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Whole interval we find certain plants give indication of life and growth.
Thus in the fevereft winters cold, we find the moflcs grow- ing on the barks of trees, and what is more remarkable, they only grow and produce the rudiments of their feeds at fucii times. The fir, juniper, larix, cedar, pine, favin, yew, ar- bor vitse, and other evergreens, maintain their verdure in fe- vere frofts ; the like holds true alfo of the corellines, earth moffes, black hellebore, the winter aconite and many other plants, which will fhoot, bloiTom, generate, conceive and bring forth their feeds under the fevercft colds, which are un- able to check their conjugal heat ; in fine, were we to rife from the loweft to the higheft pitch of thefe degrees of heat, and then recount all the known plants, we fhould find fome growing and flourifhing in the extreamelf. limits of it, and in every intermediate point;
Hence it appears probable, that a chemift by duly conducting this degree of heat in an artificial ftove might imitate the various heats of nature, fo as to cherifh all plants, not to deifroy them ; and in the offices of chemiftry for the raifing this de- gree of heat a furnace might be made, and on this a vufiel full of water fet, and to this a thermometer applied, which by its rifing and falling would indicate the degree of heat required. Then placing glafs veffels in the water thus tempered, the fub- ftances are to be put into them, which are to undergo this de- gree of fire. This degree of heat feems calculated to be the mod proper for impregnating oils with any excellent precious vegetable fpirit without wafting. Thus to communicate the fragrant fcent of rofes to a given oil, the beft method {hould feem, to take pure inodorous and infipid oil of olives, and put- ting it into a tall clean chymical glafs, digefl: it in a heat of fifty-fix degrees, with the moft fragrant rofes gathered juft as they are opening in a morning; by this means the heat will unite the fpirit of the flowers with the vifcidity of the oil, in the moft intimate manner, and exhibit a highly odorous bal- fam. The application of a fimilar degree of heat would im- pregnate alcohol with the pureft fpirit of fafFron ; a lefler heat fcarce fervingto extract this fpirit from the body, while agreat- er will diflipate and evaporate it, or at leaffc the more volatile and fine parts of it.
The fecond degree of heat may be commodioutly taken from that which obtains in animals, and which may be fup- pofed to commence at the fortieth degree of the thermometer, and end about the ninety fourth ; within this compafs, ani- mals may live and fuhfift, that is, if their juices be of any de- gree of heat within thefe bounds. Some infects feem to have fo little heat in their juices, that it is wonderful to conceive how their eggs can fubfift unhurt, during hard winters ; as the eggs of caterpillars and the like; but yet they do, and hatch in the fucceeding fpring.
Fifties as well of the fea as of rivers, live in a watery medium, which is only thirty-four degrees hot, and confequently their blood and juices are of the fame temperature, yet they can bear any heat from thence to the fixtieth, and live in that and a fomewhat farther heat: but fifties that have lungs, and all breathing animals, conceive a greater degree of heat in their juices, which when healthy, are (bund to rife to ninety-two degrees hot ; therefore the limits of this degree are fixed at thirty-three and ninety -four; within which compafs all the vital functions of all animals, the fermentations of all vegeta- bles, and the putrefactions of animals and vegetables, as alfo their generations, geftations, incubations, births, nutritions, are performed, Boerb. Chym. pt. i. p. 374. This degree is ufed by the beft chymifts for making elixirs, and volatile alkaline fairs, both fimple and oily, alfo tinctures, and the digeftion of the philofophic mercury for the ftone. The third degree of heat, is that which extends from the ninety -fourth degree on the thermometer, to the two hundred ^md twelfth, at which laft, water ufually boils ; in this whole degree the water and native fpirits are feparated from all ve- getables and animals, and the remainder drying, becomes du- rable and almoft immutable. The cffential oils of plants thus become volatile; but the falts and oils obtainable from the re- cent juices of animals, fcarce rife within this degree, but ra- ther dry into a thick, hard, brittle, infipid, inodorous mat- ter, which remains unchanged for many years; by which ap- pears the falfehood of that common opinion, that volatile al- kaline and oily falts are generated and found in the hcalthv bo- dies of men in this degree of heat. All diftilled oils are prepa- red, and all the medicated waters of fimples are diftilled in this degree ; and the fanguineous and ferous humours of animals i coagulate by boiling water, into fciffile mafles ; all their folid ' parts are deftroyed and turned into a thick tenacious liquid ; and confequently all animals deftroy'd therein. The fourth degree of heat maybe taken from 212 to 600 de- grees on the thermometer, within winch compafs the diftilla- tion of all oils, faline lixiviums, quickfilver and oil of vitriol is performable; within this degree alfo, lead and tin will melt -and mix together. Oils, (aits and fapos, both of animals and vegetables, become volatile and acrimonious in this decree, tending more or lefs to an alkaline nature; their folid parts drying up, and burning into a black coal. In fine, all thefe
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matters are utterly deftroved, and have their nature chan„u and lofe their powers in this degree of heat; and foffilc fulnb, and fal armoniac are fublimed in the fame. The fifth d ■• of heat, is that wherein the other meals' melt, and w hirh commences from 600 degrees, and ends at that heat bv which iron is kept in fufion ; in this degree moft bodies are deftrov'd • glafs, gold, filver, copper and iron remain long unchanoed in it, all other fixed bodies grow red hot in this degree ; the fi ed falts of vegetables and follils melt, are deprived o'f molt of their oils, and are raifed further and further toward an alka line acrimony, and thus with fand or flint turn to glafs. J* this heat limeftones calcine, and all other bodies, either vim" fy or become volatile, and are dflipated in the air. The fixth and higheft degree of fire, is that made either bv a lens or a burning fpeculum ; this fcarce any fubifance is -ble to withftand, and gold and the diamond are considerably" al tered by it. The almoft univcrfal effefl of this degree of fire is the turning all fixed bodies into glafs, whence it is laid down as a rule, that the utmoft effedt of fire is the vitrifica- tion of fixed bodies ; and this the anticm lages of Alia feem to have been apprifed of, as they fay in all their prediction., that the whole world flail at length peril!, by fin ami be turn ed into tranfparent glafs. Having thus icgulated what are the degrees of fire, it remains to fay in what manner a fire may be raifed and maintained in any given degree. Boerb. Chun part 1. p. 376.
