Page:Cyclopaedia, Chambers - Volume 1.djvu/94

 A I R

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A I R

AIR, Aer, in Phyficks, a thin, fluid, tranfparcnt, com- fame may be obferved of Alcohol of Wine, and other full

^rcflible, and dilatable Body ; lurrounding the terraqueous tile and fugitive Spirits, rais'd by Diftillation.— Whetcas real

Globe to a confiderable Height. See Earth, and Ter- Air is not reducible by any Compreflion, Condensation or

raqjieous. the like, into any other Subftance befide A'r. SeejEoLiriLE

Air was confider'd by fome of the Antients as an Ele- Water, then, tho it may put on an aerial Nature tor

menr ; but then, by Element they underftood a different a-while, yet is not capable of perfifting cherein : And the

thing from what we do. See Element. fame may be faid of other Fluids.— The furthefl they can

"fis certain, that Air, taken in the popular Senfe, is far go, is to become Vapour ; which is the Mattet of the Fluid

from the Simplicity of an Elementary Subllance ; tho there render'd much rarer, and put in a brifk Motion. For a

may be fomething in it, which bids fair for the Appellation. Subllance to become permanent Air, it muft be of a fixed

—Hence, Air may be diftinguifh'd into Vulgar, or Hete- Kind: otherwife, it is not capable of undergoing the Alte-

rogeneous ; and "Prefer, or Elementary. ration neceflary to be induced in it ; but gives way and Hies

off too foon. So that the Difference between 'Permanent

Vulgar or Heterogeneous Air, is a Coalition of Corpufcles and Tranfient Air, amounts to the fame as that between

of various Kinds, which together conftitute one fluid Mais, Vapour and Exhalation ; the one, e. g. being dry, the other

wherein we live and move, and which we are continually moift, l$c. See Vapour, and Exhalation. receiving and expelling by Refpiration.— The wholeAffem- We can go a little further yet. — This elaftick Property of

blage of this, makes what we call the Atmofphere. See Air, is fuppofed by many Philofophers, to depend on the

Atmosphere. Figure of its Corpufcles, which they luppofe to be ramous :

Where this Air or Atmofphere terminates, there jEther Some will have 'em fo many minute Floculi, refemblina

is fuppofed to commence ; which is diftinguim'd from Air, Fleeces of Wool 3 others conceive 'em roll'd up like Hoop°

in that it does not make any fenfible Refraction of the Rays and curled like Wires, or Shavings of Wood, or coil'd like the

of Light, which Air does. See .Ether, and Reerac- Springs of Watches ; and endeavouring to ieflore themfelves

tion. in Vittue of their Texture : fo that to produce Air, muft

The Subftances whereof Air confifts, may be reduced to be to produce fuch a Figure and Difpofition of Parts ; and

"two Kinds, viz. 1", The Matter of Light, or Fire, which thofe Bodies only are proper Subjects, which are fufceptible-

is continually flowing into it from the heavenly Bodies. See of fuch Difpofltion ; which, Fluids, from the fmootlinefs

Fire. — To which, probably, may be added the Magnetical roundnefs, and ilippetinefs of their Parts are not. See*

Effluvia of the Earth. See Magnetism. Fluid.

1% Thofe numbetlefs Particles, which in form either of But Sir I. Newton puts the Thing another way • fuch

Vapours, or dry Exhalations, are rais'd from the Earth, a Texture he thinks by no means fufficicnt to account for

Water,^ Minerals, Vegetables, Animals, ige. either by the that vaft Power of Elafticity obferved in Air, which is ca-

folar, fubterrancous, or culinary Fire. See Vapour, and Exhalation

pable of diffufing into above a Million of times more

Space than it before poffefs'd. — But, as all Bodies are fhewn

to have an attractive and a repelling Power j and as both.

Elementary Air, or Air, properly fo call'd, is a certain thefe are flronger in Bodies, the denfer, mote folid and

fubtile, homogeneous, elaftick Matter ; the Balis, or Funda- mental Ingredient of the Atmofpherical Air, and that which gives it the Denomination.

Nature and IProdutfion of Air.

compact they are : Hence it follows, that when by Hea or any other powerful Agent, the attractive Force is fur- mounted, and the Particles of the Body fcparated fo far as to be out of the Sphere of Attraction ; the repelling Power commencing thence, makes 'em recede from e ch other with, a ftrong Force, proportionable to that wherewith they be- The peculiar Nature of this aerial Matter, we know but fore coher'd ; and thus they become permanent Air.-

little of; what Authors have advanced concerning it being chiefly conjectural. We have no way of examining it apart, or feparatjng it ftom the other Matters it is mix'd with 5 and confequently no way of afcertaining with Evidence what belongs to it abftractedly from the reft.

Dr. Hook, and fome others, will have it to be no other than the JEther it felf 5 or that fine, fluid, active Matter, diffufed thro' the whole Expanfe of the Celeftial Regions ; which coincides with Sir Jfaac Newton's Subtile Medium, or Spirit. See^iTHER, Medium, and Spirit.

