*

tical experiments, made with the adamantine spar, and circon (jargon of Ceylon), which, on this account, I have placed next to each other in the respective treatises. Who, for example, would have imagined, that the application of caustic alkali in the liquid state should so exceedingly facilitate the opening of hard stony matter, and remove the greatest part of the difficulties with which I had to struggle, when employing the same separating medium in the dry state?

As many persons think that the preparation of a perfectly pure caustic lye is subject to more difficulties than it really is, I will here briefly state my method of preparing it. I boil equal parts of purified salt of tartar, (carbonat of pot-ash, or vegetable alkali prepared from tartar) and Carrara marble, burnt to lime, with a sufficient quantity of water, in a polished iron kettle; I strain the lye through clean linen, and, though yet turbid, reduce it by boiling, till it contain about one half of its weight of caustic alkali; after which I pass it once more through a linen-cloth, and set it by in a glass bottle. After some days, when the lye has become clear of itself, by standing, I carefully pour it off from the sediment into another bottle. To convince myself of its purity, I saturate part of it with muriatic or nitric acid, evaporate it to dryness, and re-dissolve it in water. If it be pure, no turbidness will take place in the solution. The quantity of caustic alkali, which this lye contains, I ascertain by evaporating a certain weighed portion of the lye to dryness, in an evaporating dish of a known weight. I also take care, in the preparation of this caustic lye, that the alkali be not entirely deprived of carbonic acid; because, in that case, I can, with greater certainty, depend on the total absence of dissolved calcareous earth. By employing burnt marble, or, in its stead, burnt oyster-shells, I avoid the usual contamination of the caustic lye by aluminous earth; because lime, prepared from the common species of lime-stone, is seldom entirely free from argil.' P. vii.

The vessels must be carefully made. Even platina is attacked; and the purest silver will sometimes lose little scales. in the operation, which will give illusive appearances to the result of the process. The method of making the pure caustic alkali is a valuable one; but we have transcribed it already.

The first essay is on the habitudes of various species of stones and earths in a porcelain furnace.' The facts are chiefly important, as they destroy the usual classification into fusible and infusible earths; for many are fusible only in consequence of their containing extraneous substances, particularly iron.

Besides, the trials made with fire may be of some utility with regard to those fossils, concerning which the opinions of the learned are yet divided, with regard to the means employed by nature for their formation. I even think, that in this branch of geological researches, the experiments made by means of fire, are rather more decisive than the analysis in the moist way. Although it is quite contrary to my intention to enter into this dispute, yet I think myself obliged to state my own private opinion respecting this subject,

independent of the authority of others; which is, that I cannot rank among the products of fire, either the genuine basalt, or its kindred wacke, or the porphyric slate. In this persuasion I am confirmed by personal inspection of basaltic districts, especially of the Bohemian middle mountains; as well as by the habitudes of the above minerals in fire. No. 6—10; 105; 70.

On the contrary, as to what relates to the generation of the obsidian (No. 58, 60), pumice-stone (No. 15), and pretended volcanic zeolite (No. 111), which last is reckoned by some among the pitch-stones, &c. I willingly renounce my own opinion; adding only, that, on considering the arguments for and against their volcanic origin, the circumstance of the obsidian and pumice-stone giving in fire exactly the same products, should not be disregarded; and also, that both these fossils not only accompany each other at Lipari, but likewise frequently occur actually blended.' P. 37.

This essay, as well as the second analysis of black grey flint, is now, we believe, first published. Flint, in this analysis, appears to contain 0.98 of pure silex. The examination of the oriental sapphire, chrysoberyl, chrysolite, lapis lazuli, and olivin, are also new. The experiments on the adamantine spar, the examination of various silver ores, a small blue fossil from Vorau, and the jargon of Ceylon, have been already published.

