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generation is a true cryftallization. The queftion then is reduced to this problem :-can the liquors capable of forming an organifed being by cryftallization be prepared only by other organifed beings. This is the most common procefs of nature at this time, though, at the first beginning, fhe may have followed a different plan. It is then demonftrated that she may ftill employ it, and obfervation can only decide, whether the has entirely renounced it.'

The inconclufiveness of the above reafoning is too obvious to require refutation. It is only neceffary to remark, that fpontaneous generation, in our author's language, is very different from the fame system of the earlier English philofophers, who poffeffed equal ability, judgment, and piety. They suppofed that the Almighty had originally created matter with dif tinct properties, capable, in given fituations, of producing beings without his immediate interpofition; nor was it, in their opinion, at all derogatory from his honour to fuppofe him capable of forming a vaft fyftem, where each diftinct part had a power of repairing its own defects, or its gradual decay. It is obvious, that the fyftem of M. de la Metherie is very differ

ent,

If we were to examine fome other part of this author's theory, we fhould find it equally defective: in that paffage, particularly of his theory of the earth, for instance, where he contends, that metallic veins are coeval with the rocks in which they are contained, because if a cavity had been originally left, the weight above would have crushed the superincumbent part. A little reflection would have fhown him, that it is not neceffary a hollow fhould have been originally in that spot, and that the refiftance from the cohesion or the arched form might have been fufficient to have preserved it. We know that there are vaft cavities in the earth, whofe roofs are fupported by thefe means.

A curious phænomenon in the natural history of the earth, which has occafioned much difcuffion, and continues ftill the fubject of enquiry, is the regularly formed bafaltes. It was almost decided that it was a rock melted and cryftallized in this peculiar form, when two German chemifts, M. M. Werner and Wedenman, discovered a mafs of bafaltes refting on coal. This the editor of the Journal de Phyfique explains,

In another memoir of M. Werner, which we have feen fince writing the above, he mentions an argument of fomewhat more force, viz. his having obferved a bafaltic rock refting on clay, fand, and wache. From this allo he concludes, that bafaltes are the production of water. But it is well known that a part of the bafaltic mountain in the north of Ireland refts on a calcareous ftratum, and this proves only that bafaltes is a production, poftcrior to the formation of ftrata in confequence of depofition from water.

by fuppofing that water is effential to the formation of bafaltes, and confequently the cooling may have been too fudden to admit of the deftruction of the coal. This anfwer we cannot admit, for a regular cryftallifation is in every inftance inconfiftent with rapid cooling. It is more probable, allowing the fact, which is not, however, very clearly stated, or unexceptionably fupported, that lava falling in a melted state on a bed of coal, and immediately excluding the air, would affect the coal only to a certain distance, whofe afhes would combine with the lower lamina of the melted mass. Or it may have happened, that the coal was formed subsequent to the bafaltes, as baron Born found veins of coal in the retractions of a com❤ mon lava.

M. Dolomieu has confidered this fubject in general, instead of answering the German mineralogifts more particularly, and his memoir deferves attention, as it contains fome very important obfervations on bafaltes. It is introduced by a defcription of what has been called the Egyptian bafaltes, a stone very hard, black, and greatly prized for its durable nature, and the high polifh of which it was capable. It was the subftance of many ancient works in ftatuary, and was brought from Ethiopia: it is ftyled by Strabo and Herodotus lapis Ethiopicus, and it is faid to equal iron in hardness. Many works in this stone remain, which M. Dolomieu, after a careful examination, thinks are not volcanic, with the exception. of a single statue of the Villa-Borghese, covered with hieroglyphics, and formed of a black lava pierced with numerous little pores. The other black stones belong to the trapps, the fchorls in mafs, rarely finely grained, but often of a scaly texture, like the hornblend.

The most frequent of these black stones are granites, in which the black fcaly fchorl predominates fo much as to give them their particular colour, while the white fpar is united fo fparingly, and in fuch minute threads, with the rest of the mafs, or in fuch transparent particles, as to be almost invisible. In reality, he adds, the black compact lavas resemble so closely the trapps, and the natural horn-ftones, as to be indiftinguithable by external characters, and even by analyfis: a careful and scientific examination of the furrounding country is often alone able to determine the difference; for lavas often preferve the grain, colour, texture, and other external characters of the rocks from which they are formed,' without any addidition or diminution; refembling rather the fusion of metals than any other effect of fire. It was our author's opinion in his former work, his Defcription of the Pontiæ Infulæ, that bafaltes was the effects of the lava being cooled by water, or as he paradoxically expreffes himself, the regular retraction of

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the prifms is the effect of the fudden cooling. The trapp, or the fchorl in mafs, is not, he thinks, the only earth which in cooling affumes this form, as every kind of lava is occafionally cryftallised in the fame way; and earth crystallifing from a watery folution, as the volcanic tufa of the Campagnia of Rome, will occafionally affume the prifmatic form. On the whole, he concludes, that bafaltes is a vague indeterminate term, leading to no certain conclufion; that the appellations should be prifmatic and globular lavas, while the regularity of form, though most commonly depending on a cryftallzation, in confequence of fufion, may fometimes happen when the fluidity is occafioned by folution; and in neither inftance is the form. connected with ftones of a peculiar nature.

Such are M. Dolomieu's ideas; and as he has attended clofely to the effects of fire in volcanic countries, his obfervations deferve much attention. Long before the publication of his work on the Infulæ Pontiæ, we fuggefted the fufpicion, that the fimilarity of the trapps to the bafaltes arofe from the fufion taking place in the bowels of the earth, and the little change that could in such a fituation take place in the ingredients. But that the regular cryftallization can be owing to the rapid cooling, is repugnant to every other chemical fact, and it is repugnant to obfervation, which fhows that bafaltic columns are often found where water could not probably have been at the period of their formation. In fhort, though the different facts recorded add to our knowledge of nature, and the changes that have taken place on the globe, they fcarcely improve the philofophy of this branch of natural hiftory.

