its earthy base is converted from two to thirty feet deep into a pitchstone-porphyry; sometimes it becomes a pearlstone, at others encloses a true obsidian. These rocks are connected with a silicious trachyte, resembling in appearance the silicious buhrstone of Paris. Resting on the semi-vitreous trachyte and forming the base of the Montagna della Guardia, is a rock 300 feet thick, which the author distinguishes mineralogically from common trachyte, and proposes to call greystone.

In Jannone the trachyte overlies a limestone, which Brocchi describes as transition limestone; at the point of contact this latter becomes dolomite. Having described the whole of this group, the author terminates his paper by connecting their geological structure with that of the neighbouring continent of Italy.

A paper was read, entitled, "Notes accompanying Specimens collected on a Journey through Part of Persia and the Russian Tartaries;" by James B. Fraser, Esq. MGS.

June 4.-A paper was read, entitled, "Description accompanying a Collection of Specimens made on a Journey through the Province of Khorosan in Persia;" by J. B. Fraser, Esq. MGS.

On quitting Teheran, the road passed by the roots of the chain of Elburz, through the pass Gurdunee, Sirdara to Semnoon and Shahrood, over gravelly hills, having to the south a salt desert, and appearances of salt on all sides; thence by Mey Omood, Abbassabad, Muzenoon, and Subzawar to Nishapore, about 40 miles west of which place are found the celebrated torquoise mines, which are worked along the sides and ridges of a narrow valley. The principal mine is called Abdool Rezakee. The calaïte is found pervading a soft yellow stone and a mouldering reddish rock, as also a rock of much firmer texture resembling quartz rock of a grey colour with reddish streaks, and containing specular iron. A conglomerate rock occurs in the vicinity. The mineral is found sometimes in veins, sometimes mammillated in fissures, and at other times irregularly dispersed through the rock. The author describes all the mines actually worked; they are the property of the crown, and were valued, when Mr. Fraser visited them, at the annual rent of 2000 tomauns of Khorosan, or about 35007. sterling, and are farmed to the highest bidder. At Derroad, 25 miles from Nishapore, the primitive rocks of Elburz appeared similar to those seen in the lofty range between Ispahan and Cashan.

A paper was then read, entitled, "Geological Observations on the Sea Cliffs at Hastings, with some Remarks on the Beds immediately below the Chalk;" by T. Webster, Esq. Sec. GS.

This paper commenced with a geographical description of the cliffs on each side of the town of Hastings, from the White Rock on the west to the end of Fairlee cliff on the east, which

form a very instructive natural section of an elevated tract in Sussex, surrounded by, and coming out from under, the clay of the Wealds.

These cliffs consist of alternating beds of sandstone, shale, and clay, more or less charged with oxide of iron, and carbonized vegetable matter. The iron is most abundant in the lower part, where there are beds of two or three inches thick of rich argillaceous iron ore that were profitably worked before the fuel of this part of the country became scarce.

The middle beds of the cliff have much less iron, the greatest part consisting of very white friable sandstone. In the upper part of the series, there are many large blocks of a grey calciferous sandstone, the surfaces of which exhibit a mamillated structure and this rock may be considered as a variety of the chaux carbonatée quartzifère of Haüy, having much analogy with the crystallized sandstone of Fontainebleau. The mamillated appearance is very well seen at the white rock, and has (though erroneously) been usually attributed to the action of the sea upon the fallen blocks.

The fossils, in the cliffs of Hastings, are not numerous; the shells being confined to two or three species of small bivalves, and a univalve resembling that in the Petworth marble. Thin layers of liguite are frequent, and fragments of a very singular silicified wood of the monocotyledon kind, the cavities of which are filled with minute transparent crystals of quartz.

Bones of large Saurian animals, and of birds, also occur, though rarely, together with scales of fish.

