and the excessive Heat forc'd them to keep their legs naked which became so red and inflam'd that without the greatest Torment they could not endure to set them on the ground In some places of the Country these Soultry Gales last from 9 in the morning till noon which are ready to stifle the inhabitants and blowing immediately from the Scorching Sands the people many times lye in the water to rescue themselves from the intolerable Heats Della Valle says that they are call'd in the Annalls of Persia Bad Semum i. e. Burning and Venemous VVinds. I have heard the like relations from many of our Sea Captains who trade on the Arabian or African Coasts so that I think Mr. Hobs or any other of the Modern Naturallists had little reason to question the Heat of some Winds though in these parts of the world where they travell not over such Sandy Desarts and are more remov'd from the ways of the Sun they are more sensibly Cold. By Gelid Winds I understand those which are colder then our Sensories or the Ambient Air. This Frigidity may happily proceed from the Nitrous particles of which they consist or whatever body else wee reckon to be the Primum Frigidum Or because they have their Origine in those Caverns under the Earth where the Sun beams never penetrate and no Subterraneall warmth is to be found Monsieur De Cartes averrs that all Boistrous Winds from whatever point of the Compasse they blow are Universally Cold and Dry and wee find that any sort of Air violently mov'd by a Fanne or Bellows does refrigerate so that the Cold of Winds may somewhat depend on their motion or manner of affecting our Senses And since the Cartesians will allow Cold to be no positive Quality of it self but a mere Privation of Heat then either the absence of their Subtil matter may cause the Frigidity of Winds or else the occasion thereof must be this that they passe thorough the Gelid Regions which are never visited by the Sun Beams For as Those which come from Aethiopia and other parts of the Torrid Zone doe imbibe the Heat and Sympathise with the nature of the places from whence they come so questionlesse the other that consist of or drive before them the grosse and Frigorifique Air from Groenland and other Northern Climates must needs have considerable allays of the Mediums through which they passe And within the Polar Circles the absence of the Solar rays for so many Months do's sufficiently conduce to the Production of Cold since the Sun which us'd to correct the rigour and inclemency of the weather is now banisht from their Horizon and the Air become Chill and Torpid by the long Predominance of the Cold. So that the VVinds must of necessity admit of very considerable alterations in their passage and whether or no they consist of Frigorifique particles yet by their commerce and enterfering with the Gelid Regions they may draw I know not what Contagion from thence As appear'd in the foremention'd Experiment how much the mixture of Snow and Ice only by applying it to the outside of the bellows did soon infrigidate the Transient VVinds. For I am not sufficiently convinc'd that Cold VVinds proceed always from Nitre Sal Armaniac or other Frigorifique Corpuscles But sometimes only appeare so to us by their particular Motions on our Sensories As wee see any Air Ventilated from Fanns or Bellows or our own breath darted with a very vehement impulse from the Mouth appears Frigid which if wee exhale gaping and in another position of the lips is rather sensibly Hot. Thus if VVinds may be styl'd Cold from a simple Privation of Heat and if only the want of some Subtil Matter the absence of the Sun or other Calorifique Corpuscles will resolve the severall Phaenomena wee commonly ascribe to cold this will be sufficient to constitute the Refrigerative Winds which may better be explain'd in this manner then by the Positive Qualitie of the Peripatetiques or the Nitrous and other Frigorifique particles of the Atomists and Corpuscularian Philosophers I shall only add one circumstance out of the Honourable Mr. Boyl concerning the causes of cold Winds I have supected some Winds may be Cold only by consisting of or driving before them those higher parts of the Air that by reason of the longuid reflexion of the Sun beams in the Upper Region is for the most part Cold. Yet as I before declar'd wee often commensurate the Qualities of Winds not only from their Constituent Particles or their just degrees of Frigidity or Heat but sometimes because they are warmer then the Ambient Air or the Winds that usually blow in such Climats or at leastwise then those membranes or Sensorys by which wee judge them The VVinds which blow off from Sea are farre Hotter then those which come from Land May not the Collucent Salts which create such a sparkling and Coruscation in Tempests or other vehement Collision of the waves be able to produce some heat in the Air and VVinds being either actuall Flames or at least making those impressions on our Sensory's as if they were Neverthelesse since wee find by experience that these kind of Salts with which the Sea water is impregnated doe neither rise up in vapors nor being mingled with liquids