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philosophers, it aslifts the cause of revelation; and this we have always studiously pointed out, though we have given offence by not believing more than revelation ever taught. Mr. Kirwan's system, in a more popular form, occurred to our notice in the sixth volume of the Irish Transactions *, and we there paid it the tribute of applause which it so truly deserved. The fame system is contained in the three first eflays of the present volume, nearly, we believe, in the same words. We shall not, therefore, repeat his former facts and arguments, but offer fomewhat more at large our observations on granite and the effect of compound menstrua, which the author has not, in our judgement, followed with sufficient accuracy.
We were always of opinion, that, if a chaotic fluid were supposed, the separation of these confusedly mixed parts mult, from their nature, be in the order, pointed out by the Mosaic account; and, conversely, the present state of the globe de monstrates very clearly that such a fluid must have existed. One striking argument for this position is, the peculiar structure of granite, undoubtedly the most copious production of the earliest æras of this globe's arrangement. No mineralogist has hitherto explained its formation satisfactorily, and we think even Mr. Kirwan fails in the present attempt. He confiders the crystallisation of its component parts to have been fuccessive, and, as we before observed, eludes the great difficulty felt by his predecessors, who knew not where to seek for the quantity of water necessary to dissolve the quartz, by supposing that a less proportion would keep it diffolved than is necessary at first co diffolve it. The minute inixture, however, of the feltspar and mica destroys every idea of successive crystallisations, and every appearance of granite Thows its formation to have been rapid and almost instantaneous. The crystals are regularly intermixed, with little or no water of crystals lisation, and the whole is a mass of considerable specific gravity.
The immediate consequence is, first, that the component parts of granite must have been held in solution by a menftruum which was suddenly destroyed or greatly diminished; or, secondly, by a compound menstruum, of which the union and the powers were at once dissolved and loft. We can conceive of no cause of the foriner nature; but we have every reason to fuppose that the chaotic fluid may have contained a menstruum which will meet the latter supposition. We kuow, for instance, that carbonic acid air will facilitate the action of water on quartz: we know too that lime will destroy the union between quarız and the alkali in liquor filicum. The rapid feparation of the former, or the addition of the latter, is alone necessary. Nor was this the operation of a moment: the pro
* See our XXVIIIth Vol. New Arr, p. 414,
ducion of granite is succeslive, and Saufsure has pointed out granite which must be of modern formation. We fee it to be Tuccessive in the veined granite; and nodules of granite are often inclosed in immense blocks. Was Mr. Kirwan's opinion correct in these last, the quartz, as the lefs soluble material, and consequently most readily crystallised, should surround the nucleus, and the mixture of felispar and mica appear in suc'ceflio!. But this is not the case: the whole is a confused mass. 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 discussion ; nor thould we have at all engaged in the detail of this subject but to offer fome foundation for our differing from an authority so truly respectable as that of Mr. Kirwan. We shall add the conclusion of the first essay.
• Here then we have seven or eight geological facts, related by Moses on the one part, and on the other, deduced solely from the most exact and best verified geological obfervations, and yet agreéing perfectly with each other, not only in substance, but in the order of their succession. On whichever of these we bestow our eonfidence, its agreement with the other demonstrates the truth of that other. But if we bestow our confidence on neither, then their agreement must be accounted for. If we attempt this, we fall find the improbability that both accounts are false, infinite; confequently one must be true, and, then, so must also the other,
. That two accounts derived from sources totally diftinct from and independent on each other fhould agree not only in the fub. stance but in the order of succession of two events only, is already highly improbable, if these facts be not true, both substantially and as to the order of their succession. Let this improbability, as to the fibítance of the facts, be represented only by ts. then the improbability of their agreement as to seven events is - , that is, as one to ten millions, and would be much higher if the order allo had entered into the computation.' P. 52. - In the second essay, on the deluge, our author notices the most important syitems, particularly that of M. De Luc, who thinks that, in this memorable catastrophe, the former contie nents became the bottom of the sea, while the ground that the antediluvian ocean covered produced the continents of this period. Mr. Kirwan thinks the deluge was universal, and, as we have said, from the Southern Ocean bursting over the northern continents; and that ravenous and noxious animals were created subsequent to the flood. At that time he believes the animal tribes to have been few, and of a milder nature. On this fubject we suspect his syileın to be erroneous; and fhall thorily have an opportunity of explaining ourselves more at large.
The third essay, on the subsequent catastrophes, does not materially differ from our author's communications in the Irish Transactions. We greatly regretted our not being able to follow Mr. Kirwan's observations more minutely at that time. It would be still more improper now.
The fourth essay is on lapidification. Substances acquire a ftony hardiness from crystallisation, a more or less perfect or confused concretion, cementation, or the substitution of unorganic to organic matter. These different causes are examined in their order. Crystallisation is probably the mode in which the most stony and'impenetrable rigidity is obtained, and probably in this way ttucco attains its peculiar hardness, in which it eniulates the firmest marbles. Perhaps the very minute union of the ingredients which form the different precious stones arises from their crystalliling lowly from a ftate of perfect solution. Mr. Kirwan has, we think, proved, that even in water filex may be dissolved ; add it is not improbable that the division of the particles of a body, with difficulty soluble, is more minute than that of the particles of a more Soluble body. The other methods of lapidification offer no. thing remarkable. Those who have visited the shores of the sea will have beheld numerous instances of cementation, or rather agglutination. The farne method occurs also, without the aslistance of sea water, sometimes by calces of iron, somne times by river water, which perhaps may deposit flinty concretions. The agent is, however, not understood in every inItance.
