philofophers, it affifts the cause of revelation; and this we have always ftudiously pointed out, though we have given offence by not believing more than revelation ever taught. Mr. Kirwan's fyftem, in a more popular form, occurred to our notice in the fixth volume of the Irish Tranfactions *, and we there paid it the tribute of applause which it fo truly deferved. The fame system is contained in the three firft effays of the prefent volume, nearly, we believe, in the fame words. We shall not, therefore, repeat his former facts and arguments, but offer fomewhat more at large our obfervations on granite and the effect of compound menftrua, which the author has not, in our judgement, followed with fufficient accuracy.

We were always of opinion, that, if a chaotic fluid were fuppofed, the feparation of thefe confufedly mixed parts must, from their nature, be in the order pointed out by the Mofaic account; and, converfely, the prefent ftate of the globe demonftrates very clearly that fuch a fluid must have existed. One ftriking argument for this pofition is, the peculiar ftructure of granite, undoubtedly the moft copious production of the earlieft æras of this globe's arrangement. No mineralogift has hitherto explained its formation fatisfactorily, and we think even Mr. Kirwan fails in the prefent attempt. He confiders the cryftallifation of its component parts to have been fucceffive, and, as we before obferved, eludes the great difficulty felt by his predeceffors, who knew not where to feek for the quantity of water neceffary to diffolve the quartz, by fuppofing that a lefs proportion would keep it diffolved than is neceffary at firft to diffolve it. The minute mixture, however, of the feltfpar and mica deftroys every idea of fucceffive crystallifations, and every appearance of granite fhows its formation to have been rapid and almoft inftantaneous. The crystals are regularly intermixed, with little or no water of cryftal lifation, and the whole is a mafs of confiderable specific gravity. The immediate confequence is, firft, that the component parts of granite must have been held in folution by a menftruum which was fuddenly destroyed or greatly diminished; or, fecondly, by a compound menftruum, of which the union and the powers were at once diffolved and loft. We can conceive of no caufe of the former nature; but we have every reason to fuppofe that the chaotic fluid may have contained a menftruum which will meet the latter fuppofition. We know, for inftance, that carbonic acid air will facilitate the action of water on quartz: we know too that lime will deftroy the union be tween quartz and the alkali in liquor filicum. The rapid feparation of the former, or the addition of the latter, is alone neceffary. Nor was this the operation of a moment: the pro

* See our XXVIIIth Vol. New Arr. p. 414.

du&ion of granite is fucceffive, and Sauffure has pointed out granite which must be of modern formation. We fee it to be fucceffive in the veined granite; and nodules of granite are often inclofed in immenfe blocks. Was Mr. Kirwan's opinion correct in thefe laft, the quartz, as the lefs foluble material, and confequently moft readily cryftallifed, should surround the nucleus, and the mixture of feltfpar and mica appear in fucceffion. But this is not the cafe: the whole is a confused mafs. We thus give the outline of our opinion, which may be fupported by numerous arguments and observations, but it will be obvious that this is not the proper place for such a difcuffion; nor should we have at all engaged in the detail of this fubject but to offer fome foundation for our differing from an authority fo truly refpectable as that of Mr. Kirwan. We fhalb add the conclufion of the firft effay.

Here then we have feven or eight geological facts, related by Mofes on the one part, and on the other, deduced folely from the moft exact and beft verified geological obfervations, and yet agreeing perfectly with each other, not only in fubftance, but in the order of their fucceffion. On whichever of thefe we bestow our eonfidence, its agreement with the other demonftrates the truth of that other. But if we beftow our confidence on neither, then their agreement must be accounted for. If we attempt this, we fhall find the improbability that both accounts are falfe, infinite; confequently one must be true, and, then, fo muft alfo the other.

6

That two accounts derived from fources totally diftinct from and independent on each other fhould agree not only in the fubftance but in the order of fucceffion of two events only, is already highly improbable, if thefe facts be not true, both fubftantially and as to the order of their fucceffion. Let this improbability, as to the fubftance of the facts, be reprefented only by. then the improbability of their agreement as to feven events is

1° 7 10679

that is, as one to ten millions, and would be much higher if the order also had entered into the computation.' P. 52.

