The above table is a list of all publications which contain original crystallographic work, observations, or figures relating to Bournonite ; it omits the names of many other works which mention the mineral, but merely contain information compiled from earlier sources; and it refers only to such works as are concerned with the crystalline form. The complete history of the crystallography of Bournonite will therefore be found in the above publications. The most important and comprehensive of these is the monograph of Zirkel published in 1862 ; this paper contains a summary of the previous literature and the results of many new observations, together with a large number of new figures.

At the conclusion of my term of office it is a great pleasure to me to be able to congratulate the Society on the condition of its finances. This, three years since, caused some of us no little anxiety ; now, thanks to the efficient management of our Honorary Secretary, we can look forward to the future with confidence.

Among the minerals found in meteorites, there is none which has attracted the general notice to such a degree as the metallic nickel-iron, especially from the fact that it has hitherto never been seen for certain in any telluric rocks. Nay, so much stress was laid upon this latter circumstance, that such iron was thought never to occur here on earth without having been carried to us from the outer universe, and ever since Chladni's report on the iron-mass of Pallas, every loose block of iron lying on the surface of the ground, nay, even deeply imbedded in it, has generally been declared to be a meteorite, if it only contained a certain percentage of nickel and, which was not always the case, manifested some crystalline texture, called after the discoverer "Widmannstäitten's figures."

It does not appear to be at present a matter of fixed precedent whether the Annual Meeting of the Mineralogical Society should or should not be associated with the delivery of a Presidential Address ; and I had hoped, knowing how slightare my claims to the honour which you have conferred upon me, to have escaped until I give place to a worthier successor. But our Honorary Secretary has intimated to me that he would prefer 'a few remarks' and as I feel so strongly the obligations under which he has placed the Society by the free gift of his valuable time, his will is law to me.

E. D. Clarke was the first mineralogist by whom crystallised graphite was observed and examined. As early as 1821, he described some graphite crystals from the mines at Borrowdale, in Cumberland. Clarke designated graphite by the name of " carburet of iron" or "plumbago," and stated its form to be that of an oblique four sided prism, the obtuse angle of which was found by measurement with the contact goniometer (" the common goniometer ") to be 118°.

I obtained this summer a most beautiful variety of fluor spar, which was raised from the 145 fathom level of the Holmbush Mine. It is of a transparent azure-blue colour, and shows well marked fluorescent phenomena, though not so strongly as that of Weardale, Cumberland.

Some of the specimens are deep blue in one part and limpid like glass in another ; it was found that while the deeply coloured part was strongly fluorescent the limpid part had little or no effect upon the refrangibility of the light passed through it.

When in 1870 Nordenskjöld had made the discovery at Blaafjeld (Ovifak) on the Isle of Disco of the remarkable large iron blocks, there soon, as will be remembered, arose a whole literature on the occurrence and origin of this iron. Although the Danish naturalists had, from the first raised a series of objections against the theory of the meteoric origin of these iron-blocks, the problem of their existence could not be satisfactorily solved without careful geological investigations having been first made into the nature of the whole of the Greenland basalt-formation. Such investigations having been made by Mr. K. J. V. Steenstrup, I was directed by the Danish Commission for the Geological and Geographical Survey of Greenland to make a chemical examination of the materials collected.

In working on the isomorphism of Tourmaline I have been struck by the very peculiar development of a fine crystal from Pierrepont, New York, now in the Cambridge Collection.

The crystal is doubly terminated, of a jet-black colour and splendid lustre. It weighs 814.88 grammes, and measures 1⅙ inch by 1 inch by ½ inch.

The gradual decline in the production of copper from the mines of Cornwall and the consequent diminution of their number renders any discovery of a rare copper mineral an object of interest to all mineralogists.

Owing to the exhaustion of all the upper deposits, those products of decomposition—the beautiful arseniates and phosphates, &c. which adorn the cases of our national collection and those of private collections—are getting more and more scarce, and perhaps in the near future, so far as Cornwall is concerned, we shall have to rely for illustrations entirely on its past productions.

The Periodic Law of the Chemical Elements first foreshadowed by Newlands, and subsequently developed by Mendeleeff and Lothar Meyer, states:—(1) The Properties of the Elements are a Periodic Function of their Atomic Weights. (2) The Properties of the Compounds of the Elements are a Periodic Functiou of the Atomic Weights of their Constituent Elements. This law was explained and illustrated by several examples in the case of both chemical and physical properties, and attention specially directed to the division of the elements, as arranged in Mendeleeff's table (Ann. Chem. Pharm. ; Suppl. 1870-72, p. 151) into odd and even series, and to the somewhat peculiar character of the eighth group of that table. These points were further illustrated by a reference to Lothar Meyer's curve of the elements (Mod. Theor. der Chem.).

