This communication chiefly described the observations made by W. S. Jacob, Esq., of the Madras Observatory, during the last apparition of the planet, with a telescope having a six-inch object-glass, lately completed by Lerebours and Secretan.

Previous to its being sent to India, the object-glass had been tested at the Edinburgh Observatory; and its quality, which was then approved, had been more conspicuously brought out in the subsequent trial in a clearer climate.

Immediately after the receipt of the object-glass, in September 1852, Mr Jacob directed it to Saturn, then in the zenith, and immediately perceived the “transparency” of the dark ring which has since been discovered independently by Mr Lassel and others; and on very accurately adjusting the focus, he saw a fine division in the outer dark ring.

1. On the new compounds of Cobalt described by Frémy and others.

Claudet in London, and Genth in Germany, about the same time observed a new compound of cobalt, with the elements of ammonia and chlorine. Frémy, about the same time, announced a far more extended investigation, the result of which was the discovery of no less than five series of salts, in some of which the base, with oxygen acids, was formed of oxides of cobalt along with more or less ammonia, and, with hydrogen acids, was formed of cobalt with more or less ammonia. In other series, salts of oxides of cobalt, for the most part previously unknown oxides of this metal, seem to have combined with more or less ammonia.

In proceeding to consider still farther the physiology of rocks, the author proposed in this communication to confine himself to the illustration of

1. The Columnar Structure.—After enumerating examples of this structure, as occurring in the neighbourhood of Edinburgh, in cannel coal, sandstone, clay, ironstone, clinkstone, claystone, greenstone, and basalt, he exhibited examples of similar appearances in oven soles and fragments of the walls of vitrified forts. The ordinary explanation of this structure as the result of cooling from a state of fusion he pointed out as unsatisfactory, even in the case of basaltic pillars, and inapplicable to similar appearances as occurring in sedimentary rocks.

In this communication the attention of the author is chiefly directed to two subjects of inquiry:—

1st, The comparative nutritive power of fish, taking the specific gravity of their substance, and the proportion of solid matter left on thorough drying, as a measure of the same. In illustration, two tables are given, containing the results of trials on several kinds of fish and other articles of animal food; from which he deduces that the difference of nutritive power of these several articles, has commonly been overrated.

The Torbanehill mineral is so very peculiar that I cannot call it either a bituminous shale or a coal, to both of which it has a considerable resemblance.

After comparing it carefully with a great variety of English and Scottish coals, and with many varieties of bituminous shale, I conclude that it is a mineral hitherto undescribed by systematic mineralogists, and propose for it the name of BITUMENITE.

It appears to me to have been formed by the impregnation or injection of shale with liquid bitumen. Its colour is blackish-brown. Its specific gravity = 1·284.

The author commenced with a general sketch of the natural character and condition of the great cave, as it is the peculiarities of their local position which constitute the most remarkable feature in the history of the animals by which it is inhabited. The cave descends through the uppermost rocks of the “Barrens” to those which are nearly or quite upon a level with the Ohio. Though called a cave, it is in fact a series of underground galleries, branching from and inosculating with each other in various directions, the total length of windings being almost incalculable, and even the direct distance from the entrance to the termination extending many miles.

The author, after mentioning his previous communications on this subject, stated, that continued investigations of the deposit had yielded the extraordinary number of about 150 species of Diatomaceæ, and that as several of these had been only recently observed, it was nearly certain that more yet remained.

Of these species, from 12 to 15 appear to be undescribed, and there are also 7 or 8 new to Britain, or not hitherto admitted as British species.

Referring to the general descriptions which had been published in scientific journals and elsewhere of the appearance of this comet, the author pointed out,—1st, That the colour which had been attributed to it was merely the adventitious tint due to the twilight atmosphere through which it was seen. 2dly, That what had been described as the nucleus of the comet, and of so many thousand miles in diameter, nine days before the perihelion passage, was merely the head, composed of the same light, vaporous transparent matter as the tail; and subject to the same remarkable compression and conden-sation on approaching the sun.

The discussions which arose about four years ago on the animal reported to have been seen on 6th August 1848, by Captain M'Quhae, the officers and crew of H.M.S. Dædalus, in the Southern Atlantic, between the Cape of Good Hope and St Helena, about 300 miles off the African shore, recalled my attention to the materials I had collected respecting the vast animal cast ashore on Stronsey, one of the Orkneys, in 1808.