The fifth essay, on the decomposition and disintegration of stony substances, is very copious and valuable. The following circumstance, in the stone at Malta, requires a little ate tention.
• Carbon has lately been found in several species of stone; as it powerfully attracts oxygen, to it we may, perhaps, attribute the disintegration of many of them, as marls, marlites, some, argillites, Thales, &c.
Mephitic air (the azote of the French) by its property of forming nitrous acid, when, during its nascent state, it is gradually brought into contact with the oxygen of the atmosphere, in a moderately dry ftate, may also promote decomposition ; calcareous stones are known to contain it in pretty considerable proportion, and those that contain animal remains, probably, most; from this consideration we may derive fome explanation of a very remarkable phenomenon related by Mr. Dolomieu. 36 Roz. 116. " All the houses of Malta are built of a fine grained limestone, of a loose and soft texture, but which hardens by exposure to the air. There is a circumstance which bastens its destruction, and reduces it to powder, namely, when it is weited by sea-water; after this it never dries, but
is covered by a saline effervescence, and a crust is formed some tenths of an inch thick, mixed with common salt, nitre, and nitrated lime ; under this crust the stone moulders into duft, the crust falls off, and other crusts are successively formed, until the whole stone is destroyed. A single drop of sea water is sufficient to producet germ of destruction; it forms a spot which gradually increases and spreads like a caries through the whole mass of the stone; nor does jt stop there, but, after some time, affects all the neighbouring stones in the wall. The stones most subject to this malady are those that contain most magnesia; those which are fine grained, and of a close texture, reist most.” Short as this account is, it appears from it, that the limestone of Malta contains both calcareous earth and mag. nesia, but most probably in a mild ftate; and the stone being of the loofer kind, is of the species which is known to contain most mephitic air. Mr. Dolomieu Thews, at the end of his tract on the Lipari islands, that the atmosphere of Malta, in some seasons, when a south 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, sea water, besides common salt, contains a notable proportion of muriated magnesia, and a small proportion of selenite. From these data we may infer, that, when this stone is wetted by sea water, the selenite is decomposed by the mild magnesia contained in the stone, and intimately mixed with the calcareous earth; of this decomposition, two results deserve attention, 1. The production of vitriolic Epsom ; 2. The extrication of mephitic air, the muriated magnesia of the sea water serving, during this extrication, the purpose of attracting and detaining a sufficiency of moisture. This air, thus Nowly generated, and meeting the dry oxygen of the aimosphere, forms nitrous acid, highly mephitised, but it soon acquires a due proportion of oxygen by deoxygenating the vitriolic contained in the Epsom salt, which by successive depredations of this sort is gradually destroyed. Part also must unite to the mild calx, which in its turn is decomposed by the remaining mild magnesia; more mephitic air is fet loose, and more nitrous acid is produced, until the stone is destroyed; 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 mysterious; Is it not from the tartarin lately discovered in clays and many stones? I am as yet inclined to think that it is derived from the putrefaction of vegetable and animal sub. stances; and though nitrous acid formed of oxygen and air, from putrefying substances, be found united, not only to the absorbent earths to which it is exposed, but also to a fixed alkali; yet I thould rather suppose that the alkali is conveyed into those cartbs by the putrid air, than newly formed; and the reason is, that tartarin, notwithstanding its fixity, is also found in foot, and in the same man. ner may be elevated in putrid exhalations. As to the common salt, said also by Dolomieu to be found in the blisters of this mouldering ftone, I am as yet in doubt, for common salt was also said to accompany the native nitre found in the pulo of Appulia, yet Klapa roth in analysing this nitrated earth could find none; see Zimmerman's account of this native nitre. 36 Roz. 111. 113, and 1 Klap. 319. p. 147
Some late discoveries of Guyton will come in aid of this very ingenious explanation ; and, if confirmed, will greatly illustrate every part of Mr. Kirwan's doctrines. He has found, it is said, shat potash is composed of limestone, hydrogen, and carbon; soda of magnefia and the same principles. If this be true, the source of the alkali in this case and the nitre beds is at once clear; and as soda, either as fimple or in its compound rate, is a primæval substance, a folution of Aint and a ready precipitation in the form of granice, as just alluded to, is easily understood. The various agents which disintegrate stony substances are water, oxygen, and fixed air. Granites are only decomposed by water washing away the feltspar, and leaving the quartz in a carious state with few points of union. It is then called in the manufactories rotten ilone.
Mr. Kirwan next treats of mountains, but considers them, we think, too exclusively, as owing to precipitation. They are so very frequently, and, as we shall find, were at an earlier period higher than at present, while the valleys were deeper. Yet many of them are raised; and he will recollect more than one observation in Saussure, where the secondary mountain has been raised with the primary on which it rested, after the formation of the former in horizontal strata. We admit, however, that volcanos have been too frequently considered as the cause by which mountains have been elevated. The primicive mountains are accurately described, and it is now well established that there are primæval calcareous mountains, Yet the calcareous earth, in granite, appears an accidental ad. dition; and though this earth is primæval, with respect to ani. mals and vegetables, it is probably of posterior formation to granite, which seems to be contcmpoi aneous with the existence of fixed air.' Mr. Kirwan next examines particularly the different stones of which mountains contift; but thele details are too scientifically mineralogical for our present purpose. The eleventh section on trap must, however, be distinguished. It is the last refuge of the volcanic systems, and is clearly thown not to be volcanic. Mr. Kirwan next treats of the secondary and alluvial mountains. In these, trap again occurs; for it is sometimes secondary, though never the product of fire. To fhow the structure of the secondary mountains, containing more than one kind of stone, an enumeration of the strata of such mountains in different places is added. The third chapter of this essay is on volcanic mountains; but