ever, to be very imperfect, as Mr. Kirwan has clearly shown. Another experiment relates to the different phænomena of glass, when cooled after melting, either slowly or rapidly: in the first case, it loses all its vitreous properties, and becomes opake, white, and refractory; in the second, it resumes them. In fact, in the former instance, the glass is decomposed; the flint separates, and gives the milky colour, in consequence of the volatilisation of some of the alkali: in the latter, there is no time for the separation of the flint to take place.

Granite is an aggregate stone consisting of quartz, felspar and mica; of these the most fusible is undoubtedly the felspar, and the quartz the least; let us then to indulge the worthy baronet suppose all three in perfect fusion in a high degree of heat, and afterwards slowly cooled, and thus each (though vouched by no experiment) gradually reproduced; the quartz, with the exception of the proportion thereof which enters into the composition of felspar and of the mica would undoubtedly crystallize first on the smallest diminution of heat, and, being congealed in a medium still in a liquid state, I do not see why it should not form regular crystals, which nevertheless scarce ever occur in granite except in cavities. Over this, and after a considerable interval of time, the mica should also be regularly crystallized, and last of all, the felspar should coalesce and congeal, (at least in the baronet's supposition) in regular crystals; now as the crystallisations of these three species of stone take place each at a distinct portion of time, each should occupy also a distinct portion of space, the first set of crystals being lowest, the next over that and the last uppermost, as we find to happen when salts of very different solubility and yet in equal quantity are dissolved and crystallised in water, or when substances of different degrees of volatility are sublimed by fire. Now, among the immense masses of granite that have been observed and examined in various parts of the globe, not above half a dozen have occurred in which the three constituent parts of granite were regularly crystallized, very few in which distinct layers of each were seen, and none at all consisting of distinct regular crystals of each, superimposed on each other. On the contrary in far the greater number of granitic masses the three above named constituent masses lie intermixed with each other in the most confused and irregular manner, and without any appearance of regular crystallization; insomuch that none can say, from bare inspection only, which was crystallized first, and which last,-nay granitic masses not unfrequently occur, in which it is evident that the mica must have crystallized contemporaneously with the quartz, for in breaking the quartzy part flakes of mica are found within it. See 6, Sauss. § 1621.

Lastly, I must add, that even on the supposition that distinct crystals of quartz, felspar and mica could be produced by fusion, they still would be far from resembling those we are acquainted with, which essentially contain some particles of water, as I have elsewhere shewn,' P. 9.

Some other very decisive observations on this subject follow, on which we need not enlarge. Indeed, we are less inclined to

do so, as our ideas of the formation of granites differ from those of Mr. Kirwan; and we have already stated our leading principles in reviewing that author's Essays.

The experiments published more lately are next the object of Mr. Kirwan's remarks. Grunstein was first vitrified by a strong heat, and rapidly cooled. It was first softened, and then soon became hard; at least, it was found to resemble porcelain, and to be more refractory than before. When this glass was cooled slowly, it looked like whinstone: the fracture, instead of being partly striated, and partly foliated, was rough, stony, and crystalline, with a number of shining facettes intermixed, and a few crystals in the cavities, produced by the airbubbles. In these experiments, Mr. Kirwan shows very satisfactorily that some decomposition actually takes place in the first instance; and, in the second, that it is not a vitrification, but a change to a kind of enamel, the nature of which he explains. We should add, that the circumstance of the cavities would be decisive, as they are never found in whinstone, so that it could not be volcanic. The shining facettes are only incipient crystallisations, when the affinity of the alkali is lessened, and the earths begin to assume their solid form. But, notwithstanding these appearances, the distinctions between natural whins and these artificial ones are so striking, as to leave no difficulty in the decision. The second criterion we have long since pointed out, as a decisive mark of distinction between traps and lavas.

1o The natural whins, particularly amygdaloids (vulgarly called toadstones) frequently contain calcareous spar and zeolyte; now as the former contains fixed air, and the latter a notable proportion of water, I hardly think sir James, who professes not to agree with Dr. Hutton in all points, will allow these to have been vitrified or fused.

