Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/571

 CRY

gregates of bodies now formed in feparate concretions, at- tract the particles yet fufpended in the fluid, more than they do one another : hence they naturally become applied to thefe, and being every way equally extended over them by the am- bient fluid, they no way alter their firft figure, while they ever fo much increafe their bulk. And it "is evident, from examining the columns of cryjiah, which are ridged and ftri- ated acrofs, while their pyramids are all fmooth, that this new matter has ever been added to the pyramidal planes, and thence extended down the fides of the columns. Hilts Hift. of Foff. p. 159.

Henkel, a very accurate chernift, gives us a remarkable account of the formation of cryjial out of human urine, which feems fo ftrange, that it would have been defpifed had it come from an author of lefs credit; and as it is, will require repeated experiments to convince the world there was no error in the cafe. He tells us, that he once filled a large round glafs veffel half way up, with the recent urine of a young lad, and tying a bladder over the mouth of the veffel, he fet it in a ftove for four years together, never ftirring it during that whole time. At the end of this time he found a number of fmall white ftones, growing to the infide of the glafs ; they were of the fize of an oat feed, of a prifmatic figure, and tolerably peilucid ; they Muck fo faft to the fides of the glafs, as not to be warned of by the fhaking about of the urine, and when taken out, had no fait tafte, and were notfolublc even' in hot water. Aft. Erudit. anno i7zo,p.272. The Iargefr. and fmefl cryjiah we have any account of, were found in the mountains of Grimfule, between immenfe ftrata , of ftone; they were all, as pure and limpid as the cleared water, and the largeft of them meafured near three foot in length, and little lefs in circumference; its weight was two hundred and fifty pounds; others of a hundred and thirty, a hundred, and fo on, down to thofe of ten pound weight, were found in the fame place : but thefe Iaft were the frnall- cft there. They were all exaftly of the fame figure, being hexangular columns, terminated at one end by anTiexano-ular pyramid, and at the other end fixed to the rock, They were in general perfectly clear throughout; but in fome the bafe was foul, and in others, the point, which is lefs common in cryjidl\ but the middle column in them all was pure and fine. It is ufual with the largeft cryjiah of the German mountains, to have flaws and blemifhes ; and they are com- monly fo irregularly conftru&ed within, that they give all the prifm colours in reflection ; but thefe wholly wanted that qua- lity, and were like fo many columns of the pureft glafs, only much clearer than any glafs can be made. Phil.Tranf. N° 398. When any piece of workmanfhip in cryjial is become foul and dark, the method of recovering its luftre without hurt- ing its polifh, is this : mix together fix parts common water, and one part brandy, boil thefe over a briflc fire, and let the cryjial be kept in it, in a boiling ftate, a quarter of an hour; then take it out, and rub it carefully over, with a brufh dipped in the fame liquor; after this, it is not to be left to dry of it- felf, but to be wiped with a clean napkin, and its furface will by this means he perfectly cleaned, and rendered as bright as at firft, without that injury to the points of the cutting/or to the furfaces of the planes orfacets, which would naturally have been the confequence of doing it by mere rubbing or wiping. Natural cryjlal may be reduced by calcination, into the ftate of the bodies proper for making glafs with alkaline falts, and makes a moft fine and valuable fritt. The method of doing it is this : calcine natural cryjlal in a crucible ; when it is red hot, throw it into cold water to quench it; repeat this eight times, covering the crucible, that no duft or afhes may get in and mix with xhecrjlal\ dry this calcined mafs, and reduce it to an impalpable powder; mix this powder with the pure falts of polverine, and with thefe make fritt, in the ufual proportions, and with the common quantity of mansa- nefe j wafti this often in cold water, and after a proper time, work it; it will yield a moft beautiful glafs. Neri's Art ofGlafs, p. 102. SccFritt.

Natural cryjlal may be coloured of feveral colours, without melting or running it into glafs, in the following manner: Take a number of pieces of fine, clear and pure cryjlal, of various fizes, of crude antimony and yellow orpiment in powder, of each two ounces; fal armoniac one ounce; pow- der this alfo, and mix them well together ; put this powder into a ftrong crucible, and lay upon it the pieces of cryilal in their natural ftate, then cover this crucible with another, mouth to mouth; lute them well, and when the lute is dry, fet them in coals, which kindle by little and little; and when they begin to fire, let them kindle of thcmfelves, and they will then fmoak very much. Let this be done in a large chimney, taking care to avoid the fumes. When it fumes no more, let the fire go out of itfelf, and let all ftand till cool ; then un- lutc the crucibles, and take out the cryjiah ; thofe at top will be coloured to a fine yellow, with a deep and pale red, the colours of the common fine and balafs ruby, with beautiful fpots ; and thofe which be at the bottom upon the powder, will be of a watery colour, motled like that of the viper. This cryftal comes out fo fair from this procefs, that It may be cut as a gem, and though many are fpoiled, yet in mak- ing a large quantity, there are always fome fair and

