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tailed it princes metal, from Prince Rupert, whom fome fup-* pofed to have been the inventor of it ; but the greateft per- fection this metal was ever brought to, was by two French- men, Mr. La Croix and Mr. Le Blanc. Their methods of making the compofttion, tho' both beautiful, were very dif- ferent. Mr. Le Blanc's was the brighter!, and' of the moil elegant and lively colour ; buE Mr. La Croix's was greatly fu- perior to that in ductility and foftnefs, fo that it was very eafily malleable.

Mr. La Croix invented a fort of varnifti or lacquer for his me- tal, which added a fomewhat deeper tinge to it, as it was na- turally rather too pale ; and had this farther advantage, that while it remained on the metal, it preferved it from ruft or de- cay. This is a very material point in regard to a metal of which copper is the bafis, fince that is, of all other metals, moft fubjecf. to be injured by the air, or by the contact of li- quids of almoft any kind. Mr. Le Blanc's metal is of a deep- er, yet equally lively colour, and remarkably bright; and is of fuch a temper as to be admirably fitted for working. The whole hiftory of thefe metals is certainly, that they are com- pofed of zink and copper in different proportions the one to the other; but it is not eafy, without the help of numerous experiments, to determine what is to be the true proportion for either.

The microfcope, however, fhews a manifeft difference, which may lead fomewhat towards it; for the metal of La Croix is feen to be compofed merely of a number of irregular ftriae, while the other is difcovered-to confift of always two regular beds of them, which meet in the center of the piece; hence it is that this is always brittle, and will not well polifh. The fabrick of thefe metals was long kept a fecret ; but it was al- ways to be difcovered by melting it in a crucible in a ftrong fire, when it always fent up plain flowers of zink, and the remaining metal appeared no other than copper altered by ca- lamine; that is, common brafs. Mem. Acad. Par. 1732.

PRINCIPALIS, in fome antient Latin writers of mufic, is u fed for the chord or note called vn-j.tr, by the Greeks. See the articles Hypate, Tetrachord, and Diagram.

PRINCIPIUM reeli abdominis, in anatomy, a name given by Vtfalius to a mufcle generally known at this time under the name of the pyramidalis.

PRINCIPLE (Cycl.)— Some antient philofophers diftinguifhed between principles, «gjc«i, an 4 elements ro^- c '«. Principles ac- cording to them, were neither compofed nor produced ; but the elements were complex or compounded beings. Pluttirch, ap. Eller. in Mem. de l'Acad. de Berlin, 1746. It would be endlcfs to enumerate all the opinions of philofo- phers concerning the elements of bodies. A late author has given us a furnmary of many of thefe opinions; and, laftly, adds his own, that fire and water are the only things which properly deferve the name of elements, or principles of na- tural bodies ; fire being the active, and water the paflive prin- ciple. According to him, water is convertible into air, and into earth, by means of fire. Hence the four, vulgarly called elements, may be reduced to two. He endeavours to eita- blifii his doctrine on the experiments of Boyle, Hales, and Mufchenbroek. Vid. Eller, in Mem. de l'Acad. de Berlin,

1.746.

Original Principle, pnncipium originate, a name given by Ta- chenius and fome other authors, to fait, without considering it as acid, alkali, or of any other particular kind, or any mode of exiftence. The fait of wood or vegetables, not being alkali till after burning, and fo on ; but fait that is the bafe of thefe, being evidently exiftent in the bodies, and, in regard to wood, feeming indeed to conftitute its character as fuch, fince the evaporation of it caufes the wood to loofe all its ftrengtb and to decay : for we find that in rotten wood there is no alkali at all; and the Venetians, who fink their timber for fhip-building into water while it is green, prevent, by that means, the evaporation of thofe falts, and leave the wood little lefs durable than {tone. On thefe and the like principles, Tachenius fuppofes fait to be the true original principle of bodies ; but many others allow this name only to water, or at leaft that water is, in almoft all natural bodies, the moft copious, the moft active, and the moft influencing part .; yet even this is found to agree much better with fome bodies than with others. The birch and elder feed more kindly on a thin uliginous moifture ; the elm, the pine, the fir, and cedar, chufe a ftrongcr liquor; yet thefe and many more, the moft widely different that can be from one another are often feen to draw their whole fuftenance and bulk, whe- ther annual or perennial, from the fame piece of ground, im- pregnated fo far as is poflible to be judged of with the fame fort of juices, and from the ambient air and dews, when as vet by our beft diligence we cannot diflinguifh the liquors or ialts* approaching clofely to their feveral roots; and if we wholly take away, and exchange all the earth from the roots of trees whofe barks, fap, and fruit, have very much differ ing falts, and are of very different kinds, yet we fliall find each tree to profper better by the exchange, inftead of being injured by it.