20 The natural whins, according to Dr. Kennedy's statement, lose five per cent. of water and other volatile matter when heated to redness. It is not said whether the artificial lose any part of their weight by such treatment, but it is plain they would not, since even the lavas of Catania and Piedemonte, though of ancient date, lost none, as Dr. Kennedy expressly notices, and has thus afforded an excellent criterion for distinguishing the long contested origination of these substances.

3° As sir James has neglected giving a complete account of the external characters of the natural whins, which were the subject of his experiments, as also of the regenerated or artificial whins derived from them, and as I have not myself seen them, it is difficult for me to compare them with each other, and would indeed be impossible if some account of them had not been given by Mr. Pictet in his valuable Journal Britannique, copied into the 5th vol. of the new Rozier's Journal, p. 313. It is the result of the examination both of the natural and artificial whins by the Society of Natural History at Geneva.

As to the natural grunstein, No. 1, they remark that it betrays

not the least mark of an igneous origin, but that the whins which sir James produced from it had every distinctive character of a lava, and even of a porous lava.

The basalt (or rather trapp) on which the castle of Edinburgh stands is of a compact structure; the art ficial produced from it, sir James tells us, so greatly resembles it both in colour and texture that it would be difficult or perhaps impossible to distinguish them, but for a few minute air bubbles, distinguishable in the artificial. Neptunists will however consider this as a leading character of distinction. The mineralogists of Geneva add, that the colour of the artificial is deeper, and its hardness greater than that of the natural. If the specific gravity and other characters of both were given, it is probable that other differences might be perceived. It is only in these characters that any difference can be expected, as the internal composition must be the same in both.

Of the remaining artificial whins I can give no account, their external characters having been omitted; I cannot however pass over the general inferences that sir James deduces from his experiments, namely, "that the arguments against the subterraneous fusion of whinstone, derived from its stony character, scem now to be fully refuted,” for not to repeat what has been already said, that many of them contain substances whose existence is incompatible with that hypothesis, I must farther add that the upright state in which many of them exist, for instance, the basaltic pillars of Staffa, and of the Giants Causeway, and of many other countries, the basis they rest on, sometimes granite, sometimes gneiss, sometimes coal or limestone, and the total absence of all signs of the operation of fire, forbid us to entertain any doubt of their production in the moist way. Nay the college of Dublin now possesses fragments of basaltic pillars in which marine shells are imbedded; if such evidence can be resisted it is in vain to seek for greater.' P. 23.

II. An Illustration and Confirmation of some Facts mentioned in an Essay on the primitive State of the Globe. By Richard Kirwan, Esq; LL.D. F. R. S. and P. R. I. A.'

Our author, in a former essay, had contended that some portion of land had probably emerged from the waters, before the creation of fishes. This position has been denied. In proof of the Mosaic account, Mr. Kirwan alleged that no petrifactions were found incorporated in masses of stone, in countries elevated more than 8500 or 9000 feet above the actual level of the sea. Since that time, it has been asserted, by the author of the Histoire du Monde primitif, that Don Ulloa. found shells imbedded in stones, at the height of 14220 feet above the level of the sea in Peru; and Don Ulloa has asserted the same in his late work-Mémoires philosophiques, &c. It is, then, Mr. Kirwan's object to show, that, in reality, the spot alleged is not nearly so high; or, whatever be its height, that these shells are the remains of the deluge. The former point is rendered highly probable, by comparing the different parts of the description; and the error is supposed to be derived from a

mensuration of the height by the barometer. Quicksilver was not, at that time, purged of air, by boiling in the tube; and a very little air remaining, would expand greatly at that elevation, and proportionally depress the mercury. The place where the shells are found cannot, when the requisite deduction is made, be more than 8200 feet above the level of the sea. The second position is proved, by petrified wood being traced with the shells; and La Pérouse, who found shells on Mont Perdu, at the height, it is said, of nearly 10,000 feet, found with them also the petrified bones of marine animals.