The hyacinth, as we learn from a newly published essay, contains the circonia as well as the jargon, and is almost wholly composed of it and flint; the former in the proportion of 0.70. It was in the Hungarian red schorl our author found his new metal, the titanium; and the examination is curious, as having led to that discovery. A new fossil, from the district. of Passau, our author would call titanite, as containing also the titanium in a proportion of 0.33. The supposed molybdenous silver of Born our author found to be bismuth,, mineralised by sulphur; and he tells us that the fossil he examined was a fragment of the very individual piece of which Born described the external characters. The native aluminous earth, from Schemnitz, is not of importance: it, as usual, contains a proportion of silex. The cimolite resembles, and has often been considered as, an argillaceous earth; but, like other earths of this kind, it contains a very large proportion of silex. The supposed native muriat of lime, called by Fichter muriacite, exhibits only soda, with the muriatic acid. Its chief contents are gypsum, with a sandy residuum. The native alum, from Miseno, may apparently be made a valuable object of commerce. The native nitre, from Molfetta, appears also likely to be an important production. We shall add a short reflexion, from our author, at present without a comment, but which we shall not lose sight of.

By the computation of Prof. Vairo, the total mass of salt-petre in the pulo should amount to between thirty and forty thousand centners, at 100 lb. each; and the second reproduction of it to more than fifty thousand centners. As, therefore, the alkaline base of prismatic nitre constitutes nearly one half of the whole of that com. pound, it is obvious, that the question which I have intimated at the close of my last essay, concerning the origin of the vast quantity of vegetable alkali, becomes, in the present case, far more important and interesting to the naturalist. The conjecture, that nature possesses means of producing that alkali beyond the limits of the vegetable kingdom, nay, even without any immediate influence of vegetation, acquires, by this singular phenomenon, a very high degree of probability. P. 273.

The mineral waters of Carlsbad are of different temperatures, from 37 to 55 of Réaumur, 16° to 160° of Fahrenheit. They contain soda, united with carbonic, sulphuric, and muriatic acids, in large proportions; with a small proportion of carbonate of lime, and a very inconsiderable one of siliceous earth. Some curious reflexions on the causes of the heat of mineral waters are subjoined. M. Klaproth ridicules the idea of volcanic heat; and thinks that a great part of the heat, at least, is owing to decomposed pyrites, as we have always contended. He adds, however, another cause, which we think unfounded, as there is no supply of air to keep up the inflammation of the coal.

Yet, on a maturer consideration, it will soon be evident, that the dissolved pyrites could not alone afford that quantity of caloric, which has heated the springs at Carlsbad, for several centuries past to this day, with unabated force; but, on the contrary, that, to the production and preservation of natural hot springs in general, another combustible matter is required, from which the subterraneous fire receives its food. And thus it will be obvious, that this fuel can be nothing else but mineral coal, that remainder of vegetablefragments of the ancient world, locked up in the bosom of the earth, which provident nature has wisely reserved.

• When a subterraneous store of mineral coal, such as occurs in various places in strata, of an enormous thickness, has been once set on fire, by ignited pyrites or other causes (as may easily happen, especially where the stratum comes out near to the day) the inflammation will then spread throughout the whole remaining mass, with a quicker or slower progress. A spontaneous extinction and complete refrigeration can certainly not be very soon expected in that case; for the larger the bulk of a burning body is, the longer will the heat, excited by it, continue. If, besides, it is considered, that this immense mass may possibly be inclosed by walls of rocks, impenetrable, and little capable of conducting heat, at the same time that the air finds access to it in but a very small degree; it is then easy to conceive, that ages must pass before the caloric disengaged from such an immense mass can be fixed again, and brought to a, state of equilibrium with the whole.

But that a mine of mineral coal had once been burning at Carlsbad is a fact, unquestionably proved by the earthy scoria that have been erroneously taken for genuine volcanic lavas, by the porcelain-jaspers, and by the other species of stones and earths, more or less changed by fire, covering the fields at Hodorf, Lessa, and other places, in copious quantity, many of which perfectly resemble the pseudo-volcanic products of various countries; such, for instance, as the stratum of mineral coal even now burning at Duttweiler, near Saarbrück.' P. 291.

The comparison of the strontianite and witherite we have had occasion to notice in the Annales de Chymie; and the examinations of the lepidolite, of the magnesian spar (muricalcite), and of the salt springs of Königsborn, with their products, have been formerly published.

