Page:Cyclopaedia, Chambers - Volume 1.djvu/783

 FIR

(1:)

FIR

Flame Teems to be nothing but a thick Sulphur agitated, as before, by Elemental Fire$ fo as the Fire is driven with a great Motion around the revolving Particles of the Sul- phur. See Flame.

Soot) feems to be produced, when Fife and Sulphur can- n ot bre<tk into a Flame; being a fort of Coal, confiding of a thick Sulphur, and an attenuated Oil with Earth and Salt. See Soot\

Smodk feems to be the combuftible Matter, when it be- oins to be relinquifli'd by_ the Elemental Fire: For, if this Smoak be afterwards pafs'd thro' a Flame, it will it felf become Flame, as before. See Smoak.

Laftly, Afbei are the Earth, and Salt; which the Fire leaves untouch'd. See Ashes.

Fire may be diftinguifh'd into Shining., and not Shining: For, that there is Fire which does not emit Light, is evi- dent hence, that a piece of Iron taken out of the Fire f before it be red hot, {hall yet give Fire to Sulphur.

Shining Fire again may be fubdivided into two Kinds: That which ivarms, as red hot Iron; and that which does not warm, as that obferved in putrid Fifties, rotten Wood, tfc. The Oil whereof beginning to be agitated, and atte- nuated, produces Light, without any Heat, fo far as the Thermometer may be a Judge.

Qf Shining^ and at the fame time Warming Fires, the principal is that of the Sun, as it is called; tho', whether the Firebe really emitted from the Body of the Sun ; or whether it be only the common, vague, univcrfal Fire, determin'd by the Sun, is not eafy to fay. This Fire we moreufual- ]y consider under the Denomination of Light. See Sun, and Light.

This Solar Fire, in calcining certain Bodies, makes fome Addition to the Weight thereof.

Thus, Antimony expofed in the Focus of a Burning Glafs, will fmoak a confidcrable Time ; and the greatelt Part of it feem to evaporate in Fumes: But, if tried by the Balance, it will be found to have gain'd in Weight. And if it be again applied in the Focus of a larger Glafs, it will again emit Fumes ; and yet ftill be increafed in Weight.

Befide the Solar, there islikewife a Subterraneous Fire.

This appears in digging under Ground : For the firft Glebe, next to the Surface, is warm'd by the Heat of the Sun; and as you go deeper, you will find it colder ; whence in hot Countries they have Confervatorics of Ice at fome Depth under Ground : Till, arriving at a certain Depth, viz. forty or fifty Foot, it begins to grow warmer ; fo as no Ice can there fubfift : And at a yet greater Depth, 'tis fo hot, as to take away Refpiration, extinguifh Candles, £5^. And if the Miner will venture further, and carry a Candle along with him, he frequently lets the whole Place in a Flame, the fulphurous Fumes render'd volatile by the fubterraneous Fire, catching Flame from the Candle.

Whence it appears, that there is another Source of Fire, or another Sun, in the Bofom of the Earth, which gives Mo- tion and Life to every thing growing in, or upon the Globe ; and even, that the Centre of the Earth is mere Fire : which Fire is likewife argued to be perpetual from Vulcano's or burning Mountains, which have been known to caft up Fire, from the earlieft Account of Times. See Vtjlcano.

There are two great Fires therefore, the Higher, or So- lar ■ and the lower, or fubterraneous ; in every other refpect perfectly alike. See Subterranean, Central, So- lar, &c.

Fire, in Chymiftry, is the great Inftrument, by which mod of the Operations of that Art are perform'd. See Chy-

M1STR V.

The Kind, Degree, Direaion, Sfc. of Fire are Things the Chymift is principally to attend to. The Diverfity of Fire makes a great Difference in the Refult of the Experi- ment; fo as, the fame Effect, e.gr. Ihall not a rife, if an Experiment be made with the Fire of Spirit of Wine, and that of Pitcoal.

And to this Caufe, Mr. "Boyle, in his Treatife of the un- expected Failure of Experiments, attributes it, that a great many Experiments fuccefsfully tried by fome, have not fuc- ceeded to others.

The Fires chiefly required by the Chymifrs, arc fuch as yield no Farces, or Remains ; no Salt, or Smoak : And fuch alone are thofe of the Sun, and of Spirit of Wine. Thofe which come next in Purity, are Oils diftilled per Veficam ; which lofe their Earth and Salt, by their Boyling and Agi- tation in the Water; fo that the oftcner the Diftillation is repeated, the purer they are render'd : After thefc come Turf.