any way advance their Heat May there not be other Calorifick Effluviums like the hot Steams in Colepits and Mines that ascend from the bottome of the Sea yet cannot so easily perspire through the solider Superficies of the Earth which renders the Maritime Regions and VVinds hotter then the Midland But whatever be the cause it is most evident that all over Europe the winters are generally milder in Islands then many places in the Continent which lye nearer the Sun As in England then France nay Scotland though it be situate so farre North has seldome more keen and piercing Frosts then Paris or some Citys of Italy which are infested with Terrestriall Winds So likewise part of Asia as in China where it runs to the Southwards of Spain the winters are most excessively cold in the 42 degree of Latitude they have ice which lasts 3 or 4 Months together by reason of the Land Winds For this cause New England though it lyes not so farre distant from the Aequator is incomparably colder then any parts of Great Britain And at Virginia as I have been inform'd the Land Winds oftentimes surprise them with such an Exceding sharp Air that one would think it impossible there should be those extreames of Heat and Cold in the same day So on the Coasts of Carolina and Florida where they have for the most part Midland Winds the Colds are intolerable considering their no great distance from the Sun When as the Sea-Brise in most parts of Europe is temperate and mild I have heard that in the Isle of Jersy the Myrtles will live abroad all winter being cherisht on every side with the tepid vapors from the Sea and
many particles of matter crowded in little Space they must necessarily justle and arietate each other thought VVinds to be nothing else but the Strugling or Agitation of Atoms On the contrary if there chance to be few Atoms in much space so that there be no Pressure or Coarctation in a free spacious heaven this they say begets tranquillity and a serene Temperature of the Heavens Lastly beside this Superoneration these Flatulent Emotions may proceed from any other Cause which alters the Aequilibrium of the Atmosphere So that it will be sufficient to generate Winds if the Air be only denser in one part then another by the unequall distribution of vapours Therefore we have commonly a gentle Brise breathing off from Ponds or Lakes where the Cold more especially condenses the Air at least the Vapours arise in greater plenty from Humid Bodies Thus we sometimes see a larger collection of clouds in one Quarter which being afterwards discharg'd in showrs there oftentimes follows a wind from the immediate conflux of the vapours to that place For the Currents of Air imitate the Motions of water and by the just laws of Hydrostatiques according to their respective gravity mount higher or descend so that there is a perpetuall inquietude till it come to an exact Aequilibrium and what cause soever it be which varys the Counterpoise of the Atmosphere must needs occasion Winds The 2 d cause which produces these Intermediate Winds is Compression when two or more Clouds impetuously pressing or falling upon each other drive out a VVind from between them The Purest most Aetheriall matter is not without some degree of Gravitation though we want Instruments to make such nice discoverys in Nature However the Gosser Vapors Air which inhabite the Middle Region gravitate more sensibly of which wee can be able to give some Account by our Barometers when the Quick silver rises higher or subsides in the Tube VVinds may be thus generated from Pressure alone Suppose D. H. in the following Figure to be the Incumbent Vapors or Clouds F the superficies of the Earth Sea or another subjacent Cloud Wee have a lively resemblance of this in Common Bellows when the Sides closing compresse the included Air force it to issue out impetuously at the Nose or Pipe I have oftentimes observ'd that Stiffe Gusts of Wind happen immediately before Rain because the Clouds being overcharg'd and teeming with showers presse more then at other times and when the Atmosphere begins to thicken and grow Ponderous over our heads wee seldom fail of a VVind some small distance from thence which likewise ceases when the showre is fallen Moreover the Elasticity of the Air which the Peripateticks make little regard of And those Ingenious Moderns who have demonstrated it's Elasticall force from many noble experiments yet never apply'd it Particularly to this Phaenomenon of VVinds though it prove oftentimes the most Immediate cause of their production For the Air whether from the gravity of Incumbent Vapors and Clouds superfluity of matter or however straiten'd and oppres'd do's as soon expand it self like a fleece of Wool after the compression till it arrive at the former Dimensions again And being Dilated Explicated and as it were Unbent must needs agitate and propell the contiguous bodys that reduc'd it to such straits before as we see the Elasticall power of it in VVindguns how impatient it is of restraint and willing to regain it's liberty when the first opportunity is offer'd How easily susceptible of the least impressions as appears from the