There is one part of this fubject which, if well founded, will materially influence the fyftems of cofmogony; and it is a fact which we have formerly alluded to, viz. the reduction of some of the earths to a metallic ftate, which were fuppofed not to have the flightest connection with metals. We fometime ago mentioned that the calcareous earth, magnefia, and the earth of alum, had been apparently reduced, and we added foon afterwards, that the experiment was found to be fallacious. In fact, M. Klaproth afferted, that the pretended reguli were only fiderite, formed by phosphoric acid in the charcoal, joining with fome irn on the Heffian crucible. He challenged the authors M.M. Tondi and Riprecht to the trial: they accepted the challenge; no earth was added, and no regulus was produced. M. Klaproth was feemingly defeated. Since that time, chemifts have been divided in opinion, but the best appeared to lean to the fyftem of M. M. Tondi and Ruprecht. In this fituation we fhall give the refult of experiments made to a greater extent, and with a more exact attention. From a view of thefe,

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there will be little neceffity of our deciding either in favour of, or against their authenticity.

The author of the memoir, whofe fteps we fhall follow in this account, is M. Tihaufky, firft lieutenant of the imperial founderies, who introduces his obfervations by remarking, that the apparent utility of this discovery, and the natural defire of extending his knowledge, led him to repeat M. Tondi's experiments: that chemist had himself repeated the experiments before M. Tibauíky, in the public laboratoty at Vienna. The firft objects of our prefent author's refearches were the tungftein and molybdena: but on these subjects he has added nothing new. Our principal attention must be directed to the pretended reduction of the fimple earths.

The calcareous earth was put into a Heffian crucible, after being formed into a paste with linfeed oil and charcoal, covered with bones well calcined and washed, to prevent the access of air. The fire was raised tothe greatest height, and continued above half an hour. The metal obtained, in colour and brilliancy refembled platina. Its texture was granulated, and when broken appeared like fteel. The line which it formed on the touchstone refembled, in its grey whitenefs, that made by. platina. It was brittle, fufceptible of a beautiful polish, and magnetic only, when broken down to a powder. Four grains and a half of metal were produced from 100 of pure earth, and its specific gravity was 6.571. M. Tondi called it parthenium.

The metal obtained from magnesia, treated in the fame manner, was of a cinereous colour, refembling martial platina: it in other refpects refembled the parthenium: from 100 grains of earth 3 of metal were only procured, of a specific gravity. equal to 7.380. This M. Tondi called auftrum.

From the barytic earth in a very pure ftate, treated in the fame way, a metal very fimilar to the auftrum was procured. From 100 grains of earth 4 grains of a metal of a specific gravity equal to 6.744 was produced, which was ftyled borbonium.

The metal obtained from earth of alum refembled fteel in colour, with reddifh fpots. Its texture was alfo granulated, and it broke with the greyish colour of fteel. In other refpects it refembled the former metals, affording 7 grains from 100 of the earth, of the fpecific gravity of 6.184.

From thefe facts it will appear, that the new metals greatly re 'emble each other, which leads us to think that they are produced from one common fubftance. It is remarkable alfo, that no metal is produced if all communication of air is taken away; and in a larger crucible or a lefs violent fire, thofe portions of earth contiguous to the crucible are only reduced. Befides, all the metal procured, not magnetic, was in fo minute a quan

tity, and with such different appearances, as plainly to indicate fome other fource; and in the fcoriæ glass was almost always found, refembling that which is, in other operations, procured from the fame earths. To this it may be added, that, as in all thefe experiments the metal in the crucible, at least on its internal fubftance, muft be reduced, the metal found in thefe proceffes fhould, in every inftance, be a mixed one. This led our author to a feries of experiments, in which he discovered that the crucible alone afforded iron; but when the process was conducted with powdered bone, the metal was only magnetic in its divided state. The refults then in these different experiments was truly fiderite: the appearances which we have mentioned fupport this resemblance, and the chemical qualities which, to fhorten our account we have not noticed, are thofe of fiderite only. The earth of borax, alfo, which was reduced in M. Tondi's experiments, refembled these metals which we have defcribed; and as calcined bones were effential to the fuccefs of the procefs, we must fuppofe the fource was the fame.

There has been a more recent discovery in Cornwall of an earth apparently metallic, of which we can only give an imperfect account from a foreign Journal. It is with regret that we perceive no work in this kingdom which conveys an early account of fuch discoveries, or that our offer of configning a few pages of this Journal for the purpofe has been overlooked. Mr. W. Gregor is faid to have found an earth at Menackanite in Cornwall, refembling gunpowder. It diffolves in the vitriolic acid, and the folution is yellow. If bright iron is added it affumes a reddish colour refembling amethyfts. Phlogisticated alkali added to this martial amethyftine folution precipitates a yellow white powder; and tincture of galls gives the fame folution an orange colour. If the nitrous acid is added to the amethiftine folution, and to the folution changed by the galls, the first affumes a blue colour, and the fecond a black. Manganefe produces nearly the fame effects on thefe two liquors. (To be continued occafionally.)

MONTHLY

CATALOGUE.

DIVINITY, RELIGIOUS, &c.

The Meaning which the Word Myftery bears in the New Teftament, confidered and applied, in a Sermon preached to an Assembly of Minifiers. By J. Toulmin, M. A. 800. Is. Johnfon. 1791. Tis Mr. Toulmin's object to show, that, in the New Testament, what has been concealed, and is afterwards explained, is ufually called a mystery; and his chief conclufion is, that no

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