III. An Essay on the Declivities of Mountains. By Richard Kirwan, Esq; LL.D. F.R. S, and P. R. I. A.'

This is a very curious paper. The western sides of moun tains are, in general, the steepest, when the mountain runs cast and west; and the southern, of those that run north and south. These particulars our author explains very minutely, from the double motion of the ocean; viz. that from east to west, the present course of the tides; and the other from north to south. As, from its extent, we cannot enter into the detail, our objections to this second direction of the currents must be reserved till some future opportunity. We have often suggested, in this journal, that the direction of the bays, and inland seas, seems rather to show a motion from the equator to either pole; and this motion, combined with, or in opposition to, that of the tides, will, we think, explain all the varieties met with more satisfactorily than our author's system. The whole of this essay is particularly ingenious and scientific.

IV. Of Chymical and Mineralogical Nomenclature. By Richard Kirwan, Esq; LL. D. F. R.S. and' P. R.I. A.'

Mr. Kirwan's remarks are chiefly designed as a defence of his own nomenclature, and a reply to the objections offered by the French chemists to his changes. We fully agree with him in one point, that the changes have been too general and too rash. Like brother Jack, in tearing off the lace, they have injured the cloth; and, to be as unlike that rogue Peter as possi ble, they have assumed a new garb, which requires years to study. When learnt, another lesson will remain; viz. to re-acquire the language which they have thus supplanted; or the works of Stahl, Beecher, and Boyle, with all the chemists of the old school, must be renounced. We have already noticed this subject, however, in our review of the new edition of the Edinburgh Phar macopoeia, which has lately reached us; where Herod is outHeroded, and reform is carried to its highest pitch-almost, indeed, to the confines of confusion. Mr. Kirwan's remarks are highly proper; and, but that they would lead us too far, might be the subjects of some particular observations. But while we admit the merit of these remarks, and, in general, of Mr. Kirwan's improvements of the nomenclature, we may be CRIT. REV. Vol. 38. August, 1803.

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allowed to question their expediency; and, while the French school of chemistry, with its language, retains its power, it may perhaps be better to err with this establishment, than to be right alone. To be generally intelligible, we should use common language.

V. A Description of a reflecting Level or an artificial Horizon for taking Altitudes of the celestial Bodies, &c. on Land by Hadley's Quadrant, with some Remarks on different Levels. By the Rev. James Little.'

The principle of our author's improvement is the adaptation of an artificial level to Hadley's quadrant, to take altitudes on land. In using it at sea, the water affords the level. The instrument is ingeniously contrived, and promises to be highly useful. It is impossible to convey an adequate idea of it without the plate.

VI. On the Naturalization of Plants. By John Templeton, A.L.S. Communicated by the Bishop of Clonfert.'

Our author gives some highly-proper and judicious directions respecting the method of naturalising plants to soils and temperatures different from their own. These we cannot abridge; but may femark-what our author has perhaps not so fully insisted on as he might that plants may be rendered capable of sustaining considerable degrees of cold. Cold alone is seldom very dangerous; but the bad effects arise from cold succeeding a moist or rainy period. We have seen geraniums bear the winter without shelter, by only covering the earth around with a perforated board, to admit the rain but sparingly. Mr. Templeton has not, however, wholly omitted this part of the subject; and we shall select what he has said respecting climate.

The laurustinus is one of those plants that were introduced to Ireland before green-houses were known, consequently planted in the open ground, and experience shews that it is seldom hurt by frost. By it we find that some plants, which to appearance are not fitted for our climate, do yet outlive our winters; and that, without a knowledge of their native stations, we may sometimes suppose plants to be tender which are really hardy: thus the laurustinus is unhurt by frost in Ireland until the cold exceeds that of its own climate. The buddlea globosa and fuschia coccinea are other instances of plants, that without a knowledge of their native climate, Chili, we would not suppose capable of being naturalized to ours. Yet is the buddlea seldom injured by our cold, and the fuschia, although killed to the ground by the winter's cold, sends forth abundance of shoots which attain the height of three feet in summer, and are decorated with its elegant flowers, which are larger and much more brilliant than ever they are when confined in a house.

And there is little doubt but [that] many plants of Chili, and even those which grow within the tropics, when found near the elevation of perpetual frost, would bear the cold of Spitzbergen; for on the tops of mountains are found the plants of the plains of more northern latitudes. Thus is the salix herbacea of Lapland and Spitzbergen found