Hence we may fufpcdt, that the very contextures of the bodies of plants, from the firft germination of the feed, and as they form gradually from the invisible principles of their feeds

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are, however fmall and imperceptible, the natural alem- bics, where the common water and air are changed into the different juices, gums, refins, fcrV. as the animal organiza- tion in the body of the cow changes the juices of every fort of grafs and efculent vegetable, into one and the fame milk I he fea-plants growing on (hells, or affixed to yet harder lrones, taking no nourilhment from the thing they grow on, but being as it were all root, and taking the whole from the ambient water; yet that water giving to different Ipecies of them, tho' itfelf the fame to all, the different tex- tures of herbaceous to fome ; tough and horny to others ; and to fome, abfolutely ftony; as to the corals, many of which have been efteemed by the generality of authors, abfolute (tones.

Trees of feveral different kinds are found in America grow- ing out of the fame dry and hard rock, and the various kinds of fucculent plants; the,poifonous ones and their oppofites, or remedies as the euphorbium and the antieuphorbium ; the mo it acrid and pungent, and the molt foft and emollient, out of the fame barren lands of Arabia, where it could not be expefled that any plant could grow at all. Hence it is eafy to apprehend, how the feeds in their time, and after them the roots, items, and leaves of trees, may be the proper (trainers to feparate and prepare the feveral faps and juices, and to fer- ment the liquors into their feveral particular falts. See the ar- tide Vegetation and Salt. Principle, in chemiiiry. It is impoflible to difcover the vir- tues of any body, or to find how mixed bodies of different kinds ftand related to the human body, either for the prefer- vation of its funaions entire, or the reftoring them when loft or impaired; or, finally, for the total deftrufliori there- of till we know the principles of which they confift, and likewife the mixture and proportion of fuch principles in bo- dies to which their effects are chiefly owing. Wherefore Having difcovered by various ways the parts into which a true chemical analyfis refolves bodies, we muft look upon fuch limple parts into which all mixts are rcfolvable, and of which they feem to be compounded, as their true and genuine Prin- ciples, r

The antient chemifts' having obfer.ed, that in analyiing all bodies whatever, they obtained a fpirir, or mercury, fulphur hilt, water and earth, concluded the number of principles tj be five. If wine, for inftance, be diftilled in a proper alem- bic, a burning water or fpirit will firft arife, and next an in. hpid water, which they call phlegm ; a thick vifcid mafs alone remaining m the (till; this put into another veffel, or retort and expoled to a more intenfe and violent heat, a fmall por- tion of phlegm comes over firft. then an acid water, which according to them is ftill fpirit or mercury, and next a tit oily (ubftance, called fulphur : what remains ftill in the re tort is next burnt to aihes in an open fire; thefe alhes are tlirown into an earthen veffel, with a proper quantitv of boil mg water, which they impregnate with their fait; this water bang hltred thro cap paper, and afterwards evaporated leaves, the (alt at the bottom of the veffel ; and tha other part of the alhes, which the water could not take up, or have any eft'ea on,, s termed the earth of the fubftance, or its caput mor- tuum.

Of thefe five principles the chemifts have reckoned two to be paffive, water and earth ; and three to be aflive fpirit fill phur, and fait ; and on thefe laft they have thought the whole virtue of the mixed body depended In this analyfis we may obferve, that .there is a twofold fpirit ; one oily 'and inflam- mable, winch r.fes firft by a gentle heat, and is termed fpirit of wine another acid penetrating like that of vinegar Be- hde thefe, the chemifts give the name of fpirit to other pene trating volatile, or urinous liquors, obtained from the parts of animals ; fuch as the fpirit of urine, hartfhorn, and fuch like fubftances : but the later chemifts have banilhed thefe fpirits from the numberof their principles, as being-nothing elfe than fulphur and (alt diffolved in water. Thus fpirit of nitre and others of that kind, are only acid falts in water • fpirit of hartfhorn, or urine, alkaline falts; and fpirit of wine or of turpentine, an Ethereal attenuated oil.

Some of the moderns deny likewife, that either fulphur or lalt deferve the names of principles or elements, as not beino- the moft fimple fubftances producible by chemiftry For fuf phur, when heated with due care, may be refolved into fait water, and earth ; as is evident by diflilling fetid diftilled oils feveral times with quick-lime, which by this treatment yield in large quantities a volatile fait, diffolved in phlegm tOEe ther with a caput mortuum or earth. .Ethereal oils a'lfo are only fat thick oils, like that of olives, attenuated by falts' and diffolved in water; as may be proved by thefe two experi- ments. Jf oil of ohves, or any other of that kind be mixed with a fermenting liquor, fuch as a folution of honey in wa- ter; the whole may be converted into an inflammable fpirit. And if a quart of fpirit of wine, diluted with fix quarts of common water, be expofed in a cold place to the open air, the volatile falts will fly off and leave drops of oil fwirnmirV at top, which are in every refpefl the fame with oil of olives or almonds.

Salt is no more a principle than fulphur ; becaufe it may, by proper management, be at length reduced to earth and water.

Thus