may be simply dependent on the rapid cooling, or any other cause which gives the iron its brittle character. Another patch of etching was made near the narrow extremity of the pointed portion of the mass (fig. 2). Here the crystalline structure of crossing lines is less distinct, the metal being apparently more granular in its texture, and exhibiting a series of shining points. The action of the diluted acid on the metal was closely watched, and was stopped occasionally, so as to preserve the appearance of the etching, when its character was most distinct. Wax squeezes and electrotype casts were taken from these etched surfaces, and are here printed from as woodcuts (figs. 1, 2). They may therefore be compared with that figured before, which was taken in a similar way from the central part of the meteoric iron. A portion of this meteoric iron, with plaster cast of the entire mass, are now preserved in the Natural History Museum, Edinburgh; the principal part of the iron is in the British Museum, London.] Analysis of the Meteorolite described in the foregoing paper by Dr John Alexander Smith. By MURRAY THOMSON, M.D., F.C.S., Lecturer on Chemistry. In giving a chemical description of this remarkable mass of meteoric iron, I have to call attention, in the first place, to its Specific Gravity; the process of taking which was first performed on the undivided meteorite, and afterwards on each of its halves. Of course, with such a weighty mass this process could not be done by means of the ordinary delicate balance. I had therefore recourse to the standard beams and weights contained in the office of the Inspector of Weights and Measures at the County Hall, Edinburgh. The weight in air of the whole mass was 32 lbs., 11 oz., 11⁄2 drs., avoirdupois, equal to 39.60 lbs. Troy weight. The weight in distilled water was 27 lbs., 10 oz., 13 drs. This gives a specific gravity, it will be seen, of 6.517, which is very low for meteoric iron. It stands at the lowest limit of recorded specific gravities of other meteoric irons. Shepard (Silliman's American Journal of Science, vol. ii. New Series, p. 377) gives the specific gravities of iron and nickel meteorolites as ranging from 65 to 8.00. After the mass had been divided, the specific gravity was taken in a similar manner to the above, and the larger, heavier, and more solid half, gave a specific gravity of 6-499; the smaller and lighter half, as already mentioned by Dr Smith, having been broken in two, the process of taking the specific gravity was repeated on each of these, with the following results : The smaller, rounded, or lobed portion gave, 6·1919 The higher specific gravity of the pointed portion is apparently accounted for by its having been compressed more than the other parts. Dr Smith has also noticed that this portion was stated to be tougher before the edge of the graver. The analysis was made on some filings of the mass obtained before polishing the surfaces of the halves. I should have preferred for this purpose a sample derived from various parts of the mass, but this, it would appear, was not easy to obtain without endangering the good appearance of the meteorolite. There is no point in the analysis calling for special description, except, perhaps, the determination of the nickel. This metal was estimated by dissolving a known weight of the meteorolite in hydrochloric acid, and after separation of the gangue of carbon and silica, the iron was peroxodized by heating with nitric acid, and then the iron oxide was precipitated by carbonate of baryta, and the excess of baryta afterwards removed by sulphuric acid. The precipitate of sulphate of baryta was separated by filtration, and the filtrate presented a decided green colour, which on concentration was deepened, showing the amount of nickel it contained to be considerable. The nickel in this solution was then precipitated and weighed as oxide. To arrive at a good result, it was necessary to operate on as much as 60 or 70 grains of the meteorolite. In the course of this process other metals, such as manganese, chromium, cobalt, as well as magnetic oxide of iron, &c., were carefully sought for, but no trace of them could be discovered. The qualitative analysis, therefore, showed the presence of VOL. II. 3 H iron, nickel, carbon, and silica; and these are present in the It will be seen, therefore, that its composition is very simple, but at the same time not unlike that recorded in the analyses of other masses of meteoric iron. The occurrence of nickel in it, in such marked quantity, sets at rest any question that might be raised as to its meteoric origin. Though one or two pieces of undoubted meteoric iron exist without any nickel in their composition, yet that metal is held by Shepard (vide Silliman's Journal, ut sup.) to be the second most frequently occurring constituent. [After the above communication was written, and as a portion of the mass had been cut into pieces of various sizes, another opportunity was had of taking the specific gravity of a slice (separated