The sea-weeds examined by the author, reported on in this paper, were the following:—Carrigeen Moss (Chondrus crispus), Dulse or Dylisk (Rhodymenia palmata), Sloke or Laver (Porphyra laciniata), Tangle (Laminaria digitata), Doughlaghman (Fucus vesiculosus).

The author states that the results of the Trigonometrical Survey of Great Britain are nownearly ready for publication, and that he has deduced from them the most probable measures which they afford of the length of a meridian, and the figure of the earth.

After determining the most probable spheroid from all the astronomical and geodetical operations in Great Britain, it has been found that the plumb-line is sensibly deflected at several of the trigonometrical stations; but in almost every case the physical cause of such irregularity may be with probability inferred.

In this paper the author showed that, a and e being independent probabilities of the same event, the expression a + e—a e, given in the article Probability in the Encyclopædia Metropolitana as the value of their combined force, was erroneous.

The intention of the author in this communication is to recommend the daily determination of the weight, by direct means, of some considerable bulk of atmospheric air. This subject has become of interest to medical observers, owing to the belief which has arisen, on hardly sufficient grounds, that during the prevalence of epidemics the air is of greater weight than usual.

The author gave a simple demonstration of the proposition, that an = bn + cn is impossible, when n > 2, and either of the numbers, a, b, c, a prime number.

In this inquiry, which is an extension of an investigation published in the Transactions for last year, the author examines the connection which has been said to exist between chinoline and quinine, and shows that they bear no simple relation to each other. He states, also, that the supposed analogy between the action of heat on quinine and the hydrated oxide of tetramethyl-ammonium does not exist, and that the assertions which have been made regarding the possibility of the formation of quinine from the leukol of coal-tar are founded on error.

In 1849 the learned Swiss philosopher Wartmann stated, in his “Deuxième Mémoire sur le Daltonisme”, p. 40, that “the eye arrests the chemical radiations which accompany the more refrangible rays.” He founded this conclusion on experiments made with guaiac resin; but as this substance is by no means very sensitive to actinic influence, it seemed desirable to test the question whether the eye can transmit the chemical rays of light, by an appeal to those highly impressible actinolytes (as they may be called) which the recent progress of photography has revealed to us.

While the prismatic spectra of the blue portions of an oil-lamp or coal-gas flame, exhibit a number of bright lines, separated by dark intervals, the spectra derived from the bright light of these flames are perfectly continuous. Apparently inconsistent results are in like manner obtained when the flames of different compounds of carbon and hydrogen are compared. Thus, lines are easily seen in the spectrum of the flame of alcohol, which are invisible in that of the flame of oil of turpentine.

After adverting to previous publications on the subject by himself and Professor W. B. Rogers, the author of the paper began the enunciation of the laws of structure of disturbed tracts of strata, by stating the general proposition that in all districts where thestrata have been displaced from the original positions or levels in which they were deposited, they invariably have the form of one or many waves, even where, from a flatness of the undulations, they seemed to retain their original horizontality.

One object of the Laboratory of the Industrial Museum is the prosecution of investigations likely to throw light on the economic value of materials employed in the useful arts. It has been impossible this winter to do more than make a small beginning by instituting an examination into the properties of certain of our building stones; and as the results obtained in the case of the sandstone of Craigleith Quarry have an interest for geologists as well as for architects and builders, they are laid before the Society, as all similar results of any scientific value will be in future.

The Council of the Royal Society have, in the course of the last year, taken into serious consideration the state and prospects of the Society, and have deliberated upon many propositions having for their object to render our ordinary meetings more interesting, and generally to increase the efficiency and usefulness of the Society. Among other schemes of this nature, they have adopted one, in conformity with which I have now the honour of addressing you.

The paper contained a series of observations on the development of the embryo in the salmon, made on ova procured from an establishment for the artificial propagation of this fish, at Overton, on the river Dee. The author's observations commenced about the 37th day after impregnation, and were continued from that period to the time when the vitellus becomes finally absorbed.

In this paper the author, after a short general account of the different forms in which contractile tissue occurs in the human body, describes at greater length the discovery made in 1847 by Professor Kölliker, that involuntary muscular fibre is capable of being resolved into nucleated elements, supposed to be of the nature of elongated cells, and hence termed “contractile” or “muscular fibre-cells.”

In this communication the author first gives an account of the occurrence of the Vendace (a fish hither to supposed to be confined to the lochs of Lochmaben in Dumfries-shire) in two of the lakes of Cumberland, viz., Derwentwater and Bassenthwaite Lake, in each of which it seems to be pretty abundant, and to have been long known to the boatmen; secondly, he offers some speculative suggestions as to the diffusion of species in the instance of this fish, giving the preference to that presuming that its transfer might have been accidentally effected by the impregnated ova being conveyed by aquatic animals

The British possess three colonies on the western coast of Africa: Gambia, 2490 miles from England, in latitude 13° 30' N., longitude 14° 40' W.; 500 miles south, Sierra Leone, in latitude 8° 30' N., longitude 13° 10' W.; and, 1500 miles down in the Bight of Benin, Gold or Cape Coast Castle, in latitude 5° 5' 25” N., longitude 1° 12' 45” W.

The author remarks, that although there are upwards of 280 writers on the Crinoidea, yet there is no class of ancient animals so much misunderstood. These animals have not merely played an important part in the system of creation as regards animal life, but they have also modified the physical condition of the globe. They are found abundantly in limestones, both of the Silurian and of the Carboniferous epochs, attaining their maximum in the latter.

The method for the solution of questions in the theory of probabilities which is applied in this paper, is that which was developed by the author in a treatise entitled “An Investigation of the Laws of Thought, on which are founded the Mathematical Theories of Logic and of Probabilities.”

In two papers, read before this Society, and subsequently published in the Microscopical Journal, I described and figured a large number of new species of Diatoms, chiefly marine, which I had found in the Glenshira sand.

This sand was deposited by the Dhu Loch of Glenshira, at a period geologically recent, when that lake occupied a higher level than it now does, and extended about two miles farther up the valley. That the Dhu Loch at that period, as well as now, communicated with Loch Fine, so that at high tide the salt water flowed into the lakes, while at low water the current, as in a tidal estuary, flowed outwards, is proved by the fact, that the sand then deposited contains more marine than fresh-water species.