"When scratched with a knife, the streak is greyish. "The colour of the powder is a light-green. "Before the blowpipe, it melts readily into a dark-coloured globule. "It displays no electric signs, either naturally or by heat or friction. "It is not magnetic, either in the common way, or by the ingenious method of double magnetism, which we owe to Abbé Haüy. "The acids do not act upon it when cold. When digested a long time with boiling nitro-muriatic acid, about 1-10th is dissolved. The residue is of a lighter colour." The analysis was performed by Mr. Keating, who found it to consist of The following remarks are added by Mr. Keating: "The jeffersonite presents some points of resemblance with the pyroxene of Haüy, but still it can be well distinguished from it. Its cleavages are essentially different from those of the pyroxene, but appear to approach some of the faces of crystais of substances which have been united to this species; for instance, the angles in the diop side (mussite and alalite), fassaite, and in the pyroxene analogique, come very near some of the angles of cleavage obtained in the jeffersonite. I at first indulged the idea that these cleavages might be considered as cleavages parallel to the faces of secondary crystals of pyroxene, but upon reflection I am fully convinced that this is not the case; for the angles which we have measured cannot be deduced from the others by a strict mathematical calculation, and though they may approximate, they are not the same. Besides, no analogy can warrant us in admitting, that the regular cleavages of one substance can disappear entirely, and be replaced by cleavages parallel to secondary crystals. On the contrary, wherever minerals have been found presenting different orders of cleavage, the first or those parallel to the primitive form were always predominant. Thus in carbonate of lime, it is not uncommon to meet the cleavage parallel to the equiaxe, but I believe in every instance the primitive is predominant. In a rarer and more inte resting instance, that of fluor spar, Prof. Mohs has described, and I have seen in his possession in Freyberg, specimens of the Saxon fluor which cleaved in the direction of the cube and the dodecahedron, but the octahedral cleavage was very distinct. Before we change our opinion on this point, we must change all our ideas of cleavage, and of its high importance in the determination of minerals. "In the hardness there is also a remarkable difference, the pyroxene being decidedly harder. The specific gravity is likewise different: the highest specific gravity of pyroxene recorded by Haüy is that of a large crystal from Vesuvius,, which gave 3.3578. The highest specific gravity indicated by Mohs is 3.5, while that of the jeffersonite has, in every instance which I have seen, exceeded this limit. "The chemical analysis offers another important difference, in the absence of magnesia, which appears to be essential to pyroxene. For these and other reasons, I conceive that there can be no doubt as to the necessity of considering this mineral as a distinct species. I am inclined to believe that a closer study of the diopside and fassaite, and of the pyroxene analogique, might lead to their separation from the pyroxene and union with the jeffersonite. This is a subject which appears to me fraught with interest, but upon which I am not able to offer any thing but conjectures, as my specimens of these minerals are not as good as would be necessary to enable me to decide this point. I shall close these remarks merely by observing that a similar opinion is, I believe, entertained by Mr. Vanuxem." IV. Instrument for measuring the Compression of Water. Prof. Oersted has used a very simple instrument for measuring the compression of water. He fills a cylinder of glass with water which has been deprived of its air, the cylinder has on its upper end an airtight cover of brass, through which a screw passes with a small piston of brass on its lower end, which presses on the water. In the cylinder, is a thermometer tube filled with the same water as the cylinder, and having on its upper open end a small column of mercury which, the tube being very narrow, remains there without sinking into the bulb. Suppose now the water being pressed in the cylinder by screwing down the piston, this pressure will act equally powerful on the open end of the tube, as on the outside of the bulb, so that the pressure being equal on the interior and on the exterior side of the glass bulb, neither expansion nor contraction of its walls can take place, the state of the mercury above the water in the glass tube will, therefore, immediately indicate the compression. Professor Oersted had previously ascertained the capacity of the bulb and of the tube by weighing the mercury which they were able to hold. The pressure exerted by the screw on the water was measured by another tube filled with air, likewise inclosed in the cylinder. Thus he obtained the result, that the compressibility of water diminishes very quickly with the increase of pressure, and that the mean compressibility at a pressure of 3 to 4 atmospheres is 45.0 for each atmosphere, which agrees pretty well with the experi 1000000 ments of Canton. V. Tutenag. This substance has lately been analyzed by Dr. Fyfe. The following is the Doctor's account of the specimen he examined: "Dr. Howison, of Lanarkshire, was so fortunate, when in China, as to procure a basin and ewer of Chinese or white copper, a part of which he sent me for analysis. From the experiments