Propagation of Sounds when the noise of Bells or Canon is heard that is to say they shake the Air for many miles in almost an imperceptible time And the Elastical reciprocations of the Atmosphere by whatever species of coarctation the Aerial spring is bent though they are not obvious to our senses yet are both consonant to reason and agreable to the actings of Nature in such cases And if this strugling or Emotion of the Air necessarily results from it's Elasticity or Repletion This mov'd or agitated Air is Wind Ventus enim est ubi fit agitando percitus Aer Lucret. A 2 d Locall origine of winds in generall is from the Earth or Seas either by resolution of their Superficiall parts or from Submarine or Subterraneall eruptions The Terrheinos or Land Brises between the Tropics which last from the first approaches of Night till Morning consist for the most part of terrestrial Fumes perspiring from no greater depth then the Solar rays did before penetrate And those which alternately blow in the day time are the Ofsprings of the Sea when the Celestial warmth attenuates the liquid Surface into Winds For Humid bodys are soon agitated and Volatilis'd by heat as might appeare from that Vulgar but very considerable Experiment of the Aeolipile by which the strang Sagacity of Art do's so clearly interpret to us the operations of Nature that wee may without difficulty conceive the most forcible emotions of Wind to be generated from the Rarefaction of water Some have us'd them instead of Bellows and contriv'd Pneumatiek Inventions of this Nature to blow the Fire Others have made them large enough to turn the Wheels of spits For the force of the Wind will be greater or lesse Proportionably to the bigness of the Vessel Thus we may Imagine the Atmosphere to be as one Immense Aeolipile continually dilating the Vapors and Air and the Sun likewise to exhale many flatulent steams out of the Marshes and Lakes especially from the Sea which is the most Universall Parent not only of Fountains and Rivers but Winds And though the subtlety of Nature will still exceed the most Accurate Researches of Human wit yet wee have little more to enquire concerning the Naturall then may be advantageously Explicated from the Artificiall Winds Nor doe they only exhale from the Superficies but emerge sometimes from the Gulfs of the Ocean and Profoundest Caverns of the Earth The Earth is the first Mother of Meteors and contains the Principles of them all in her Fruitfull Womb In these Subterraneall Kingdomes are the Spirits Minerals and juyces that afterwards raise Storms by Sea Winds and Thunders in the Air and Earthquakes under Ground Those that have been conversant in Colepits and Mines will frequently predict Tempests from their Damps the burning blew of their candles and other infallible signes From hence these Subterraneall Storms break prison to disturbe the peace of the Atmosphere and raise mutinyes and commotions in the whole body of the Air. My Lord Bacon mentions a rocky and Mountainous place in Wales calld Aber Barry which had many Caverns and recesses under ground where is heard a continuall noise of Winds that resound and tumultuate within And in another place of Denbigh shire there are so vehement eruptions of Wind out of some cavityes and spiracles of the Earth that repell cloths and other injected bodyes and for a great way together dally and play with them
that immense distance from the Earth It would be tedious to recite the dissents of the Greek interpreters with the Latines how many nauseating and frivolous contests arose upon this Argument between Theophrastus Aphrodisaeus the School of Alexandria and in the more flourishing raign of Peripatetisme how strangely did Albertus Magnus Thomas Aquinas Cajetan and Contarenus with many others of the Seraphic and Angelicall Doctors torture their wits either to find out some new Salvo for the Hypothesis of Aristotle or invent a worse of their own Bonaventure writ a whole book wherein he treats of little else beside the severall opinions concerning the Transverse motion of Wind. And we must needs esteeme it a great effect of their leisure who have employd so much time in such empty and jejune speculations Yet not only the Peripatetiques have fail'd in their attempts but we have as little satisfaction from Epicurus or the severe Porch may as justly question whether the Theories which shall be started hereafter must hope for any better successe Yet I think wee may thus farr rationally conclude that as the causes of Winds are various so the reason of their Transverse Motions is not always one and the same I have frequently observed that not only the North but most other Winds seem many times rather somewhat to descend then blow in an exact Perpendicular line to the Horizon yet wee must acknowledge that even those which relapse from the Middle Region or are generated by the Rarefaction of Vapors in the Intermediate space between the Earth and Clouds have for the most part an oblique or Semicircular Motion for though their Ingenit weight would rather Praecipitate them to the Earth yet they are either born up and repel'd by the continuall Effluxions