In the fecond effay, on the deluge, our author notices the most important fyftems, particularly that of M. De Luc, who thinks that, in this memorable catastrophe, the former contiments became the bottom of the fea, while the ground that the antediluvian ocean covered produced the continents of this period. Mr. Kirwan thinks the deluge was univerfal, and, as we have faid, from the Southern Ocean bursting over the northern continents; and that ravenous and noxious animals were created fubfequent to the flood. At that time he believes the animal tribes to have been few, and of a milder nature. On this fubject we fufpect his fyilem to be erroneous; and fhall thortly have an opportunity of explaining ourselves more at large.

The third effay, on the fubfequent catastrophes, does not materially differ from our author's communications in the Irish Tranfactions. We greatly regretted our not being able to follow Mr. Kirwan's obfervations more minutely at that time. It would be still more improper now.

The fourth effay is on lapidification. Substances acquire a ftony hardiness from cryftallifation, a more or lefs perfect or confused concretion, cementation, or the fubftitution of unorganic to organic matter. Thefe different causes are examined in their order. Crystallifation is probably the mode in which the most ftony and impenetrable rigidity is obtained, and probably in this way ftucco attains its peculiar hardness, in which it emulates the firmeft marbles. Perhaps the very minute union of the ingredients which form the different precious ftones arifes from their cryftallifing flowly from a state of perfect folution. Mr. Kirwan has, we think, proved, that even in water filex may be diffolved; and it is not improbable that the divifion of the particles of a body, with difficulty foluble, is more minute than that of the particles of a more foluble body. The other methods of lapidification offer nothing remarkable. Thofe who have vifited the fhores of the fea will have beheld numerous inflances of cementation, or rather agglutination. The fame method occurs alfo, without the affiftance of fea water, fometimes by calces of iron, fome. times by river water, which perhaps may depofit flinty concretions. The agent is, however, not understood in every inftance.

The fifth effay, on the decompofition and difintegration of ftony fubftances, is very copious and valuable. The following circumftance, in the ftone at Malta, requires a little ate tention.

'Carbon has lately been found in feveral species of stone; as it powerfully attracts oxygen, to it we may, perhaps, attribute the difintegration of many of them, as marls, marlites, fome, argillites, fhales, &c.

เ Mephitic air (the azote of the French) by its property of forming nitrous acid, when, during its nafcent ftate, it is gradually brought into contact with the oxygen of the atmosphere, in a moderately dry ftate, may alfo promote decompofition; calcareous ftones are known to contain it in pretty confiderable proportion, and thofe that contain animal remains, probably, moft; from this confideration we may derive fome explanation of a very remarkable phenomenon related by Mr. Dolomieu. 36 Roz. 116. "All the houfes of Malta are built of a fine grained limeftone, of a loose and foft texture, but which hardens by expofure to the air. There is a circumstance which haftens its deftruction, and reduces it to powder, namely, when it is wetted by fea-water; after this it never dries, but

