Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/330

 P Y R

P Y R

is no ebullition raifed, but the liquor becomes turbid and milky. If fpirit of vitriol be afterwards added to this, to faturate the additional alkali, the liquor becomes limpid again.

7. Cow's milk mixed in equal quantity with Pyrmont water does not coagulate, but, on the contrary, becomes thinner than before, and is preferved from turning fower fo foon as it otberwife would in hot weather. This is a proof that there is no predominating acid in thefe waters.

8. If fyrup of violets be added to Pyrmont water, it turns it to a beautiful green. This is a proof of the alkaline nature of thefe waters j and it is farther proved by adding fpirit of vitriol, or any other acid, to this green liquor, which on that becomes limpid again.

9. Four pints of this water evaporated over a gentle fire, yield no more than two fcruples of a dry refiduum. Oil of vitriol being poured on this, acid effervefcence arifes, and with it an acrid and pungent vapour, like that produced by mixing oil of vitriol and common fait. If fpirit of vitriol be ufed inftead of the oil, the effervefcence is in a lefs degree, and the fait is in part changed to a bitter faline mafs, the remain- der feparated from which proves to be a calcarious earth no longer fermenting with the fpirit of vitriol.

10. If a quantity of Pyrmont water be expofed twenty four hours to the open air in a bafon, it will at the end be found to have loft all its virtues, tafting wholly infipid, and being turbid inftead of the fine clearnefs it had before, and a yellow ochre- ous earth is precipitated to the bottom; after this the liquor ■will no longer fhew any of thofc qualities which were before its diftinguifhing characters, it will no longer ferment with acids, nor turn black with galls, nor green with fyrup of violets.

It appears from the whole, that the Pyrmont waters poffefs a pure, extremely penetrating, and elaftic mineral fpirit, and that in a very large proportion; and to this their virtues are principally to be attributed. This mineral fpirit, while it re- mains engaged in a calcarious earth, imitates the properties of an alkaline fubftance ; and when joined with a fubtile mar- tial earth, it emulates the properties of vitriol, giving tht ilools a black colour, and turning a tincture of galls into ink : and while this remains in the water in thefe forms of an al- kaline or vitriolic principle of fo great fubtilty, it cannot but give them very great virtues in ftrengthening the tone of the vifcera, opening obftructions, and ftimulating in a proper manner the excretory duets, fo as to make them duly perform their office} but as foon as by the ftanding of the water open, or by any other accident, this fubtle element is evaporated, all the virtues of the water mud be gone with it. The great quantity of this powerful fpirit contained in the waters makes them more fit for the robuft and ftrong confti- tutions, when depraved by illnefs, than for the weak and tender ones ; but even the tenderer! people may take them, only obferving to take but a fmall dofe, or to dilute them with an equal quantity of common water immediately before the taking them.

Hoffman alfo recommends the Pyrmont water mixed with equal quantities of milk, on his own experience, in fcorbutic and gouty cafes. Hoffm. Opera, T. 5. p. 143, feq. Near the famous well at Pyrmont, is a ftone-quarry under ground, from fotne parts of which a fulphureousfteam comes out, which commonly rifes to a fmall height. Animals held mtbisfteam are foon fuffocated, but recover if quickly taken out. When a man Hands in this fteam, but with his head over it, it proves an excellent fudorific. Dr. Seip propofes to perform cures in feveral difeafes with it. See Phil. Tranf. N°. 44.8. feci. 4. and Mifc. Berolin. Tom. V. part. 2. fc&. 4.

Imitation of Pyrmont water. This medicinal water may be imitated very nicely by art in the following manner : take a quart of the pureft and lighteft water, add to it thirty drops of a ftrong folution of iron made in fpirit of fait, a drachm of oil of tartar per deliquium, and thirty drops of fpirit of vitriol, or a little more or lefs, as is found neceffary, not to let the alkali of the oil of tartar prevail too ftrongly, tho' it muff prevail a little. Shake all brifkly together, and on taft- ing it will be found extremely to refemble the true Pyrmont •water.

The bafis on which this is founded is the analyfis and trial of the true Pyrmont water, by which it is found to contain a fubtle aqueous fluid, a volatile iron, and a predominant alkali, all joined together into one brink pungent fpirituous water. The artificial Pyrmont thus made, if the proportions are care- fully minded, will extremely refemble the natural, and will have the fame effects as a medicine. Shaw's Lectures, p. 90.

PYROBOLUS, in natural hiftory, a name given by many au- thors to the ftone more generally called pyrites ; others have called it fiderites, pyrobalanus, pyropus, and othonna, and the Greeks myitis. Among the tranflators and interpreters of the works of authors who have treated on thefe fubjects, there has been great confufion concerning this ftone, few of them underftanding any thing of the fubject, and rendering its de- fcriptions fo injudicioufly, that they may rather be thought to belong to other ftones. See Pyrites.

PYROCTOGONIUM, in natural hiftory, the name given by Dr. Hill to a genus of foffils ufually comprehended by authors,

with many other bodies of a different figure and ftructure, under the general name pyrites.