The first memoir in the second volume of Klaproth, forming the second part of the translation, is an examination of spinel, formerly confounded with the hyacinths. It is an aluminous earth with silex, containing 0.74 of the former, and 0.15 of the latter.

The emerald of Peru is next noticed, of a similar nature, but exhibiting the largest proportion of silex, viz. o.66, and 0.31 of alumine. The Bohemian garnet, the next subject of inquiry, is nearly of the same kind; but the oxyd of iron is much more copious. In the latter, it is 16.50 in 100 parts; in the former, only 0.50. In the oriental garnet, this metal amounts to 0.36, the silex and alumine to 0.35 and 0.37 re spectively. The Vesuvian gem,-by Werner styled absolutely Vesuvian, the siliceous and calcareous earths are in the chief proportions, viz. in 0.35 and 0.33 respectively, while the alumine amounts only to about 0.22. The proportions differ a little in the Siberian Vesuvian; but the nature is similar.

The leucite is a substance almost peculiar to Italy, perhaps to be traced in no other country, if we except, chiefly from suspicion, Bohemia. It occurs almost wholly in volcanic substances, and was supposed to consist of fint and alumine; yet there was a considerable loss of weight unaccounted for and our author's accuracy was not satisfied by supposing it, as usual, water and air. He traced it with more precision, and found this loss to consist of 0.21 of pot-asha substance supposed to be wholly appropriated to the vegetable kingdom. This will suggest various subjects of consideration. We have already alluded to it, and suspected that it might arise from a percolation of water, previously furnished with vegetable matter. Yet, when we reflect that the proportion is considerable; that it is constant in leucites found at different places; that in those species which have undergone the action of volcanic fires, this proportion is only lessened, we cannot attribute the appearance of the alkali to an accidental impregna

tion. The lepidolite also contains a small but constant proportion of pot-ash.

I now flatter myself with the hope, that, by the experiments here communicated, and several times repeated, I have fully demonstrated the existence of pot-ash in the leucite, as one of its chemical constituent parts. Nevertheless, I am contented to defer the general reception of this new discovery till several other chemical naturalists have re-examined and confirmed it. This trial may be the sooner expected, since my method of proceeding in the main object of this investigation is attended neither with laborious-operations, nor with much loss of time.

But if that alkali, as soon as it can no longer be considered as a substance, produced only in the juices of plants during their vege tation, be required to occupy a more suitable place among the original, simple mineral substances, it will then likewise be necessary to give it a more appropriate name.' p. 366.

We may now add, that the experiments of other chemists have confirmed M. Klaproth's trials; and that our general system of the three kingdoms of nature, as we formerly hinted, is subject to at least one considerable and striking objection.

The pumice-stone has, by every naturalist, been considered as a calcined asbestos. Our author's analysis does not, however, confirm this idea. It contains of flint above 0.77, and of alumine 0.17, with a small proportion of oxyd of iron, and a faint shade of manganese. Perhaps the idea originally arose from its fibrous appearance.

The granular sulphurated barytes, from Peggau, resembles the Carrara marble, but is almost wholly the sulphurated braytes, with a very small proportion, o.10, of silex.

It

The cross-stone (staurolite) is found in the Hartz, and denominated from its double crystals in the form of a cross. consists of nearly one half of silex, with a small proportion of barytes and alumine; but as the experiments since the discovery of strontian were equivocal, our author repeated them. The suspected ingredient appears, however, to be really barytes.

The farther researches respecting witherite and strontian furnish nothing very remarkable; and the analysis of the sulphated strontianite from Pennsylvania is of less importance, since a similar mineral has been discovered near Bristol, and, as our readers may recollect, was the subject of some little controversy between Mr. Clayfield and Dr. Gibbes. This mineral consisted wholly of strontian, earth, and sulphuric acid.

The water of the boiling spring at Rykum in Iceland has been analysed by Dr. Black; and the analysis before us has been already published in the Berlin Memoirs. We should not now have noticed it, but to observe that M. Klaproth claims