is covered by a faline effervefcence, and a cruft is formed fome tenths of an inch thick, mixed with common falt, nitre, and nitrated lime; under this cruft the ftone moulders into duft, the cruft falls off, and other crufts are fucceffively formed, until the whole stone is destroyed. A single drop of sea water is fufficient to producet germ of deftruction; it forms a spot which gradually increafes and 1preads like a caries through the whole mafs of the stone; nor does it ftop there, but, after some time, affects all the neighbouring stones in the wall. The ftones moft fubject to this malady are thofe that contain moft magnesia; thofe which are fine grained, and of a close texture, refift moft." Short as this account is, it appears from it, that the limestone of Malta contains both calcareous earth and magnefia, but most probably in a mild ftate; and the ftone being of the loofer kind, is of the fpecies which is known to contain most mephitic air. Mr. Dolomieu fhews, at the end of his tract on the Lipari iflands, that the atmosphere of Malta, in fome feafons, when a fouth wind blows, is remarkably fouled with mephitic air, and at other times, when a north wind blows, remarkably pure; and hence, of all others, most fit for the generation of nitrous acid.— Again, fea water, befides common falt, contains a notable proportion of muriated magnefia, and a fmall proportion of felenite. From thefe data we may infer, that, when this ftone is wetted by fea water, the selenite is decompofed by the mild magnesia contained in the stone, and intimately mixed with the calcareous earth; of this decompofition, two refults deferve attention, 1. The production of vitriolic Epfom; 2. The extrication of mephitic air, the muriated magnefia of the fea water ferving, during this extrication, the' purpose of attracting and detaining a fufficiency of moisture. This air, thus flowly generated, and meeting the dry oxygen of the atmofphere, forms nitrous acid, highly mephitifed, but it foon acquires a due proportion of oxygen by deoxygenating the vitriolic contained in the Epfom falt, which by fucceffive depredations of this fort is gradually deftroyed. Part alfo muft unite to the mild calx, which in its turn is decompofed by the remaining mild magnesia; more mephitic air is fet loose, and more nitrous acid is produced, until the stone is deftroyed; how the alkaline part of the nitre, which is one of the products resulting from the decomposition of this stone, is formed, is as yet myfterious; Is it not from the tartarin lately difcovered in clays and many ftones? I am as yet inclined to think that it is derived from the putrefaction of vegetable and animal fubstances; and though nitrous acid formed of oxygen and air, from putrefying fubftances, be found united, not only to the abforbent earths to which it is expofed, but also to a fixed alkali; yet I should rather fuppofe that the alkali is conveyed into thofe carths by the putrid air, than newly formed; and the reafon is, that tartarin, notwithstanding its fixity, is alfo found in foot, and in the fame manner may be elevated in putrid exhalations. As to the common falt, faid alfo by Dolomieu to be found in the blifters of this mouldering

ftone, I am as yet in doubt, for common falt was alfo faid to accompany the native nitre found in the pulo of Appulia, yet Klaproth in analyfing this nitrated earth could find none; fee Zimmerman's account of this native nitre. 36 Roz. 111. 113, and 1 Klap. 319.' P. 147.

Some late difcoveries of Guyton will come in aid of this very ingenious explanation; and, if confirmed, will greatly illuftrate every part of Mr. Kirwan's doctrines. He has found, it is faid, that potafh is compofed of limeftone, hydrogen, and carbon; foda of magnefia and the fame principles. If this be true, the fource of the alkali in this cafe and the nitre beds is at once clear; and as foda, either as fimple or in its compound ftate, is a primæval fubftance, a folution of flint and a ready precipitation in the form of granite, as juft alluded to, is eafily understood. The various agents which difintegrate ftony fubftances are water, oxygen, and fixed air. Granites are only decompofed by water washing away the feltfpar, and leaving the quartz in a carious state with few points of union. It is then called in the manufactories rotten flone.

Mr. Kirwan next treats of mountains, but confiders them, we think, too exclufively, as owing to precipitation. They are fo very frequently, and, as we fhall find, were at an earlier period higher than at prefent, while the valleys were deeper. Yet many of them are raised; and he will recollect more than one obfervation in Sauffure, where the fecondary mountain has been raised with the primary on which it refted, after the formation of the former in horizontal ftrata. We admit, however, that volcanos have been too frequently confidered as the caufe by which mountains have been elevated. The pri mitive mountains are accurately described, and it is now well eftablished that there are primæval calcareous mountains. Yet the calcareous earth, in granite, appears an accidental addition; and though this earth is primæval, with respect to animals and vegetables, it is probably of pofterior formation to granite, which feems to be contemporaneous with the existence of fixed air. Mr. Kirwan next examines particularly the different ftones of which mountains confift; but these details are too scientifically mineralogical for our prefent purpose. The eleventh fection on trap muft, however, be diftinguished. It is the laft refuge of the volcanic fyftems, and is clearly thown not to be volcanic. Mr. Kirwan next treats of the fecondary and alluvial mountains. In thefe, trap again occurs; for it is fometimes fecondary, though never the product of fire. To fhow the ftructure of the fecondary mountains, containing more than one kind of stone, an enumeration of the strata of fuch mountains in different places is added.

The third chapter of this effay is on volcanic mountains ; but