Indeed, the very Manner wherein the Fire is blown, is found to have fome Effect: Thus, Accfia,lib. 4. c. 5. relates, that in '-Pc/7,?, when they would melt and feparatc their Sil- ver from the Earth, &e. if the Fire be blown up with Bel- lows, the Fufion will not fucceed: Nor will any other Fire do but that blown by the Wind raifed from the Fall of fome Water; fo that they are fore'd to have Recourfe to large Tubes bid to the feet of large Mountains, or Cataracts to

convey the Wind generated by the Fall of Water to fhC;r Works.

The Degree of Fire ; or the Collection and Direction of Fire, to the Degree proper for each Operation, is almoft the Whole of Chymiftry : For the Ftre, e.gr. requifite to melt Metals, is by no means proper for the Ditlilling of Spirit of Wine,

Now, the greater or lefs Force of Fire depends altoge- ther on a greater or }efs Quantity thereof collected into a Focus : For, as to its Motion, it does not feem in Our Power to alter it; or to make any Increafe or Diminution of the Force of the Fire on that account.

The Chymifts ufe four principal degrees of Fire in their Operations*

The Firft is equal to the natural Heat of the human Bo- dy; or rather that of a Hen, hatching her Eggs ; which is the Standard : And accordingly this firft Degree is beft mea- sured by applying aThermometer to a Hen ; and lome Chy- mitts, by keeping a Fire continually to this Degree, by means of a Thermometer, have hatch'd Chickens.

By this Degree all their Digeftions, e.ify Separations and Solutions, gentle Diflillations, with all Fermentations and Putrifacrions are perform'd. See Digestion, Distilla- tion, &c.

The Second Degree of Fire is that which gives _ a Man Pain, but does not deftroy, or eonfume the Parts : Like the Heat of a fcorching Summers Sun, which chafes and in- flames the Skin ; and even fometimes railes BlifterS.-

It is ufed in making Separations of the more ponderous Bodies, which the firft Degree is not equal to; as alfo in fome Fixations, particularly that of Mercury, which is ren- der'd fix'd by a gradual Introduction of fuch Fire among the Parts of the Mercury.

It makes the Serum of the Blood, and White o£ an Egg coalefce, and fo occafions deadly Inflammations ; and is too intenfe for any Digeftion, Putrifaftion, or Fermentation to be effected by it.

The Third Degree of Fire is that of boiling Water, which feparates and deftroys the Parts of Bodies. This Degree is perfectly ftable ; for Water, when once it bnils, is at its utmoit Degree of Heat, and cannot be rais'd a whit further, by any Augmentation of Fire :, or Fuel ; as was firft obferv'd by Monf. Amontons.

This Degree ferves to attenuate, feparatc, fix, and penonn other Operations, where the two former would not be ef- fectual.

The Fourth Degree is that which melts Metals, and de- ftroys every thing elfe.

This Degree is too vehement to be eftimated by the Ther- mometer ; that Inftrument not being able to endure it ; io_ that it is only determinable by its Effect in the Fufion ot Metals : As the Heat ot boiling Water cannot be increalcd, fo neither can that of melted Metals.

This Degree is ufed in abundance of Operations, and par- ticularly about Minerals, where the three preceding Degrees are infufflcient. This is the lail Degree known to the anti- ent Chymifts.

The lateft Chymifts reckon a Fifth Degree of Fire, viz- that where by Gold is made to emit Fumes, and evaporate.

This was firft difcover'd in the Year 1690, by Mr. -Ijcbtrn- haufen, whofe Burning Glafs render'd every thing, even Gold it felf volatile. See Volatility^ Burning Glass, Gold, £5>c.

Befide thefefive Degrees, the Chymifts have feveral in- termediate ones; all which however may be eafily redue'd to the former;

As, the digefling Fire> or Venter Eqtii, which is the Heat of a Dunghil.

The Balneum Mari<£, Arenofum y &c. explain'd under the Article Balneum..

The Naked, or Immediate Fire, which is the common Fire applied under a Veffel.

The Fire of a Lamp, which is moderate and equal, and may be increafed by trje Addition of more Wick ; ufed by Enamellers, £$c.

The Wheel Fire, which is lighted all round a Crucible, or other Veffel, to heat it all alike.

That called by Suppreffion, which is when the Veffel is not only encompafs'd round, but cover'd over with Fire.

The Rcverbcratory Fire, when it is in a Furnace dole a-top, by which the Fire is reflected back, and all around upon the Veffel. See Reverberatory.

The Melting, or Fufing Fire, for the Solution and Calci- nation of Metals and Minerals. SeeFuaioN.

The Glafs Jjonfe Fire, for the Vitrifying of the Afhcs of Vegetables. See Glass.

And the Olympick Fire, which is that of the Sun collected in the Focus of a burning Mirror, £ivc.

To the feveral Degrees of Fire required, feveral Forms of Furnaces are accomodated; which lee under the Article Furnace.

There are five principal ways of altering the Degrees of Fire* * K. Foe