SECT. XIX. An Experiment to prove that Mifts and Fogs may be produced by Effervefcences.

Thirdly, Another manner by which the Air may be render'd Foggy, will appear by an Experiment made with two little Glaffes or Phials containing an Ounce each; one of which being almost filled with Spirit of Salt-Petre, or Aquafortis, or elfe with Spirit of common Salt, and t'other with that of Sal Armoniac; put the Mouths of both the Bottles near to each other, and you will find, that the Exhalations of both being mingled in the Air, will produce a vifible Smoak or Mift, which, if the Bottles be placed far enough afunder, cannot be obferved in either of them.

Now that this way of Effervefcence, as the Chymifts call it, is brought about by the reciprocal Action of their Particles in the Air, will be readily allowed by any one that ever faw the Effervefcence or Fermentation that is caufed by pouring one of thefe Liquors upon the other.

SECT. XX. An Experiment proving the like Effect by Precipitations or Separations.

Fourthly, We learn another way from Chymistry of turning clear and tranfparent Liquors oftentimes into a thick and troubled Matter, by Separation or Precipitation: Thus Sublimate or Vitriol diffolved in Water, and filtrated thro' a Paper, does yield a clear Liquor; but pour into it either Salt of Tartar or Potash, likewife diluted in Water, both of which are tranfparent, and you will prefently fee fome Parts of the firft Liquor precipitated or feparated from the reft; by which means the Liquors will lofe their Clearnefs, and be changed into a dark and thick Subftance.

Whe

Whether this has alfo place in fome of those that People call Stinking Fogs, I fhall not enquire any farther here: this is certain, that thofe Stenches have often a great affinity with that which we discover in making Milk of Sulphur, or the Golden Sulphur from Antimony.

To prepare the laft, they ufe to boil in Water the Sulphur of the Regulus of Antimony mingled with Salt of Tartar in the Fire, and to filtrate the fame thro' a Paper, fo that there proceeds from it a clear Liquor of a reddifh Colour, and without any Smell; but putting in fome drops of Vinegar, a grievous Stench arifes from it, and the Liquors become thick and untransparent; until there fubfides from it an Orange Colour and Yellowifi Powder, which is the Golden Powder, and then both the Liquors become clear again.

I have often thought with my felf, whether there were not fomething like this in the Air, which by way of Precipitation might produce thofe Stinking Fogs; Firft, by reafon of the likenefs of the Scent; and Secondly, becaufe I have oftentimes obferv'd, upon the Days fucceeding thefe Fogs, a Reddifh or Ornage Colour Scum, very like that of the above-mention'd Golden Sulphur, upon Standing Waters; which before those Fogs happen'd, were not to be found there. But I leave all this to further Enquiries.

SECT. XXI. Fogs are Clouds.

AFTER having treated of Foggy and Misty Airs, it does not feem neceffary to fay any thing more about Clouds; because it is very credible, that what we call here below Mifts and Fogs, when raised up higher in the Air, do compofe the Matter of Clouds; infomuch that a Cloud is nothing but an exalted Fog; now that this is fomeCc 2 thing

thing more than a bare Suppofition, appears from Experimental Trials made by many People, who having climbed up high Mountains, met with thick Fogs in their way; but when they were arrived to the Top, they observed the fame floating under them like great and white Clouds. Varenus gives us a particular Relation thereof in his Geography, Lib. I. cap. 19. § 41.

The fame is afferted by that great Examiner of Nature, Mr. Mariotte, in his Difcourfe Du Movement des Eaux, p. 19. That climbling up a Mountain, at one place he was in the middle of a Fog, which whilft he was below at the Foot of the fame Mountain, appear'dto him like a Cloud.

Another common Experiment may be made, when Gunners are trying their Cannon, by difcharging feveral Pieces at once: Now every one knows that the Smoak thereof feems to those that are under it like a Mist in the Air; and fo it appeared to me and others that were in the Boat with me, between Amfterdam and Buikslot, like a black Cloud driving foftly on; especially, after it was carried by a gentle Wind, that did not fcatter it, to a good distance from the place where it was discharged, and raifed up higher in the Air. So that likewife it feems deducible from hence, that it is not always Watry Vapours, but also other Particles and Exhalations of which the Clouds are compofed: Concerning which, as alfo of the Rains and Dews proceeding from the fame, and other Meteors properly belonging to Water, fomething more fubfervient to our Defign fhall be mention'd hereafter in our Contemplation upon Water. To proceed.

SECT.

SECT. XXII. Wind and its Usefulness, and ConviEtions from thence.

A MONG the most common, but not the leaft wonderful Motions of the Air, Wind has the principal place. Now it is known to every one, that the Wind is a flood or a ftream of mov'd Air, infomuch that it wants no farther Proof after fo many Experiments, only let us obferve here firft in general, that it is fomething, which after a very fublime manner, fhews the Power and Goodness of the Great Creator.

They that have ever read of, or tried the dreadful Force of Storms and Tempefts, of Hurricanes and Travadoes, will be fufficiently convinced of the Refiftless Power of the Wind. But Cuftom makes us contemplate this great Wonder without any Emotion. But if there fhould be ftiil any one fo wretched as not to learn his Obligations of Thankfulness to the Great Giver of all Things from these his Works, let him for once fuppofe with us, that there was no fuch thing in the World as Wind or Motion of Air, but that it remained in a perpetual Stagnation quite round the Globe, like a Pond or Lake of thin and dead Water. Muft he not then own;

Firft, In cafe that what was raifed up in the Air fhould remain in the fame place, without being carried elsewhere, or fo long at leaft, till it grew lighter, and so afcended, or heavier, and then defcended; (to fay nothing of Cities and Countries, which after Earthquakes might be vifited with fad and fatal Diftempers, by the Corruption of the Air) that great Trading Towns and Populous Places, where the Smoak of fo many Fires of Coal, Turf or Wood, the Vapours offo many ftagnating Waters, the Stench of fo many impure

Cc3

Places,

Places, and thousands of other kinds of Exhalations proceeding from Men, Beafts &c. did continually and inceflantly fill the Air; and the whole World too, would foon be one univerfal Church-yard and Burying-place; for all its Inhabitants wou'd foon perifh, were it not that by the help of thefe Winds, fo exceeding neceffary towards the fupport of all Living Creatures, fresh Air is continually derived to them from the Hills, and other healthy Places round about them; and the unwholfome and infectious Vapours driven from thence, and diffipated in the vaft fpace of the Skies. And can he that obferves all this, perfwade himself to believe that Winds are meerly accidental, and that he owes no Thanks for this great Benefit to him that made the Winds?

Secondly, If this is not enough to convince an Atheift, yet he certainly knows, that if the Vapours drawn from Water were to fall down in the fame place from whence the Sun had raised them up, moft of 'em being exhaled from the Sea, would Jikewife fall down into it again; and that the dry Land, Fruit-Trees and Plants, would never be able to fhare in their Moisture. Moreover the Course of Rivers running from Inland Countries and Regions remote from the Sea, into which at laft they difcharge themfelves, would likewife in time be partly or wholly dryed up: Infomuch that Dews, Rains and Inundations of Rivers, that render the Earth fruitful, failing altogether, would make it at laft unfit to feed and keep alive, by its Productions, Men and other Creatures that dwell upon it.

Now this entire Deftru&tion of almoft all that breaths upon the Earth, is folely prevented by the Winds By Means of which thofe Watry Vapours, that do moftly arife from the Sea, are carried to dry Places, that they may there defcend in Rains, Dews, Shows, and other Meteors, and

fupply