CRY

perfta. AWs Art of Glafs, p. ,,-f. Sec the article Opal. Improper Crystals, a term introduced into the world by JJr Coppeler, in his proclnmm chryftallogvaphia,, to diftin- gu. h bodies which have the figure of cryjiah, but are not iuch from the proper or true genuine cryjlals improper cryjlals are, according to this author, fuch bodies, either ftones, metals, or falts, as have any refcmblance with true cryjlal, either as to their multangular, regular, or irre- gular figure; or as to their pcllucidity, or any other of their eflential properties. As the number of thefe bodies is very extenfive,_it was a work of great accuracy to arrange them into any fort of order; but this is one of the principal attempts of the author Among the firft clafs of improper cryflak, that is fuch as arc ftones, come all thofe gems which have any deter- minate figure, as the diamond, emerald, amethyft, and the like. 1 o the fecond belong all forts of regularly figured, metalline bodies, fuch as pyrita: and macrafites, as alfo thofe ores of Elver, where the native metal has afiumed fome regular form; as when this or any other metal moots in its natural bed, in- to the form of a tree or the like.

Under the third clafs of improper cry/lals, including the falts, come i„ all the chemical preparations of falts and faline bodies. The figure in this clafs is more determinate and accurate than in either of the former claffes of bodies. See Tab. of Micro- fcopical Objeas, Clafs 3.

We are happy enough to have at prefent, much better arrange- ments of fofiils than this. CoppeUt's Prodrom. Cryttall. See Fossils. Prepared Crystal, a term among the makers of counter- feit gems, for a powder of natural cry/lal, made for their pur- pofe. The manner of preparing it is as follows: Take the pureft and cleared natural cry/lal, put it into a crucible cover- ed at the top,fet it among burning coals; let the cryjlal be made red hot, then plunge it into a large veffel of cold water. When the cryjlal is cold, put it into the fire again, heat it red hot, and quench it again; and repeat this operation twelve times, carefully keeping afnes or any other foulnefs out of the crucible. When the calcination is finifhed, the cry/lal will be brittle and crumbly, powder it, and levigate it on a porphyry to an impalpable powder. This powder muft be made perfeaiy fine, otherwife the gems made with it will be all foul and coarfe, and no brafs or copper vcffels muft be ufed about the operation. If the cry/lal fhould be powdered in a brafs or bell- metal mortar, there could be no gem but an emerald ever be made of it, from the quantity of copper it would take up in the powdering When carefully pre- pared, it receives all the colours of" the gems, by proper ad- ditions, and affords a mafs fofter indeed, but not lefs bright and pellucid, or not lefs beautifully tinged than the fineft of the oriental gems. Neri's Art of Glafs, p. 125. Crystal, in medicine, has many virtues attributed to it, be- ing efreemed an aftringent and lithontriptic ; hence it has been given in diarrhoeas, the fluor albus, and in cafes of tra- vel in the kidneys. Its dofe is a fcruple, or half a dram "be- ing firft reduced to a fine powder, by repeated calcinations and extinaions in cold water.

Many are afraid of the ufe of thefe ftony medicines, in ne- phritic cafes. The objeaion againft f'par will hold good againft cryjlal; but there wants fufficient proofs to determine this point. In general, however, fpar is an alkali, which cryjlal is not. See Spar.

Cryftal has been recommended by fome, as a dentifrice, and there is no doubt of its cleaning the teeth ; but, like other hard bodies, it is apt to wear away their enamel, and there- by fubject them to decay. IJland Crystal. See Island Cryjlal. Crystal clews. See the article Dews. Formation »/Crystals. See Formation. Dijdiaclajlie Crystal. See LJisdiclastic cryjlal Rock Crystal. See Rock cry/lal.

CRYSTALLINE (Cyel.) - Mr. Petit, the phvf.cian, has ma- ny mmute obfervations and experiments on the colour, con- fidence, meafure, weight, &c. of the cryjlalline humor of the eye, and its capfula in different animals : but his obfervations are fo numerous that we can only take notice of fome of them. He (hews the cryjlalline to confift of concentrical lamina; : he always found the capfula tranfparent, and denies any connec- tion between this membrane and the cryjlalline, or that there are any veflels going from the one to the other; but affirms that the cryjlalline is nourifhed by abforbing the lymph lodged between it, and its capfula.

When the cryjlalline, or vitreous humors are fallen out of the eye, it is eafy to conceive, that not only the fight, but the fi- gure of the eye, muft be entirely deftroyed ; therefore, an ac- cident of this kind muft at firft be drciTed with compreffes dipped in warm wine, or fpirit of wine, and afterwards with fome vulnerary balfam. But it fometimes happens, when only the tunica albuginea, and fclerotica, are (lightly wounded, the cornea and uvea remaining unhurt, that the eye recovers it- felf: and though both the vitreous and cryjlalline humors fall out by the wound, yet they are renewed again by the benefit of nature, and the office of fight performed as well as before the injury happened. Heifrer, Surg, p 80 CRSYTALLIZATION (Cycl.) - A great number of pigments

' nr