non enim ex una causâ Ventos aut invenit, aut per diverfa difpofuit: fed primum ut aera non finerent pigrefcere, fed affiduâ vexatione utilem redderent, vitalemq; tračturis. Sen. Nat. Quæft. 1. 5. c. 17, 18.

All this is more evidènt, from the Cause affigned to malignant epidemical Difeafes, particularly the Plague, by my ingenious, learned Friend, Dr. Mead; and that is, an hot and moift Temperament of the Air, which is obferved by Hippocrates, Galen, and the general Hiftories of Epidemical Difeafes, to attend thofe Diftempers. Vid. Mead of Poisons, Effay 5. p. 161. But indeed, whether the Caufe be this, or poifonous, malignant Exhalations or Animalcules, as others think,

the

or not without Danger of Health and Life (c). But especially, witnels the perpetual Gales which throughout the whole Year do fan the Torrid Zone, and make that Climate an healthful and pleasant Habitation,

the Winds are however very falutiferous in fuch Cafes, in cooling the Air, and difperfing and driving away the moist or peftiferous Vapours.

(c) July 8. 1707, (called for fome time after the Hot Tuef day,) was fo exceffively hot and fuffocating, by reafon there was no Wind ftirring, that divers Perfons died, or were in great Danger of Death, in their Harveft-Work. Particularly one who had formerly been my Servant, a healthy, lufty, young Man, was killed by the Heat: And feveral Horfes on the Road dropped down and died the fame Day. . In the foregoing Notes, having Notice of fome Things relating to Heat, although it be fomewhat out of the way, I hope the Reader will excufe me, if I entertain him with fome Obfervations I made about the Heat of the Air under the Line, compared with the Heat of our Bodies. J. Patrick, who, as he is very accurate in making Barometrical and Ther mometrical Inftruments, had the Curiofity for the nicer adjufting his Thermometers, to fend two abroad under the Care of two very fenfible, ingenious Men; one to the Northern Lat. of 81; the other to the Parts under the Equinoctial: In thefe two different Climates, the Places were marked where the Spirits flood at the feverest Cold and greatest Heat. And according to thefe Obfervations he graduates his Thermome ters. With his Standard I compared my Standard Thermometer, from all the Degrees of Cold, I could make with Sal Armoniack, &c. to the greatest Degrees of Heat our Thermometers would reach to. And with the fame Thermometer (of mine) I experimented the greatest Heat of my Body, in July 1709. First in an hot Day without Exercife, by putting the Ball of my Thermometer under my Armpits, and other hottest Parts of my Body. By which means the Spirits were raised 284 Tenths of an Inch above the Ball. After that, in a much hotter Day, and indeed nearly as hot as any Day with us, and after I had heated my my felf with strong Exercife too, as much as I could well bear, I again tried the fame Experiment, but could not get the Spirits above 288 Tenths; which I thought an inconfiderable Difference, for fo feemingly a very different Heat of my Body. But from fome Experiments I have made (altho' I have unfortunately forgot

C

Habitation, which would otherwise be scarce habi

table.

To thefe I might add many other great Conveniencies of the Winds in various Engines, and various Businesses. I might particularly infift upon its great Use to tranfport Men to the fartheft diftant Regions of the World (d) and I might particularly speak of the general and coafting Trade-Winds, the Sea, and the Land-Breezes; (e) the one ferving to carry the Mariner in long Voyages from Eaft to Weft; the other ferving to waft him to particular Places;

ten them) in very cold Weather, I imagine the Heat of an healthy Body to be always much the fame in the warmest Parts thereof, both in Summer and Winter. Now between those very Degrees of 284 and 288, the Point of the equatorial' Heat falleth. From which Obfervation it appears, that there is pretty nearly an equal Contemperament of the Warmth of our Bodies, to that of the hotteft Part of the Atmosphere inhabited by us.

If the Proportion of the Degrees of Heat be defired from the Freezing-Point, to the Winter, Spring, and Summer Air, the Heat of Man's Body, of heated Water, melted Metals, and fo to actual Fire; an Account may be met with of it, by my moft ingenious Friend, the great Sir Ifaac Newton, in Phil. Tranfact. No. 270.

(d) In hoc Providentia ac Difpofitor ille Mundi Deus, aera ventis exercendum dedit, non ut nos claffes partem freti occupaturas compleremus milite armato, &c. Dedit ille ventos ad cuftodiendam cœli terrarumq; temperiem, ad evocandas fupprimendáfq; aquas, ad alendos fatorum atq; arborum fructus; quos ad maturitatem cum aliis caufis adducit ipfa jactatio, attrahens cibum in fumma, & ne torpeat, promovens. Dedit ventos ad ulteriora nofcenda: fuiffet enim imperitum animal, & fine magnâ experientia rerum Homo, fi circumfcriberetur natalis foli fine. Dedit ventos ut commoda cujufq; regionis fierent communia; non ut legiones equitemq; geftarent, nec ut perniciofa gentibus arma tranfveberent. Seneca, ibid.

(e) Sea-Breezes commonly rife in the Morning about nine a Clock. They first approach the Shore gently, as if they were afraid to come near it. It comes in a fine, small, black Curle upon the Water, whereas all the Sea between it and the Shore (not yet reached by it) is as smooth and even as Glass is

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