phy, well readily agree that there is fuch mixture of an infinite number of different Particles.

SECT. IV. The fame proved in fulphureous Particles.

THAT We may give an imperfect Sketch thereof to fuch as are Ignorant and Unexperienced; and paffing by thofe Effluvia or Vapours that rife from Water, as being too common; that Suphureous Particles are mixed with the Air, may appear from the Scent or Smell of Brimftone that attends Lightning fometimes; befides that, feveral Accounts teach us, that they afcend from the Volcano's or Burning Mountains in vaft Numbers, into which they are diffolved by the means of Subterraneous Fires, after the fame manner as it is done in Chymical Operations: And this is alfo plain from hence, that even here in our Watry. Country, there are Pits or Wells over which if you hold a Candle, the Air will immediately be kindled, infomuch, that whole Houses have been confumed by the firing of fuch Steams; and not long fince, a Perfon was miferably Burnt in that Country which we call the Beemster in North-Holland, which is nothing but a drained Meer or Lake.

SECT. V. The like Mixture with Particles of Fire.

THAT Fire mingles itself with Air, appears by many Experiments, fuch as Lightnings, as also, that Matter which the Chymifts call Phosphorus, which having lain many Years under Water, and being taken out from thence, immediately fhines in the Dark; and with the leaft Warmth (even fo fmall that it can hardly be called hot) it will burn fo, as not to be extinguifh'd. Such a Phofphorus is diftilled from Humane Urine, after it has ftood fo long in the Air till it is corrupted: And fome who have tryed it fay, that in cafe fuch Urine B b 2

can

can be kept where no Air can come at it, notwithstanding it be fo Chymically prepared, it will

neither fhine nor burn.

SECT. VI. Alcali's and Acids mixed with Air.

THAT Volatile and Alcaline Salts, fuch as those that are extracted from Soot, Harts-horn, &c. are diffolved in the Air, is well known to those who have fmelt of the fame, and have often learned to their Coft, that fuch Salts are in no wife to be preferved long; and Glafs Phials filled with these Volatile Saits, and not well stop'd, have frequently been found quite empty, or at least have loft a good Part of them. The fame has been obferved as to Acid Liquors, by the fower Smell that exhales from them, fuch as Vinegar and other things: Infomuch, that if you fet any Acids under a Copper or Brafs Plate, the Vapours that exhale from them, and mingle themselves with Air, will eat through fuch Plates, and turn them into Verdigreafe. Moreover, in diftilling Spirit of Salt-petre, which comes over without any Water, we know that all the Stopples that are used to the Phials that contain 'em, are corroded by the Particles that afcend into the Air; and that the said Spirits being put into an open Bottle, do frequently emit vifible Effluvia.

SECT. VII. Burning Spirits and Oils mix themselves with the Air.

THE Air is likewife impregnated with Burning Spirits. This is known to every Body that has warmed good Brandy, and held a burning Paper or Candle near the Steams of it; of which those that are in the Air are immediately kindled. The fame Experiment is made by the Chymifts in their Distillations, when they try whether their Lutums (that is

the

the Matter which they apply to the Joints of their Veffels) are as close as they should be; for if one holds a Candle to them, and any of the Effluvia come out, thofe that pafs into the Air through the Lutum, will immediately take Fire.

Oils themselves will mingle with the Air. Wherefore, to say nothing of Train-Oil, which can be fmelt fo far off (forafmuch as fome may doubt whether they be the oleaginous Parts themfelves that affect our Noftrils) let any one take Oil of Olives mingled with Salt, and diftil it with a glowing Iron Pot, upon which there is an Iron Helm or Head, with an Orifice or Hole at the Top, fo as it may be fhut with an Iron Cover, he will find when the Cover is taken off, in order to take fome of that Matter with an Iron Ladle out of the Pot, and to put fresh therein, that the Steams (which being drawn over into the Recepient, do there make what they call an Oleum Philofophorum) as soon as they come into the Air, flame out, and fo continue till the Orifice of the Helm be again closed.

SECT. VIII. Other Particles do likewife mix themfelves with Air.

A N infinite Number of other Particles, befides thofe of which we have given Inftances above, are found to incorporate themselves with the Air, as with a common Menftruum or Diffolvent, accordingly it is obferved by Varenius, in his Geography, (Lib. I. Cap. XIX. §.41.) that when the Spices in the Indian Islands are ripe, the Seamen know it by the Smell thereof, at the diftance of three or four Leagues: That in the Iflands named the Azores, the Air is impregnated with so many Acid Particles, that it corrodes even the Iron and Stones of Houses, in fuch a manner, as to reduce them to Duft in a little time: whereas, on the contrary, in the Province

Province of Chili in America, the Air is fo foft, and that tho' one put up a Sword without cleaning it into the Scabbard, there will never be found any Ruft upon it. They that would be further informed upon this Subject, may confult the Author in the place we have quoted.

SECT. IX. Many Particles preferve their Properties in the Air.

AFTER all this, no body I think will scruple to acknowledge the Air to be a Menftruum impregnated with an infinite Number of Particles; only it feems neceffary before we proceed, to fhew, Firft, That the Effluvia of fuch a great Number of folid and fluid Matters, tho' diffolv'd in the Air, may yet preferve the fame Properties which they had before they were mingled therewith. They that defire fufficient Inftances thereof, may fee what that great Naturalift, Mr. Robert Boyle, has writ about them in his Difcourfe on the Nature of Effluviums. This however has been experimentally obferved, firft in fluid Matters from a great many Diftillations of Waters, of Burning Spirits, of Acid Spirits, of Spirits that have Volatile Salts in them, of Quickfilver, and almost all fuch like Liquors, which evaporating in the Air by Warmth, do therein fo very much maintain their own Figure, that being admitted into a Recipient, and turned again into a Liquid Matter, almost all of them yield the fame Fluid of which they were compofed before they were mingled with the Air.

The fame may likewife be obferved in many folid Bodies, which the Chymifts do raise, or (as they phrafe it) fublimate by Fire. Thus, according to the Report of the aforefaid Mr. Boyle, who ought never to be named but with refpect, Sul

phur,

phur, Camphire, Benjoin, Sal-Armoniac, and even a Metal as heavy as Tin, may be fublimed and mix'd with the Air by the Heat of Fire; and the Parts thereof being coagulated by meeting with Glafs or fome other Matter, may be again changed into a folid Body, with the fame Properties it had before.

And let no Man imagine that we draw out this Analogy too far, because they are not fenfible of fuch a Heat, or of fuch Fires in thefe Climates, as might feem fufficient to diffolve thefe Bodies, and to cause them to evaporate into the Air, to perform which, fo intense a Heat is required in Chymistry: For whoever has read any thing concerning the Subterraneous Fires that fhew themfelves in burning Mountains, and with how much Sulphur, Afbes, and other Matters, they have of ten filled the Air, even at the remoteft Places, will find that there is not the leaft room to doubt thereof.

SECT. X. The aforementioned various Particles, by their operating upon each other, cause the Air to be Wholfome or Unwholfome.

FROM what we have fhewn already, it will follow, Secondly, that he who knows how varioufly and powerfully thefe Particles, floating in the Air, do operate upon each other, will eafily conceive, that from the different Conjunctions and Separations thereof, different Qualities of the Air does likewife refult. Infomuch, that fome of the Parts being wholly innocent in their own Nature, by their Conjunction and Mixture with each other, may become hurtful and even fatal; and fo on the contrary, those that are prejudicial, may likewife become healthful, and thus in many Cafes they may undergo many Changes.

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