Some mouths since I received from J. G. Grenfell, Esq., of Clifton College, a few small specimens of igneous rock which he had collected in the year 1880 on Old Providence Island. This is an island in the Caribbean Sea about 90 miles off the Mosquito Coast, in lat. 13°26'N, long. 81°18 W. Itis oval in shape, 4½ miles long from N to S, and 2¼ miles wide. Barely separated from it on the North is a little island named Sta. Catalina. Bit. Grenfell describes the main island as mountainous, with three chief peaks, the highest of which rises to 1,190 ft. Spurs from these terminate on the shore in peaked hills from 800 to 700 feet high.

The rare occurrence of the primitive rhombohedron r {100} with little or no modification on crystals of calcite has induced me to bring to the notice of the Society some very fine pale lilac crystals exhibiting this unusual habit.

These specimens were raised a few years ago from the Llandeilo flags strata in the Tankerville lead mine, near Shelve, Shropshire.

Garnet is most commonly found in the form of separate crystals embedded in metamorphic rocks; occasionally, but comparatively rarely, in beds or veins. On a recent visit to the Pyrenees, in the Province of Catalonia, I found this mineral forming what appears to be a true dyke. I first noticed an outcrop of it in the steep banks of a brook, in one of the higher valleys of the main mountain chain. At this point it had the appearance of a vein, almost vertical and running nearly East and West ; the wall rock was a highly metamorphic schist, so that its stratigraphical relation to the garnet could not well be made out; however, the general strike of the strata in this district is about East and West.

Every student of crystals is aware how frequently they fall short of the ideal perfection which theory ascribes to them. With regard to the development of the simple forms, the irregularities are most prominent on the crystals which are subject to certain laws of symmetry. In consequence of the differences of size presented on the same crystal by planes belonging to the same form, the most manifold distortions ensue, resulting at one time in the imitation of forms of a lower degree of symmetry, at another in the complete absence of symmetry. Moreover, as long as the faces constituting the distorted form remain the same, i.e. as long as the cause of the distortion is without influence on the development of the combination, so long will the angles of inclination of the circumscribing elements of the individual remain the same, and thus the degree of symmetry can be determined by measurement of the crystal notwithstanding the distortion.

Occurrence. At the Emerald Mines of the Valley of Muso, New Granada, in a gangue composed of anthracitic calcite and pyrites. Lustre, vitreous to resinous ; colour, yellowish brown to honey-yellow. An acute hexagonal pyramid with striations perpendicular to the axis. The crystal measures 84 millim. in length, and 12 millim. in thickness at the base.

The pyramid is perfect and its apex is intact.

All the specimens of Parisite which have been hitherto received, and are found in European Museums, exhibit a truncated hexagonal pyramid. This section is due to a very easy basal cleavage.

Deposits of Diatoms have been long known to exist in Scotland, but such deposits have so far always been of limited extent. Specimens for the microscope have been readily obtained from certain localities, such as Peterhead, but the occurrence of large deposits covering great tracts of land was unknown.

In the year 1881 my attention was directed, by Mr. Hamilton Bell, to a white substance he had obtained from the Peat of Aberdeenshire. During April, 1882, I read a short paper before the Edinburgh Geological Society in which I gave the analysis of a sample received from Mr. Bell, with particulars furnished by the Rev. Geo. Davidson, Minister of Logie Coldstone, Dinner, who also kindly furnished a list of the Diatomaceæ he had identified in the deposit. The list contains some 200 species.

A specimen of crystallised quartz and albite has recently been acquired for the British Museum which has a few isolated crystals of this rare mineral dispersed upon it. Conclusive evidence that the specimen comes from Cornwall is supplied both by the appearance of the quartz and albite and by the presence of the clay-slate with which they are associated.

The mineral monazite or Turnerite has hitherto been discovered in few localities and never in the British Isles. Anatase, however, is mentioned in Greg and Lettsom (Manual of the Mineralogy of Great Britain and Ireland, p. 363) as occurring at Tintagel and near Liskeard in Cornwall ; and it is just possible that crystals of monazite may have been mistaken for anatase.