Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/223

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fubftance they were among;, which was evidently all loft and fluid at that time. Augufiino Scilla de Petrifact. The petrified vertebra: of fifties cannot be fupp >fed real fofiile productions, but are plainly remains of animals j and when examined ever Co accurately, they are found to agree with the fame bones in the recent animal in every lineament Scilla mentions a fofule lobfter's claw preferved in his iftu- fieum, and found in the hills near Meflina, in which a piece of a fcallop-fhei! was found clenched juft in the manner in which that animal feizes its prey. Thofe who fuppofe thefe foffiles to be really produced in the earth, furely cannot fup- pofe that there could be any femiiul principle only for the claw of an animal. In Poland there is a kind ol flone called mec kairmi, which they bring from a place called by the -fame name. This flone has very much the appearance of the grain of wood, and is probably wood pe- trified. Rzaczinfki, in his hiftory of Poland, mentions the place, and tells us, that there are many whole roots and parts of the trunks of trees petrified there. He tells us alfo of an old beech tree in Podolia, whofe lower part is not only pe- trified, but that into the hardeft and pureft of the common ftones ; it being converted wholly into flint, and ferving the country people thereabout f.r their common ufes as fuch. The author tells us, indeed, that the lower parts of trees become petrified rhere as they ftand, and while the upper parts continue growing ; but this fcems fcarce credible. We have indeed fome other accounts of the fame nature, but not from authors of fufficient authority to build our faith on, in fo feemingly unnatural a cafe. This author, in par- ticular, feems too credulous in many inftances ; amon^ other things, giving us an account of fome earthen veffels found at confulerable depths in the earth, which he fuppofes to have been formed there by nature. We have other accounts be- fide this of foflile urns, but the authors of them all have either miftaken the cruflated ferrugineous bodies for urns, or elfe they have fuppoied things natural which are certain- ly artificial. RzaczinfkFs, Hi ft. Polon.

Mr. Boyle mentions a kind of fandy earth found in England, which turns wood into flone, tho' there be no petrifying fpring near the place : and this, he fays, is done in a better manner than by any water he ever faw. See Works Abr. Vol. i. p. 161. Animal Petrifactions, a term ufed to exprefs fuch petrifac- tions as are found in the feveral parts of the bodies of living creatures.

Of thefe the human body affords many which are the occa- fions of very terrible and generally incurable difeafes. The philofophical tranfa&ions afford us two very Angular inftances of this fort of petrifactions ; the one in a woman, whofe whole left kidney was intirely petrified, not being filled up in its cavity with a flony concretion, as frequently happens in ne- phritic cafes, but its "whole fubflance converted into ab- solute flone, only covered with a thin fkin. The other inftance is in the cafe of a confumptive per ft n, whofe lungs were found, on difi'ecfion, full of ulcers, and thofe having almofl all of them, more or !efs gravel in ihem ; but this was not all, for feveral large pieces of the lungs were found, as the kidney in the other inftance, wholly con- creted into flone, on!)' covered with a thin fkin: Phil. Tranf.

Petrifactions of Lough Neagh. The moft noted place for petrifeSliom in our dominions is, the famous lake called Lough Neagh, in Ireland. Aloft of the antient writers w. o have given accounts of Ireland, have mentioned the power the waters of this lake have of turning wood into {tone; and fome of them have added the abfurd to the marvellous, by affirming, that it would turn that part of the wood which was buried in the mud into iron, that part that was in the water into flone, while the part which was above water re- mained mere wood ftill.

Some late authors, as Molyneux Nevil, Smyth, Wood- ward, and others, ftippofe this effect not to be found in the water of this lake, but that it either is in the earth about the lake, or elfe that the petrifactions found there are not fuch as have been formed there, but petrified elfe where, and long fince, and brought thither by the waters of the deluge. Mr. Smyth affirms, that no experiment ever made has proved that the water of that lake has any power of petrifying wood ; and gives an example of a gentleman's having planted two flakes of holly in the lake, on purpofe to try; which were taken up after 19 years, without the leaft advance made to- ward petrifafiion It is certain, indeed, that vaft quantities of petrified wood ate found in the lake, and even whole trees with their roots and branches all turned to flone, have been found buried in the mud of it; and it fhouJd kern the moft rational account of their being found there, that they had thrown in their natural ftate on the banks of the lake, it is equally certai, that of the great quantity of wood met with here, the different pieces are in different degrees of pe- trifailhn ; and that feveral of them are (een to be petrified in different degrees in their parts; nay, that one fide of a large piece Is often fcen to be mere rotten wood, while the other is hard flone. Suppl. Vol. II.
 * md bad, in fine, fallen in, and been there petrified. And

it is not to be afferted, becaufe flakes driven down in fom one part of the lake are not petrified in a fin all number o f years, that therefore the water has no where a petrifying vir- tue ; fince it is poffible that there may be fprings arifing in fome parts of it, the waters of which may be fo highly Tm*- pregnated with ftony matter, as to petrify wood, if they meet with it near their origin ; yet the waters of thefe, when mixt with that vafl body of water which makes the whole Jake, may not be able to communicate that petrifying quality to fo large a quantity.

