of the Geological Transactions, and the author thinks it probable that it may rest on greenstone analogous to that of those two situations. The shell limestone also of Bromsgrove Lickie being identical with that which occupies a still higher portion in both those ridges.

Between Cradly and Stourbridge in the north-east angle of Worcestershire, fragments of the quartz rock rounded by attrition are found in a gravel pit imbedded in what seems to be a decomposing trap, probably identical with the slaty micaceous greenstone of the Wrekin. Portions of the trap fall off from the sides of the pit in flakes; but it is remarkable that the planes of separation pass without interruption through the pebbles of quartz rock and the trap; so that the sides consist of smooth vertical surfaces, like those which are said to occur in the cliffs of the pudding stone at Callender.

ARTICLE XVII.

SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS CONNECTED WITH SCIENCE.

I. Analysis of an Iron-ore from Brazil.

Baron d'Eschwege, director-general of the mines of Brazil, has sent to M. Vauquelin for analysis a specimen of an iron-ore, which is found in detached pieces with micaceous iron-ore and topazes, in decomposed chlorite-islate, at Capao, near Villa Rica. The colour of this mineral is black; its fracture has a very strong lustre, resplendent as a mirror. When bruised, it is reduced into little micaceous laminæ ; its powder is brown, and it is slightly attracted by the magnet. Sp. gr. 5.260, In muriatic acid it dissolves entirely, but is insoluble in nitric acid; exposed to a red heat, it augments a little in weight.

Dissolved in muriatic acid, it precipitates gold from its solution in the metallic state, proving that it contains protoxide of iron; but as a large quantity of the ore is requisite to precipitate a small quantity of gold, it cannot contain much of that compound. M. Vauquelin concludes, from an experiment in which 200 parts, calcined in a platinum crucible, augmented in weight 3 per cent., that this iron ore consists of

besides a small quantity of phosphoric acid and of manganese. It is probable, he observes, that all the iron-ores slightly attractable by the magnet, are similarly constituted.-( Ann. de Chim, &c. xx. p. 85.)

II. Geology of the Sierra Nevada of Grenada.

This chain of mountains, more elevated than the Pyrenees, and crowned, on some points, with eternal snows, has been geognostically

examined by Don Josef Rodriguez, director of the Observatory of Madrid, and one of the most eminent disciples of the school of Freyberg. According to the geometric levelling of Don Clemente Rojas, the Picacho de Veleta is elevated 3,447 metres, or 11,309 feet above the sea and the altitude of the Cerro de Mulhacen is 3,531 metres, or 11,585 feet.

The formations which constitute the entire mass of these mountains are primitive, and have great uniformity. They are mica-slates, which pass into gneiss and clay-state (phyllade, thonschiefer); and which contain subordinate beds of eupholite (serpentine, diallage rock), of quartz, and probably also of greenstone (diabase). There is neither granite nor true gneiss; nor are the fragments of those rocks found even in the neighbouring alluvial tracts. The existence of greenstone in subordinate beds is rendered extremely probable by the blocks of that substance which are dispersed around the principal chain. In this greenstone crystallized garnets are disseminated, as in that of the mica-slates collected by Humboldt in the chain of the littoral of Caracas. On the southern declivity of the Sierra Nevada, clay-slate reposes on the mica-state, and supports, in its turn, black transition limestones rich in sulphuret of lead.

It might appear from the abundance of the beds of greenstone, that the whole mass of these mountains belongs to the transition formation; but it must not be forgotten that the stanniferous granites of the Fichtelgebirge in Franconia also present beds and veins of greenstone, and that M. de Buch has discovered primitive eupholites in the North of Europe. The strata of rocks which compose the Sierra Nevada are inclined in the form of tiles; that is to say, their direction is nearly parallel to that of the central chain, and they dip towards the north on the northern declivity, and towards the south on the southern. In the Alps, the strata are most frequently inclined towards the centre of the chain; on the coast of Italy they dip to the north. It will be interesting to the geognost to be well acquainted with the relation of the volcanic rocks of Cap de Gates to the intermediary and primitive formations of the Sierra Nevada. The tract which surrounds this chain is so elevated, that the upper platform of the tower of the Cathedral of Grenada is itself 784 metres, or 2,572 feet, above the marine level.→ (Ann. de Chim. &c. xx. p. 99.)

III. On the Preparation of Formic Acid from Tartaric Acid. Professor Dobereiner has found that when bitartrate of potash, or pure tartaric acid, is slightly heated with black oxide of manganese and water, a great quantity of carbonic acid escapes, and a sour colourless liquid distils, which is formic acid.

