Notwithstanding the very considerable extent of shore-line which the deepest-seated rock exposes to the ocean, it exhibits extremely few illustrations of either cliff, or rocky shore.

The rocks which do occur are found to be of an altitude which is altogether trifling,—very much more so than even the great durability of the material of which they are composed would warrant us in expecting. Indeed, from the fact of the shore-line being at right-angles to the strike of the strata, and from these strata being at so high an angle of tilt, we should expect to meet with an almost continuous line of cliff. Instead of this, we find long points of land, of hummocky or undulating contour, running far out into the sea,—a profuse sprinkling of cliffless islets, which resemble in every particular the hummocks of the land,—and long sinuous stretches of water thrusting themselves up into what resemble land-valleys, very much more than sea-bays.

The large series of combinations of copper with sulphuric acid found in mineral veins, present many features which call for attentive study.

Some of the series, as Chalcanthite and Pisanite, are easily soluble in water, while others, as Brochantite and the members of the group allied to it, are insoluble therein, and the solubility seems to run in parallel lines with the percentage of copper.

The “Basic ” sulphates have of late received considerable notice, and English mineralogists must remember with pleasure that the masterly essay by Prof. Maskelyne “On the minerals of the Brochantite group,” gave us for the first time a clear insight into the characters of some of its constituents. This elaborate, paper shewed that the ortho-rhombic varieties were clearly entitled to be divided into distinct mineral species.

Crystals have often been accidentally produced in the various processes of smelting, having the form and composition, or nearly so, of natural minerals; and have been from time to time described in the scientific journals. Some few, however, which have come under my notice have not been, so far as I am aware, previously described; and as the importance to mineralogy of a due regard to the nature of such crystals, as well as the conditions under which they may have been formed, is beyond question, I avail myself of this opportunity to lay before the Mineralogical Society specimens of the few products to which I allude, and to explain the circumstances of their formation:—

Specimen No. 1 contains some dark green crystals of arseniate of copper, resembling in appearance native olivenite. Before the blowpipe on charcoal these crystals melted easily, then, with a sort of deflagration, gave off copious arsenical fumes incrusting the charcoal, and yielded a button of metallic copper.

Every writer has his moods. It may be thought that the present writer was cynical and severe in his remarks on the geognostic features of Caithness. With a view to remove any such impression, Dr. Maculloch's opinion of that country is quoted ; specially in order that it may be used as a foil to what has to be said concerning the geognosy of Sutherland.

Hear then Macculloch. “On entering into Caithness all the pleasures of travelling are gone and past, for an uglier country from one end to the other would not easily be found. In the usual sweeping manner of those who love to generalise, like Humboldt, it is level, or, at least, not hilly, without trees, without enclosures, as black and as flat as Bagshot Heath ; as flat as a pancake ! Nature has provided no monuments, and has refused to be its poet.

I have recently measured one of the crystals of the slag described by by Mr. A. E. Arnold, in vol. III, p. 114 of the Magazine. Observed forms :—

The angles are therefore almost identical with those derived by Miller (Trans. Phil. Soc., Cambridge, III; Brooke and Miller, Mireralogy, 1852, P. 319) from crystals found in refinery cinder, and the slags of copper furnaces, &c, —having the composition of Fayalite, viz.—2 FeO, SiO2.

Chemists have long employed the commoner organic acids, especially acetic, oxalic, tartaric, and citric acids in mineral analysis, but with few exceptions they have overlooked the application of these acids to the decomposition of minerals. Acetic acid has been used to separate minerals from their matrix of calcite ; Karsten (Archiv. of Min. XXII, 572) and Sterry Hunt have used it in the proximate analyses of mixtures of calcite, dolomite, and magnesite; calamine and willemite are sometimes distinguished by the gelatinization of the former with the same acid ; Dr. J. Lawrence Smith (Am. J. Sci., [2] XX, 244) has noticed the solubility of anglesite in ammonium citrate ; W. B. snd R. E. Rogers (Am. J. Sci., 1848) have made experiments on the solubility of minerals in water containing carbonic anhydride ; but there is no record of any systematic investigation of the action of organic acids on minerals with a view to the determination of species.

My notice of this must be considered preliminary in every way. The discovery of “the beautiful carnelian marble of Tyree” has been in a late paper credited to Dr. Walker.

For some years after its discovery, it was used, or attempted to be used for mantle-pieces, and other internal decoration.

Partly on account of the minuteness of its pattern unfitting it for this purpose, and partly on account of the small quantity sent into the market, it, however, seems never to have found its way into general favour.

We find Dr. Macculloch lamenting the wasteful method of working adopted in the quarry,—the wholesale shattering of its mass by the excessive use of “Mines.”

In my former paper (Min. Mag., vol. IV, page 1) the different modes of occurrence of oxide of tin in Cornwall were briefly described, and the characters both macroscopic and microscopic of the ordinary tin-stones and tin-capels were illustrated in considerable detail. I have now to describe the peculiar varieties of “wood-tin” or Cornish tin-ore, which are certainly characteristic of many of the Cornish deposits, although their occurrence is not limited to Cornwall as was at one time supposed.

The chemical composition of Cornish wood-tin differs very little from that of ordinary Cassiterite, as was shown long ago by Klaproth.

Towards the end of the last century one Professor Göttling, who taught chemistry in the schools of Jena, conceived the idea of preparing a portable chest of chemistry, or complete, collection of Chemical Tests. Chemical knowledge being in those days somewhat limited, we are not surprised to find that the contents of the chest could be stowed within a space nine inches square by twelve deep.

This cosmopolitan collection was intended for the use of chemists, physicians, mineralogists, scientific artists, manufacturers, farmers, and the cultivators of natural philosophy. The tests were prepared by a Mr. Hunneman, a friend of the author, and pupil of Klaproth and Hermbstaedt of Berlin; and were put up in thirty five glass bottles and some small wooden boxes.

I give this name to a substance which may be regarded as of the nature of a hydrated magnesian felspar.

It was found by Mr. Dudgeon and myself in granular limestone, about one third of a mile above and north-east of the hamlet of Balvraid; this hamlet is situated six miles up the Glen Beg of Glen Elg, Inverness-shire.

Only a single large mass containing the mineral was found. In this mass it was associated with blue necronite (orthoclase of limestones), Biotite, and a hydrated labradorite.

Its colour is purplish brown of a pale cast; its structure is crystalline granular, it may be called saccharoid; its hardness is 6; its specific gravity from 2·905 to 2·908