The characters of the pyrofiogonium are thefe : it is a com- pound, inflammable, metallic body, of a regular octohaedral figure, or compofed of eight planes.

There is only one known fpecies of this genus, which i§ a, very fingular and elegant foffil, being compofed of eight tri- angular planes ; thefe being the fides of two quadrilateral py- ramids, with broad bafes, which being joined bafe to bafe, conftitute the fyrpBogonium. See Tab. of Foil. Clafs 5. This figure is very regular and determinate in the perfect fpeci- mens of this body, but there is fcarce any fbflil which is more fubject to imperfections and accidental variations. Its moft per- fect ftate is, when the two pyramids of which it is compofed are placed evenly one over againft the other j but this is but rarely the cafe, they are often placed unevenly, or flaming ; their planes are frequently of very irregular lengths and breadths, and not unfrequcntly the fpecimens are found muti- lated and imperfect, and very often a number of them co- hering in a clufter one with another, and very much mutilat- ing or injuring one another's figure. They are found of all the fizes between that of a pin's head, and an inch in dia- meter ; but the large ones are fcarce, and the moft ufual ftan- dard is a third of an inch. They are naturally of a fmootU and polifhed furface, and of the colour of wrought iron ; when broken they are bright and fparkling, and of a paler colour than without. When nicely examined as to their internal ftructure, they are found to be compofed like the marcafir.es> of a number of irregularly arranged foliaceous flakes or plates. It is found very frequently in Cornwall, Devonfhire, and moft: other of our counties where there are mines. It is fometimes met with loofe in the earth, fometimes lodged in the bodies of marcafites, or in the folid foffils, and varies fometimes from its iron colour to a dufky yellow. It is fome- times alfo found with many fpecimens connected into a mafs ; thefe are feldom uniform in fize, and cohere ia various di- rections, often greatly injuring one another's figure. Some- times alfo, as in the cafe of the cryftals, they form a large mafs, of which the outer furface onl, - is concreted, into or co- vered with regular figures, the whole inner part being a confufed fubftance.

Manes of this kind are not unfrequently found of a regularly orbicular figure, and befet all over with regularly figured py~ rottcgania of various fizes. Hill's Hirt. of > oil", p. 620.

PYROLA, tvinter-green, in botany, the name of a genus of plants, the characters of which are thefe : the flower is of the rofaceous kind, confifting of feveral petals arranged in a cir- cular form. The piftil arifes from the flower-cup, and ends in a fort of probofcis: this afterwards becomes an umbilicated and ftriated, roundifh, quinque capfular fruit, ufually contain- ing a number of very fmall feeds.

The fpecies of pyrola, enumerated by Mr. Tourneforr, are thefe: 1. The larger round-leaved pyrola. 1. The fmaller round-leaved pyrola. 3. The pyrola with fharp-pointed and ferrated leaves. And 4. The fhrubby pyr-Ja, with flowers re- fembling thofe of the arbutus. Toum. In ft. p. 256.

PYROLAMPiS, the glow-worm, a fmall infeS remarkable for its mining in the night;

The male and female differ greatly in this fpecies of infect. The male has wings, and is a fmall fly; the female has no wings, but is a large crawling worm.

The body of the male is oblong, and fomewhat flatted; the wings are fhorter than the body ; the head is broad, dun, and flat; the eyes are large and black. This has no light iflliing from it, and is not commonly fuppofed to be at all of kin to the glow-worm. See Tab. of microfcopical Objects, Clafs 1. voc. Cic'mdela volens.

The female is what we exprefly call by this name. This is a very flow-paced animal, without wings, and fomewhat re- fembling a caterpillar ; the head is fmall, flat, hard, and black, and fharp towards the mouth ; it has fhort antenna?, and fix moderately long legs; the body is flat, and is compofed of twelve rings, whereas the body of the male confifts only of five ; it is of a dufky colour, with a ftreak of white down the back. It is often feen in the day-time, but is not known till in the dark; at which time it is eafily diftinguifhed by the glowing light, or lambent flame, that is Ccen near the tail, iffuing from the under part of the body.

PYROMACHUS, a name given by fome to antimony when re- duced to a ftony hardnefs; and by others to copper, when fufed with fulphur, and thus rendered lefs ductile.

PYRONOMIA, a term ufed by the chemical writers to ex- prefs the art of regulating fire, fo as to make it fubfervient to all their procefFes in a determinate degree.

PYROPHAGI, fire-eaters, a name given by fome to thofe juglers and mountebanks who deceive people into a belief that they fwallow fire.

PYROPHORUS, the name ufually given to that fubftance called by fome the black pkojphorus. See Phosphorus. It is made in this manner : take four or five parts of alum, and one part of wheat-flour, calcine this together to a brown or blackifh mafs; powder this and put it into a vial, ftop it loofly with a paper, and fet it in a fand heat, fo as to make it continue glowing hot for fome time; after this, remove the 6 whole