1. It is, even at the common temperature of the atmosphere, decomposed by concentrated sulphuric acid into oxide of carbon and water. 2. By nitrate of silver and pernitrate of mercury, when slightly heated, it is completely converted into carbonic acid, while the oxides are reduced to a metallic state.

It may be added, that diallage-rock and serpentine occur associated with gneiss, mica-slate, and other primitive rocks, in the Shetland Isles; and that the latter is also found in detached beds and masses in the granite of Aberdeenshire. There does not, indeed, appear to be any reason for supposing that the rocks of the Sierra above noticed belong to the transition class.-Ed.

3. It forms with barytes, oxide of lead, and oxide of copper, salts which have all the properties of formates.

What remains after the distillation in the retort, is, when tartaric acid has been used, tartrate and formate of manganese. If sulphuric acid be added, together with the black oxide of manganese, all the tartaric acid is decomposed into carbonic acid, water, and formic acid, and a greater quantity of the latter is obtained than in the former experiment. The best proportions for obtaining this acid are 78 parts of crystallized tartaric acid, 105 of black oxide of manganese, 115 of sulphuric acid, mixed with 2 or 3 parts of water.

Professor Dobereiner believes, that when nitric acid acts upon sugar, alcohol and formic acid are formed, and he finds that the easiest method of ascertaining its nature is to try the effect which sulphuric acid, and nitrate of silver, or pernitrate of mercury, have on the acid, either combined with water or with bases.

IV. Bezoars voided by a Woman.

The calculi called bezoars are found in the stomach and intestines of certain herbivorous animals, but had not been met with in those either of carnivorous animals or of man, until Dr. Champion, an eminent physician of Bar-le-duc, sent some for analysis to M. Henri Braconnot, which had frequently been voided, in a diurnal vomiting of blood, by an unmarried woman, whose menstruation was irregular, and whose urine had become much diminished in quantity before the evacuation of these concretions commenced.

These bezoars have the form of crisp almonds (pralines) and are as large as small hazel nuts; their surface is tubercular and coloured brownish red by the blood. Internally they are of a yellowish white, inclining to fallow, and appear to consist of brilliant crystalline grains; they do not present any concentric layers. They are usually of a close texture, but are sometimes cellular, like the marrow of bones; and may be cut with a knife like wood, of which they have also the aspect. At one of their extremities there is an infundibuliform depression, often filled with dried blood, which communicates with a tube extending throughout their length; this tube being sometimes partially or even wholly filled up. Two of them had cavities in the interior, like little geodes, but none offered a distinct nucleus; their specific gravity was above that of water.

These bezoars being boiled in water and the liquor evaporated, a slight residue was obtained, containing a free acid, the muriates of soda and potash, and a small quantity of animal matter. They were then treated with a solution of potash, which had little action upon them; a brown fluid resulted, however, in which muriatic acid occasioned a slight precipitate, that did not contain any uric acid. Every thing having thus been obtained from them that these solvents could extract, they were triturated with concentrated sulphuric acid, with which they produced a thick mucilage, that by solution in water and ebullition for some hours, was converted into sugar.

They were not acted upon by muriatic acid; by treatment with nitric acid 2 grammes of them yielded 0-4 grammes of oxalic acid, a small quantity of yellow bitter matter (amer), and an insoluble white substance resembling baked starch; this is readily soluble in am

monia, from which it is precipitated by acids in the form of a colourless jelly.

These bezoars are inflammable, but do not emit while burning the fetid smell which characterizes animal matter in combustion. Four grammes distilled in a glass retort, yielded 0.5 of a brown empyreumatic oil, and 1.7 of a yellowish fluid, which strongly reddened turnsol paper, and also contained ammonia. There remained in the retort 1.1 of charcoal, which left after combustion 0:14 of grey ash, affording to water the muriates of soda and potash, with traces of a sulphate and carbonate; and to muriatic acid some phosphate of lime; 0.02 grammes of silex remaining undissolved.

"It results from the preceding facts," says M. Braconnot," that the bezoars vomited by the woman of Bar-le-duc have absolutely all the properties of wood; they bear a great resemblance to those which were found among the presents sent to France by the king of Persia, and which have been examined by M. Berthollet. But it is to be remarked that these oriental bezoars were easily soluble in potash, whilst ours are dissolved only in very small quantity by it. This would appear to render their resemblance to wood still more perfect." (Ann. de Chim. &c. xx. p. 194.)