into two portions), embracing the whole thickness of the mass. These pieces being more manageable for the purpose of taking density, it is to be presumed that the following numbers express, with the utmost accuracy, their specific gravity:— Slice from the pyramidal or pointed portion gave, 6·750 sp. gr. It was also noticed, in examining a small portion of the first of these slices, where the metal was corroded-looking, and showed various black spots on its surface, that this iron was very brittle; so much so, that no difficulty was experienced in reducing a fragment of it to powder in an iron mortar. I would likewise here record, that a further chemical examination was made, chiefly in search of magnetic oxide of iron, which is so frequently a constituent of meteorites, but, as before, I could obtain no evidence of the existence of this substance. It has been already stated that the portion of the meteorite used for analysis was that obtained by filing the exposed faces of its halves; it might therefore be objected, that the material so procured, at least from the harder portion, was likely to be mixed with particles of the file used, and especially that the percentage of the carbon in the meteorite might thereby come out too high. It certainly cannot be denied that minute particles of the substance of the file would mix with the filings; but from the texture of the mass these must have been but a very trifling proportion, compared to the bulk of the filings. To be certain, however, that no substantial error had crept in from this source, another determination of the carbon and silica was made on a solid piece of the meteorite, the result being to show the presence of these constituents in the following proportions : These new percentages being so close to the last, we may regard the first analysis as quite correct.] III. On Professor M'Coy's Ray without a name, taken in the Firth of Forth, May 1861. By WILLIAM S. YOUNG, Esq (The Specimen was exhibited.) After carefully examining several authorities, I have come to the conclusion, that this ray is the same as one described, but not named, by Professor M'Coy, in the "Annals of Natural History," vol. vi. p. 405, and which Yarrell, quoting Thomson, places under the species of Sandy or Cuckoo Ray. Couch, in his work on the "History of the Fishes of the British Islands," now coming through the press, arranges them as two distinct species, and neither description coincides with the specimen now before us. The specimen M'Coy got in Dublin bay was considerably larger than this one, being 17 to 18 inches long, and 9 to 10 inches broad. He says its outline,-the semicircle of spines or inner margin of the eye, and the spines at the tip of the snout, are the same as in the Sandy Ray; and that it resembles the Sand or Homelyn Ray, in having one spot on each pectoral, that is, a circular spot of chocolate brown, surrounded by a circle of white irregular spots, and some irregular white markings in centre, instead of the numerous small white markings of the Sandy Ray. It differs from the Sandy Ray, in having the surface of the body covered with minute spines, directed backwards,-the Sandy Ray being smooth, although Yarrell describes it as covered with spines. This specimen also differs from the Sandy Ray in its tail being long, whereas in the latter it is remarkably short; and, having the characteristic outline and disposition of the spines of the Sandy Ray, easily distinguishes it from the Sand or Homelyn Ray. M'Coy thus gives the description of his fish, which so closely agrees with this specimen, that except in one or two minor particulars they appear to be the same species: Spiracles immediately behind the orbits. Skin rough above, with the spines largest on the anterior margin of the pectorals. Semicircle of six or eight spines round the inner margin of the orbits, and a few on the top of the snout; four short rows about or a little before the middle of the back (these, I think, are the transverse rows forming the triangle at the upper extremity of the rows of large spines); two rows equally large spines down each side of the tail; four rows of large spines on the tail pointed backwards; central line comparatively unarmed; all the larger spines radiated at their base. Pectorals more abruptly rounded off than in the Sandy Ray. Colour uniform, light yellowish brown, the large oval spot containing variously shaped cream-coloured spots." Such is Professor M'Coy's description of this ray without a name. The following is the description of the specimen now exhibited length 12 inches, breadth 63 inches; from the vent to the tip of the snout, 5 inches; from the same point to the tip of the tail, 7 inches (these proportions are very much. the same as in M'Coy's ray); eyes large; spiracles immediately behind the orbits; skin rough above, thickly covered with spines, which are larger on the anterior margin of the pectorals, and all of which, even to the most minute, are radiated at the base. At the upper end of the central line is |