The author observed, that the grey calciferous rock has not hitherto been noticed in any part of the formations between the chalk and the Purbeck, except in this district; and from its not being co-extensive with the rest of the ferruginous sand series, and the want of continuity and correspondence in many of the beds, he took occasion to remark, that it may be frequently more correct to consider the subdivisions of some formations rather as irregularly lenticular than as tabular

masses.

June 18.-A paper was read entitled "Notes on Part of the opposite Coasts of the English Channel, from Deal to Brighton, and from Calais to Treport;" by Wm. Henry Fitton, MD. MGS.

This paper was accompanied by a connected series of views or elevations of the coast, drawn by Mr. Webster, from the place where the chalk rises near Calais, to where, after being cut off near Blanc Nez, the chalk again appears upon the shore near Treport; and, on the English side, from the rise of the chalk near Deal, to where it sinks at Brighton. The author expresses his acknowledgments to the Baron Cuvier, through whom he obtained permission from the French authorities to

pass along the coast by sea, and experienced everywhere the greatest attention from the officers of the French customs. The paper briefly describes the leading geological features of the coast, reciting the partial descriptions already published, and referring, for an account of the cliffs near Hastings, to a memoir by Mr. Webster, read at the last meeting of the Geological Society; and for a detail of the beds which form the cliffs from Gris Nez to Equihen, to an account of the lower Boulonnois to be read at a future meeting. From Equihen to the mouth of the Somme, the coast is altogether occupied by dunes of sand, the sand hills being, in some places, especially in the vicinity of Etaples, more than 100 feet in height. These hills are, in general, somewhat crescent shaped, the back of the crescent being turned towards the prevailing wind, and the slope on the lee side much more rapid than the opposite one. The immediate base of the dunes seems to be peat, which is found both on the land side of them, and without, just on the verge of the sea, and in some places, below the level of high water; but no rocks have yet been discovered along the coast beneath the dunes. A list of heights obtained by the barometer is subjoined to this paper, and some detached sketches are annexed to it of interesting geological appearances on the French shore.

ARTICLE XIV.

SCIENTIFIC NOTICES.

CHEMISTRY.

1. On the Nature of the free Acid ejected from the Human Stomach in Dyspepsia.

OUR readers know from the notice of the proceedings of the Royal Society in the Annals of Philosophy (Feb. 1824), that in December last, Dr. Prout read a paper before that learned body, the object of which was to prove, that the acid usually found to exist in the stomach of animals, during the digestive process, is the muriatic. An acquaintance of mine, who occasionally suffers severely from dyspepsia, and was somewhat sceptical as to Dr. Prout's conclusions, lately requested me to examine the fluid ejected from his stomach during a violent dyspeptic paroxysm the day before, with the view of ascertaining the nature of the free acid it contained.

The fluid which had been thrown from the stomach in the morning, fasting, when filtered, was perfectly clear, and nearly colourless; it gave a decided red tint to litmus paper. I distilled about six ounces of it almost to dryness, at a gentle heat, receiving the product in three separate and nearly equal portions.

One-half of each portion was treated with nitrate of silver. The first had no effect on litmus paper, and scarcely gave the slightest cloud with the test. The second became slightly cloudy by the test, but was equally without any action on the blue paper. The third portion reddened the paper strongly, and produced an abundant dense cloud, when I dropped into it the nitrate of silver, and a pretty copious precipitate collected at the bottom of the tube. The remaining half of the third portion was evaporated by a gentle heat to about half a fluid drachm. The precipitate which a drop of it, placed on a slip of glass, occasioned with a drop of nitrate of silver, was insoluble in nitric acid, and perfectly soluble in ammonia. Another drop, similarly treated with muriate of barytes, gave no precipitate, nor cloud. The remainder was neutralized with pure ammonia, further evaporated, and poured on a slip of glass; when it afforded a multitude of well-defined crystals of muriate of ammonia.

The precipitate from the first half of the same portion by nitrate of silver, being collected, washed, and dried, fused on a slip of platina foil before the blowpipe into horn silver.