V. Fall of a Meteorite at Angers.

The following particulars respecting this event are derived from a letter of M. Desvaux, keeper of the Museum of Natural History at Angers.

At a quarter after eight in the evening of the 3rd of June, in the present year, the sky being cloudless and the air calm, there was seen at many places, such as Loudun and Angers, towns sixteen leagues distant from each other, a vivid meteor to the south-east of the latter place, which remained visible for many seconds. To this succeeded a very loud detonation, followed by a rapid succession of reports of less intensity, resembling a running fire of musketry, and continuing for five or six seconds. This fire-ball, much nearer to Angers than to Saumur, appears to have had its centre of action over St. Jean-desMauvrets, a league and a half from Angers, on the left bank of the Loire. Luminous traces appeared in the atmosphere after the detonations, and a shower of stones descended, of which one, weighing 30 ounces, fell into a garden at Angers; the ground being hard, it made only a very slight hole, and being taken up at the moment of its fall had no particular heat; the temperature of the atmosphere was betweeen 81° and 82° Fahr.

This meteorite, which appears to have been the only one of the shower that had been taken up, is described as being an irregular angular fragment, evidently a portion of a larger mass, invested with a brown black crust, on part of which is a bubble; and presenting, interiorly, the same aspect and structure as the stones which fell at l'Aigle in 1802.

An interesting account of the meteor itself is given in a letter addressed to M. Arago by M. Boisgiraud, sen. Professor of the Physical Sciences at the Royal College of Poitiers; of this the following is an abstract:

There was seen at Poitiers, at eight o'clock, in the evening of the 3rd of June, a beautiful falling star in the NNE, consequently near the

magnetic meridian; it resembled in its brilliancy and in the nature of its light, the fire-work called a Roman candle. It left after it a luminous rectilinear train, which, attenuating towards the top, increased in diameter as far as a point a little above its lower extremity. This point, more luminous and of greater diameter than the rest, also remained for a much longer time; it subtended an angle sufficiently sensible. The inferior extremity of this train was in the constellation Auriga, passing between the stars Capella and ; by degrees it altered in form, and presented, nearly, the aspect of the projection of a helix traced upon a cylinder. The extent of this helix diminished in proportion as its diameter augmented, and its brilliancy sensibly decreased at the same time. After some minutes its continuity ceased, and it became divided into two branches, the superior of which contained the greater portion of the curve, and both extremities of each branch were directed towards the west. The upper branch continued slowly to diminish in brilliancy, and without change of place or further alteration of form it ceased to be visible in ten or twelve minutes after its first appearance. The inferior branch still presented an irregular curve, and after the lapse of some minutes, nothing of it remained except the brightest point, or nucleus, the lustre of which became slowly extinguished. The position of this nucleus with respect to the two stars above mentioned, as far as could be judged without an instrument, appeared to be invariable; notwithstanding that the phenomenon continued for a quarter of an hour, and that the diurnal motion of the stars had been sufficiently sensible. (Ann. de Chim. &c. xx. p.89.)

VI. Case of a Man swallowing Clasp Knives.

Dr. Marcet has given a curious and detailed account of this case in the 12th vol. of the Medico-Chirurgical Transactions, from which we extract the following particulars:

In the month of June, 1799, John Cummings, an American sailor, about twenty-three years of age, being with his ship on the coast of France, and having gone on shore with some of his ship-mates, about two miles from the town of Havre de Grace, he and his party directed their course towards a tent, which they saw in a field, with a crowd of people round it. Being told that a play was acting there, they entered, and found in the tent a mountebank, who was entertaining the audience by pretending to swallow clasp-knives. Having returned on board, and one of the party having related to the ship's company the story of the knives, Cummings, after drinking freely, boasted that he could swallow knives as well as the Frenchman. He was taken on his word and challenged to do it. Thus pressed, and though (as he candidly acknowledged in his narrative) "not particularly anxious to take the job in hand, he did not like to go against his word, and having a good supply of grog inwardly," he took his own pocket-knife, and on trying to swallow it "it slipped down his throat with great ease, and by the assistance of some drink and the weight of the knife," it was conveyed into his stomach. The spectators, however, were not satisfied with one experiment, and asked the operator "whether he could swallow more ?" his answer was, "all the knives on board the ship;" upon which, three knives were immediately produced, which were swallowed in the same way as the former; and, "by this bold attempt of a drunken man," (to use his own expressions) "the company