of ascending Steams or at least can descend no lower then where they come to the just counterpoise of the Air. So that if the Flatulent Vapors have gravity enough especially after they are Condens'd in the Colder Region to invite them Downward and yet the resistence of the Atmosphere sufficient in a great measure to check and retard their descent this must necessarily divert them from their Precipice inclining them rather to a mixt and Collaterall Motion For though Winds are generally heavyer then the Air below yet they are supported in it during their Career till by degrees falling downwards to the Earth they at length cease or languish in their Course Wee must note likewise that the whole body of the Air settles about the Earth in a sphericall Figure so that the protrusion is made from all parts to the Center that the Winds being resisted by the Pressure of the Atmosphere above and the Earth or Sea below move as in a Channell between both wherefore they soare highest in a Serene Skye when the depression of the Air and Winds is much lesse then in Cloudy weather And the reason why they blow Obliquely or which is all one perpendicularly to the Horizon is not to be suppos'd because the Vapors are naturally determin'd to any such particular species of Agitation but that being dilated by the Sun they require a larger space and find the Medium most dispos'd to admit of their Motions in that manner Lastly those VVinds which emerge from the Caverns under Ground may sometimes have that Tranverse Motion impres'd on them from their Fountains at the time of their Eruption For those Volatile spirits or Salts being once mov'd in the Hollows of the Earth by the Subterraneall warmth are still roving up and down and restlesse till they get vent and after their release protrude the Contiguous Air and propagate the same kind of Agitation in whatever bodys occurre in the way and then all Auxiliary Vapors will be sure to have Immediate recourse whither the strongest current bends But beside these Primitive and Originall there are other Secundary causes and Affections of VVinds as their Undulation Repercussion from Promontorys Opposition c. VVee have thus farre enquir'd into the Progressive but the Undulating Motions are no lesse considerable in VVinds for they blow not in one constant fluor or streame but in gusts that have their starts and intervals intermitting like our pulse which is call'd the Undulation of VVind or Air from the resemblance it bears to the wavings and fluctuation of VVaters Some of them are Indigenae or Natives and others Adventitious to the places where they blow yet the question still recurrs for those which are Externs and either come from beyond Sea or rove from farre countrys have the same Locall Origine with the rest though remoter from our observation The motions of VVinds as indeed all other bodys whatever are propagated in right lines if nothing intervene to check and retard their course but usually so many impediments occurre that are able to make resistence in the way that they seldome proceed in one uninterrupted Perpendicular from their fountains Especially in moutanous places Forrests and other Eminencys and inequalitys of Ground but they are repuls'd and recoyl back again and being sometimes imprison'd in the straits or Creeks of promontorys they are tost and banded to and fro like Tennis balls till they find their passage out so that after severall diversions it may happen at last that a VVind may bee distracted to a quite different point of the compasse and otherwhile so far befreinded by the advantageous situations of the places where they blow that they run streaming between two Mountains as in a Channell or trough and are guarded on all sides from the inroads of other Exotique VVinds and Air. Upon this account it s no very unusuall thing to have one VVind blow on the Top of a Mountain and a quite contrary in the Vally below In the main Sea they keep the same quarter a long time when nothing occurrs that can controle them but neer mountainous Islands or shoares they whiffle up and down and shift from one point of the Compasse to another by severall repercussions from the promontorys or hills and these our Seamen call Eddy Winds For as Water once dismis'd from the Fountains head is not only tinctur'd with the qualities it receiv'd from thence but must afterwards conform to the course of the Channell or banks through which it glides so the VVinds which are Torrents or Rivulets of Air have their Maeanders and deflections in their Journy and are in a great measure obnoxious to the situation of the Country 's in which they blow They also meet with frequent opposition from the repletion of the Atmosphere with multitudes of fresh Exhalations that check and crosse them in their way but especially by their Rancounters with Contrary Winds which must necessarily Engage and strive for mastery till one overcomes So that from two contrary VVinds there sometimes results a Third compounded of both Extremes and otherwhile if they meet in the Eye of each other from Diametrically opposite points of the Compasse they ballance one another and there ensues a calme