The presence of free muriatic acid in the ejected fluid, and consequently the accuracy of Dr. Prout's conclusions, seem to be fully confirmed by the preceding experiments.

2. Pyroxylic and Pyroacetic Spirits.

J. G. C.

In a paper read before the Society of Physics and Natural History of Geneva, on the 16th Oct. 1823, MM. Macaire and Marcet have given a description and analysis of two fluids, analogous in many of their properties to alcohol, particularly in being capable, like it, of forming ethers when acted upon by acids. Pyroxylic spirit, the first of these, is obtained during the rectification of pyrolignous acid; the second was described long ago by M. Chenevix under the name of pyroacetic spirit, and may be prepared by subjecting the greater number of the acetates to distillation.

Pyroxylic spirit is colourless and transparent. Its smell is strong, pungent, and ethereal, and has a strong resemblance to that of ants. Its taste is strong, hot, and slightly pungent, leaving a distinct impression of the flavour of oil of peppermint. Its specific gravity, after having been distilled off dry muriate of lime, is 0.828. It boils at 150°. It reddens litmus paper very slightly; but this effect is probably produced by a minute residue of acetic acid; for when the spirit is distilled off litharge, a small portion of the oxide is rendered soluble in water. The dissolved salt is not precipitated by barytes, nor by nitrate of silver, and it contains no nitric acid: it appears, therefore, to be an acetate. When heated, the spirit burns with a fine blue flame, without leaving any residue. Alcohol dissolves it in

every proportion, and the addition of water renders the solution opalescent, and the spirit gradually ascends to the surface. Water alone converts the spirit into a semi-opaque fluid, resembling an emulsion, which persists for an indefinite length of time in this state, without a separation of the two fluids taking place, and without becoming transparent. It is equally insoluble in oil of turpentine. Camphor dissolves in it with great facility. Olive oil does not dissolve in it, either when cold or hot. Potash dissolves in it without producing any sensible alteration, except causing it to assume a yellowish tinge, and producing a slight elevation of tenperature.

Pyroxylic spirit, when mixed with its volume of sulphuric acid, may be distilled over unaltered; but if thrice that quantity of acid be employed, it blackens, and is decomposed, and a small quantity of a gas is evolved, which is a mixture of hydruret of carbon and hydrogen. The gas contains no olefiant gas; for it burns with a feeble blue-coloured flame, and sustains no speedy diminution of volume when mixed with chlorine.

When distilled with its volume of nitric acid, there passes over an ethereal fluid, together with a considerable quantity of nitrous vapours. This new fluid has an agreeable odour, reddens litmus paper even after having been distilled off litharge, burns with a dull heavy flame, and dissolves in all proportions in water and alcohol, communicating to them a sweet taste, like that of sugar. It differs, therefore, in all its properties from

nitric ether.

The spirit is not altered by being exposed to a current of nitrous gas; neither does it yield an ether when repeatedly distilled with its volume of muriatic acid.

A current of chlorine sent through a quantity of the spirit, at first imparts to it a deep-yellow colour; but after the process has gone on for a few minutes, the liquid suddenly becomes again colourless. By this treatment, its volume augments onetwelfth. The new fluid thus obtained is colourless and transparent, and smokes with ammonia. It has a peculiar and very pungent smell, and excites tears. Its taste is hot, leaving an impression exactly similar to that of horse-radish. After distillation off litharge, its specific gravity is 0-889. It burns with a blue flame and a white smoke, which gives thick vapours with ammonia. Water and alcohol dissolve it. It is precipitated by nitrate of silver; and it becomes more acid, and acquires a slight yellowish tinge by exposure for some time to the air and light; but by distillation off a little litharge, it may be restored to its original purity.

These two liquids, formed by the action of nitric acid and chlorine, appear, therefore, to be ethers, endowed with peculiar properties; and the mode in which the pyroxylic spirit is de