T here is fcarce any water that does not contain faline and ftony particles, which may be feparated from it by evapora- tion ; and the generality of petrifying fprings, when examin- ed by this procefs, are found to be very full of calcarious, or other ftony matter, and frequently of ferrugineous and vi- triolic kinds. Thofe which contain calcarious matter, when they drop upon flicks, mofles, or other vegetable bodies, ail: on them by incruftation ; their calcarious particles being left behind while the water goes off, and forming by this means iucceflive crufrs fometimes to a great number, which adhere clofely to one another, and form a ftony coat to the wood : if thefe be broken at different periods of time from their formation, fome of them will be found with the wood re- maining found within them, others with the wood rotten; and others with a flony matter of the fhape of the wood, fupplying its place, and formed by the depofition of ftony particles in the cavity left by the perifhed wood. Sometimes, indeed, thefe waters permeating the pores of wood, fill them up with the calcarious particles they leave behind them ; and when the vegetable matter is perifhed, the calcarious concretion remains in its place and exact fhape. The bodies in this laft ftate approach much more to the nature of pe- trifaSiions than the others, but they all differ greatly from the genuine petrifacli.m j becaufe it is not true flone that they confift of, but merely a fpar or calcarious matter, which readily ferments with, and is foluble in acids, and by a flight calcination is reduced to lime, in the manner of other fpars. The petrifying waters, which contain particles of true and genuine hard ftone, and perhaps with them fome ferrugine- ous or other metallic ones, do not ail in this manner by mcruftation, but always leave the furface naked, and pene- trate into the inner fubflance of the wood, filling every pore with the hard matter they depofit ; which, in fine, without altering their texture or fize, adds greatly to their gravity, and gives them the bardnefs of a flone. In many parts of Ireland there arc great quantities of the incruftations of cal- carious matter on vegetables; but the petrified wood found. in the Lough Neagh, and on its (bores, is wholly of the other kind ; and Ihcws no covering of any foreign matter, but preferves the grain and all the veftigia of wood; all the alteration is in the weight and clofenefs refulting from the ftony matter having filled all the pores : thefe make no effer- vefcence with acids, nor will be calcined into lime in a com- mon fire, as the calcarious incruftations are. It is probable, that the petrifying matter with which the wa- ter of fome part of this lake is endued, is owing to feveral fprings ; which running in their courfe thro" mountains where there is abundance of ftony and mineral matter, wafh off and carry with them great quantity of the particles of one or both thefe fubftances ; which they afterwards depofit in the wood they meet with, where they are difcharged up thro' the mud of this lake ; and that tho', when blended among the general water of the lake, they have not this pro- perty, yet if the flakes of holly had been driven down juft where thofe fprings were, they would probably have been petrified, tho' there was no fuch quality in the reft of the water of the lake And that there are thefe fprings in fe- veral parts of the lake, is certain from hence, that when in the great froft in the year 1740, the great lake in general was frozen over fo as to bear^men on horfeback, yet feveral circular fpaces remained unfrozen.

The petrified wood is found in confiderable plenty on the fhores of the Lough, but moft abundantly after ftorms ; and this rolling about of the petrifactions at the bottom in ftorms, makes it not eafy to fix upon the place where they received their alteration.

Nor are the petrifactions found only in and about the lake, but they are turned up by the plough almoft daily in all pla- ces, at two or three miles durance from it; and fome have believed that they were all /a/ides fui generis, and never had been wood till the roots of trees were found in their natural pofition in the ground, with their frnaller ramifications and every other part wholly petrified.

Many of thefe are much fofter than the petrifaftiont in the lake, and may be cut and cleaned with a knife, tho' not near fo eafily as other wo^d. It is not impofiible, but that many of thefe may have been originally petrified in the lake, which may have either once extended over a much larger fpace of ground than it now does, or elfe have loft on one fide what it has gained on the other; not that it is neceflary to fuppofe this, fince there is no doubt but that mineral fleams and exhalations being highly fated with flony particles, are often found to have a petrifying virtue; and fuch effluvia ari- fin<* thro' the earth may operate on wood accidentally buried 2 F f 'in