I was not there at the time, but copies of the depositions made by those who had seen and measured it were transmitted to me by order of Malcolm Laing, Esq., the historian of Scotland, on whose property it was stranded; and I obtained other notes from several individuals resident in Orkney.

Dr Fleming, after stating the circumstances which led him to bring before the Royal Society the consideration of this question, pointed out the distinction between a mineral species and a rock, a circumstance which had been greatly overlooked in recent discussions on the subject. He considered coal as a rock, and capable of being traced, in its origin and history, from peat at the beginning of the series, to blind coal or anthracite at the termination.

He illustrated the character of peat in reference to the vegetables from which it was derived—the changes of a mineralizing nature which it had undergone—and the strata of sand, clay, and marl with which it is usually associated.

The author stated that the coal to which he called attention was found at Fordel collieries, near Inverkeithing, Fife, and that he was indebted for specimens of it to Mr Robert Daw, comptroller of customs at Leith. It is a splint coal, and exhibits numerous vegetable impressions, particularly of Sigillaria and Stigmaria. These plants appear, indeed, the author thought, to have formed the main substance of the coal, as shown not only by its external appearance, but also by its microscopical structure. Cellular and woody tissue have long been recognised in coal; but from what is now seen in the Fordel and other varieties, it would appear that scalariform and dotted tissue are often present, and, moreover, that in some instances peculiar dotted vessels have been mistaken for true punctated woody tissue.

The author has been induced, he states, to make inquiry on this subject, in consequence of a recent averment, founded on a reported experiment, that the ova of the trout taken from the abdomen of the parent fish, and not afterwards mixed with the milt, have proved prolific.

He first gives an account of many trials made to test the accuracy of the conclusion that the ova of the Salmonidæ may be impregnated ab externo, the results of all which have been negative, and remarkably contrasted with those in which, after exclusion, the milt and roe have been mixed,—impregnation having been effected and the eggs rendered prolific.

On the 30th September 1853, I was with my friend Mr David Wallace, in a field near his house, Balgrummo, in the neighbourhood of Leven, in Fifeshire. The atmosphere was very clear, and the sun was shining brightly. The sky was covered in some quarters with thin cirrous clouds, and we had been watching the changes in the appearance of the clouds nearly overhead, when Mr Wallace, who was still observing the sky, pointed suddenly upwards, and called on me to look. I did so, and instantly saw a round body, apparently as large as a star of the first magnitude, moving rapidly upwards,—roughly speaking, towards the zenith, or more accurately, towards the sun. This, as I immediately afterwards ascertained, was about 11h 15m Greenwich mean time.

In investigating the phenomena of the free expansion of gases in the previous part of this paper, they had been considered as expanding, without receiving or giving out energy in any form; so that the equation taken to represent their condition was

This condition was realized in the early experiments of Mr Joule, where, by the sudden opening of a stopcock, air previously confined in one vessel was allowed to fill another also; but it is not exactly realized in the experiments now in progress by Messrs Joule and Thomson, for which the correct equation is

After some remarks on the peculiar difficulties which attend investigations into the functions of the eye, the author observed, that by far the most remarkable variety of colour-blindness, in a scientific point of view, is that which shows itself in the identification of red with black. This appeared to have been overlooked by previous observers, or at least only cursorily described. The probable causes of this neglect were noticed; and the author then proceeded to detail the experience of some twelve parties by whom various objects of a red, crimson, or scarlet colour were mistaken for black, and appeared, from the testimony of those who committed the mistakes in question, to have made neither a colorific nor a luminous impression on the retina. It was further shown, that though the fact had not attracted attention, the published cases of colour-blindness supplied examples of the same blindness to red; and that Dalton, although he had apparently ascertained his own freedom from the blindness in question, had incidentally supplied proof that the red alike of the solar spectrum and of coloured objects frequently appeared to him as dark or nearly black.

This instrument consists essentially of a little spherical bottle of thin brass, polished externally; a small exhausting syringe; a thermometer with ground brass stopper; and a brass clamp. The bottle has a diameter of 1 3/20 inch, and is capable of holding half an ounce. Its neck is attached to the syringe by means of a lateral screw, and is three-fourths of an inch high, and about three-tenths of an inch wide. The syringe is about five inches long, and has a diameter of eight-tenths of an inch. The stopper attached to the thermometer fits air-tight into the upper part of the neck of the bottle. The clamp is intended for securing the instrument to the sill of an open window, or to a table or other fixture in a room. Three drams of ether are then slowly introduced into the little bottle, and the thermometer inserted.