In this View it is fuppofed a Body fui generis, ingenera- ble, incorruptible, immutable, prefent in all Places, in all Bodies, tyc.

Others, considering only its Property of Elafticity, which they account its effential and conftituent Character ; fup-

Hence, fays the fame Author, it is, that as the Particles cf permanent Air are groffer, and arife from denfer Bodies, than thofe of Tranfient Air, or Vapour : true Air is more ponderous than Vapour ; and a moid Atmofphere lighter than a dry one. Opticks, p. 371, &c. See Attraction, Repulsion, £5?c.

But, after all, there may ftill be Rea r on to doubt, whe- ther the Matter thus produced r rom folid Bodies havo all the Properties of Air ; and whether fuch Air be not tran- fient, as well as that from humid ones ; tho not to that

degree.- Mr. Beyle argues, from an Experiment made

in the Air-Yump with lighted Match ; that thofe light and fubtile Fumes into which the Fire it felf (hatters dry Bo- dies, have no fuch Spring as Air ; fince they were unable to hinder the Expaniion of a litt'e Air, included in a Bladder

pole it mechanically producible ; and to be no other than they futrounded. <Pbyf. Meet. Exper. Yet, in fome

the Matter of other Bodies alter'd, fo as to become per- fubfequcnt Experiments, by diflblvlng Iron either' in Oil of manently elaftick. — Mr. Boyle gives us feveral Experiments, Vitriol and Water, or in Aqua-fortis ; a large aerial Bubble which he made " for the Production of Air; taking Pro- W as produced, which had a real Spting ; fo°as to hinder the " duction for the obtaining a fenfible Quantity thereof, from futrounding Liquor from regaining its Place' and which " Bodies wherein it did not appear either at all, or in fo by the Application of a warm Hand, readily d'ilated it felf

•' great Plenty." Among the feveral Ways of doing this, like other Air, and broke into the Liquor in feveral fuc-

« the fitted for Practice,' he obferves, ' are Fermentation, ceeding Bubbles ; and even thro' the Liquor into the open ' Corrofion, Diflblution, Decompofition ; the boiling of Wa- Air. Ubi fupra.

' ters and other Fluids ; and the mutual Action of Bodies, The fame excellent Perfon further allures us, he procured ' efpecially faline ones, upon each other.' Hifl. of Air. — a really elaftick Subftance from divers other' Matters • as He adds, ' that various folid and mineral Bodies, unfufpect- Bread, Grapes, Muft, Ale, Apples, Peas, Beef gfc. 'and 1 cd of Elafticity, being plunged in corrofive unelaflick from fome Bodies by only burning 'em in Vacuo, particularly ' Menftrua, will, by a proper Comminution of their Parts Paper, Hartfhorn, i$c. which yet, upon further Examina- ' in the Conflict, afford a confiderable Quantity of perma- tion, was fo far from being pure'A'r, that Animals inclofed ' nently elaftick Air.' Ubifupra. in it, not only could not refpire it without harm ; but even

Of the fame Opinion is Sir /. Newton 3 ' The Particles of died fooner than in Vacuo, where there was nothing like
 * denfe, compact, and fixed Subftances, cohering by a ftrong Air. *Pbyf. Mecban, Exper.

<■ attractive Force, are not feparable without a vehement We may here add an Obfervation of the Members of the ' FIcat, or perhaps not without Fermentation ; and fuch Royal Academy of Sciences at 'Paris ; which imports, that ' Bodies being at length rarified by fuch Heat or Fermen- the Property of Elafticity is fo far from conftituting Air ; ' ration, become true permanent Air.' Opticks. — ' Thus, that Air is render'd more elaftick by the Admixture of the fame Author adds, * Gunpouder generates Air by Ex- fome other Matters along with it, than it is in its Purity. — ' plofion.' Ibid. Thus, from fome Experiments of M. de la Hire at 'Paris,

We have hete, therefore, not only the Materials whereof and of M. Stancari at Boulogne, M. Fomenelle affures us, Air (hould be made ; but the Means of doing it : with re- that Air moiften'd with Water, is confiderably more elaftick, gard to which, the Air is divided into Real or %>erma- and expands further, than when pure.— M. de la Hire even tient 5 and Apparent or Tranfient. — For, that all which ap- found the moift Air eight times more elaftick than the dry, pears to be Air does not continue fuch, is evident from Hift. de I'Acad. An. 1708.

the Inftance of an jEolipile ; the Water of which being But it muft not be omitted, that Dr. Jurin explains the fufticiently rarefy'd by the Fire, rufb.es out in a iharp whift- Experiments another way ; ant. endeavours to fhew, that ling Blart, perfectly relembling Air, while the Motion lafls; the Conclufion does not neccftarily follow from 'era. Ap- but foon lofes that tefcmblance, efpecially in the Cold, and find, ad Varen. Geegr. returns by Condcnfation into its original Water ; And the

O Thus