Alcohol or fpirit of wine affords a very feeble but equable heat- and this may be managed and direcied to feveral regular de- grees by lighting up more or fewer wicks at a time, under the veflel to be heated.
After alcohol follow other light fpungy and porous fuels, feci, as hay, ftraw, rufl.es, dried leaves, hair, feathers, fawduft, barks chaff, bran, &c. After thefe come oils, tallow, wax camphor, pitch, rel.n, fulphur, and other inflammable fub! fiances prepared from thefe j then folio-/ the thick, hard and heavy woods, not over dry, and the coals made from thefe • and laftly pit coal, and red hot metals. And tho' the mate- rials or fuel be the fame, a different degree of heat may be given by ufing a fmall or a large quantity at a time The heat produced differs alio according to the objefl to be chano'd and its dlftance from the fuel ; as all heat decreales in propor- tion to the diftance from it, and laftly the degree of fire may be modified by making, (firing, or complying the hid, or the any vault grounding it j hence bellows become of pro- digious ufe m railing the power of fire from the (ame fuel or materials ; to all this it is to be added, that the degree of fire is to be greatly regulated by the figure of the furnace, that be- ing conftrufled with an arch'd top, may be fo difpofed to re- 1UI %* ".Heft its power to fome one place; and if a I thefe affiftances be applied at once, we have the higheft puf- iible degree of vulgar fire.
The dread that wild beads have oS fire, i s very furprifing. The natives of the Cape of Good Hope, chafe away the lions from their cattle by means of fire; and the Ceylonefe drive tigers, &c from their plantations in the fame manner. By means of fire deer, elks, &c. may be caught in this manner ; two men go out into the woods in the night, one of thefe takes an earthen veflel on his head, with/,-, in it made of flicks and rel.n, and ,n one hand he carries a flaff with eight bells on It, and the other goes clofe behind with a fpear in his hand • when the deer &c. fee the light and hear the bells, they come up, ftand, and gaze, while the (bear man kills them The men are in no danger from tigers, &c. for they run away from the fire. Fhd. 7 ranf. p. 1094.
Fi re from cold Span. It j, poflible to produce fire and flame by the bare mixture of two cold liquors in the following manner ■ take two drams of ftrong and frefh fpirit of nitre prepared With 0,1 of vitriol, and putting it into a clean and dry gallipot fet It under a chimney, then pour to it at once of the oil of cloves one dram, thcie will be immediately produced a loud noife, and a confiderable flame, and when that is gone a drv reiin is formed in the pot. ShauftLeQ. n 309
UmlM Fires, Among the number of thefe lambent or inno- cent flames, is the mining of meat at certain times It has been ufually fuppofed, that this was owing only to the pntre faflion of the meat, and that it never fhone till ft.nkine: or nearly fo, but experience proves the contrary. We have in the Phdofophical Tranfaflions an account of a piece of veal which was obferved to fhine the night after it was killed and yet when eaten the day afterwards was perfectly Tweet 'and -i part of it that was kept by way of experiment continued aood many days after. This is not of the nature of common fire or flame, and not only differs in not burning, but in this il fo, that it is not extinguifhable in water. A perlbn ftriking this piece of veal, had the flame covering hi, whole hand, and that continuing, even when he had put it under water but the wiping ,t with a towel, carried it all off and deftroved it It is not uncommon to find the guts of hogs when dreiied by the good women for the making what they call chitterlings, and put into the pickle, fhine in this manner. Some of the pieces while under this management ufually fwim on the water and others fink in it. Thole which fwim, are the
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