I have performed on it, I find the composition to be different from what is stated by the above-named chemists, its component parts being copper, zinc, nickel, and iron; the last of which, however, is but in small quantity. "The basin in the possession of Dr. Howison is of a whitish colour, approaching to that of silver, and is very sonorous. When held in one hand, and struck with the fingers of the other, the sound is distinctly heard at the distance of an English mile. It is also highly polished, and does not seem to be easily tarnished. The piece that was sent me I found was malleable at a natural temperature, and at a red heat; but when heated to whiteness, it was quite brittle, breaking with the slightest blow of a hammer. By great caution, it was rolled into thin plates, and was drawn into wire, of about the thickness of a fine needle. When fused in contact with the atmospheric air, it oxidated, and burned with a whitish flame, in the same way as zinc does. Its specific gravity at 50° was 8.432. "Five grains of it were subjected to analysis, with the view of ascertaining the proportion of its ingredients; the result was, "The method which is practised in preparing white copper is not known in this country, though it seems to be the general opinion that it is procured by the reduction of an ore, containing the ingredients of which it is composed. In a letter I received from Dr. Howison, he mentions, that Dr. Dinwiddie, who accompanied Lord Macartney to China, showed him, when at Calcutta, several specimens of the ore from which he was told the white copper was procured, and which he obtained at Pekin. The basin, in the possession of Dr. Howison, cost in China about one-fourth of its weight in silver; and the exportation of utensils of this alloy is prohibited. These circumstances also render probable the opinion, that the white copper is obtained by the reduction of a metallic ore, for in China, labour is cheap, and the metals composing it are said to be found in great abundance.-(Edin. Phil. Jour.) ARTICLE XI. NEW SCIENTIFIC BOOKS PREPARING FOR PUBLICATION. Mr. P. W. Watson, of Hull, is preparing a work, to be entitled "Dendrologia Britannica: containing an Account of the Trees and Shrubs that will live in the open Air of Britain the whole Year;" and to be illustrated with coloured Plates from living Plants. Mr. Worsdale, sen. of Lincoln, has ready for the press," Celestial Philosophy, or Genethliacal Astronomy," containing the whole Art of calculating Nativities, and a great number of Genitures. To be published in 25 Numbers, 8vo. Mr. Wood is preparing a complete Illustration of his Index Testaceologicus, in which he will give an accurate Figure of every Shell. Mr. T. Coar has in the press, the Aphorisms of Hippocrates, with Translations into Latin and English. Anatomical and Physiological Commentaries, by Herbert Mayo, Surgeon, and Lecturer on Anatomy. 8vo. To be published in Numbers. JUST PUBLISHED. Observations (from Experience) on the Aid obtained in various Diseases, particularly those incidental to Tropical Climates, by the External Application of Nitromuriatic Acid in a Bath. With several Cases, wherein it has been used by the Author with great Utility. To which is added the present most approved Mode of mixing the Acids and preparing the Bath. By Phineas Coyne, MRCS. London, &c. 8s. 6d. Boards. An Introduction to the Study of Fossil Organic Remains, especially of those found in the British Strata; intended to aid the Student in his Inquiries respecting the Nature of Fossils, and their Connexion with the Formation of the Earth. By James Parkinson, FRCS. MGS. WSE. and Cæsarean Society, Moscow. With Plates. Post octavo. 12s. Geological Essays; comprising a View of the Order of the Strata, the Coal Fields and Minerals, of the District of the River Avon; an Introduction concerning Primitive, and the Flood-washed Earth; Refutation of Errors, and Notes from the Best Authors. By Joseph Sutcliffe, AM. Author of a Grammar of the English Language. 8vo. 4s. The Study of Medicine: comprising its Physiology, Pathology, and Practice. By John Mason Good, MD. FRS. Member of the Royal College of Physicians, London, &c. 4 large Vols. 8vo. 31.4s. ARTICLE XII. NEW PATENTS. D. Gardner, Edmund-place, Aldersgate-street, for a stay, particularly applicable to supporting the body under spinal weakness, and correcting deformity of shape.-June 18. J. Wass, Ashover, Derbyshire, millwright, for an improvement, which prevents the ill effects to vegetation and animal life that has hitherto been occasioned by noxious fumes and particles that arise from smelting or calcining lead ore, &c.-June 15. M. I. Brunel, Chelsea, engineer, for improvements on steam-engines. -June 26. T. Gauntlett, Bath, surgeons'-instrument-maker; for improvements on vapour-baths, by which the heat is better regulated, and the baths rendered more portable.-June 26. W. Brunton, Birmingham, engineer, for improvements upon firegrates, and the means of introducing coal thereon.-June 26. L. B. Rabant, Skinner-street, Snow-hill, Gent. for an improved apparatus for the preparation of coffee or tea.-June 26. T. Postans, Charles-street, St. James's, Gent. and W. Jeakes, Great Russell-street, Bloomsbury, ironmonger, for an improvement on cooking apparatus.-June 26. G. Smart, Pedlar's Acre, Lambeth, civil engineer, for an improvement in the manufacture of chains, which he denominates mathematical chains.-July 14. J. Smith, Sheffield, book-keeper, for an improvement of, or in, the steam-engine boiler.-July 4. |