At long intervals notices of circular crystals have appeared before this Society. In 1853 Sir David Brewster read a paper on the subject, which followed one by Mr Fox Talbot in 1836, and which again had been preceded by one from Sir David Brewster about twenty years before. It is not easy to account for these long intervals, unless they may be attributed to difficulty and uncertainty in manipulation, for except in very few instances the crystals observed by Sir David Brewster are of microscopic size, and, he remarks, require the perfection of optical appliances for their observation, and naturally so when crystals of the 200th of an inch in diameter are looked upon as of respectable size.

During the twenty-one years ending 1873, the maximum period of thunder with or without lightning, at Oxford, extended from about 9th April to the end of October, the middle of the period being the first week of July; the three highest days taken consecutively being those immediately preceding the summer solstice. During the five months from November to March, only thirteen cases had occurred during the period. Lightning, on the other hand, had its maximum period from May to November,—particularly during August, September, and October. The maximum period of hail was during the first six months of the year; whereas, during the second half of the year, very few cases occurred. The snow period extended from the middle of October to the middle of May,—most falling from December to March,—the absolutely highest month being March.

This Note does not refer so much to those great thunderstorms which extend over hundreds of miles in each direction, as to those small local storms which are often seen of from two to five or six miles only in diameter.

It refers particularly to those which are seen, in summer and autumn, to pass down the Tay valley. They almost invariably come from the westward, and I am told each is almost always accompanied by a storm of similar dimensions passing eastwards down the valley of the Forth. So far as I can ascertain, they seem both to commence almost abruptly somewhere in the district about Ben Ledi and Ben Lomond.

The objections to the use of sealed tubes are known to every practical chemist, and are a serious drawback to their employment. The chief of these are the time expended in the manufacture of the tubes, the amount of skill in glass-blowing required, the danger experienced in opening them, and above all, the fact that only a small quantity of material can be heated at one operation. Moreover, the same tube can seldom be used for more than three or four experiments, as each time it is sealed up its neck must be drawn out, and its length thus considerably decreased. These disadvantages were especially felt by me whilst preparing bromacetic acid, which was required in considerable quantities, and where as many as half a dozen tubes of bromine and acetic acid had to be heated before 100 grammes of the acid could be obtained. To obviate these objections I have had an apparatus constructed, which consists of a cylinder of glass, the walls of which are about half an inch thick. Its length is fifteen inches, its external diameter three inches, and its capacity about 600 cubic centimetres. At one end it is drawn out to a tube, whose aperture is only about one-sixth of an inch in diameter, though its walls are as thick as the rest of the apparatus. Originally this tube was provided with a stopcock, but at Professor Brown's suggestion, I have substituted a glass plate, which is ground fiat, and accurately adapted to the top of the tube.

At various times there have arisen supporters of one or other of two extreme hypothesis concerning the nature of what we define as force. These are the hypothesis of “action at a distance” and of “no action at a distance.”

According to the latter hypothesis, the centre of gravity of no body, however large or however small, can be moved from a position of rest, nor can its motion be altered in direction or amount, except by direct collision with another portion of matter.

In 1868 I presented to the Society, on behalf of Sir Charles A. Hartley, a memoir published by the European Commission of the Danube, on the improvement of that river, and at the same time gave a notice of the works designed by Sir Charles Hartley for effecting that important object. These works have now been completed, and Sir Charles Hartley has again asked me to present to the Society a second memoir published by the Commission, which brings the history of the works constructed under their charge down to the time of their completion in 1873.

Professor Heddle read a paper on the “Rhombohedral Carbonates occurring in Scotland,” the first of a series of Chapters intended to embrace the analytical results of an investigation of all unknown or insufficiently determined Scottish species.

In this paper many analyses of the carbonates were submitted; and the pseudomorphic changes taking place in these were referred to in a special manner.

The object of this communication is to submit to the notice of the Society two little inventions of mine, which, whatever may be the degree of originality which they can claim, will, I venture to hope, prove useful additions to the catalogue of chemical-laboratory appliances. The one is a new form of the precision balance, which pretends to execute exact weighings with a hitherto unattained degree of rapidity; the other is a contrivance for maintaining a constant pressure in a supply of gas, and thus making it possible, with comparative facility, to keep, say an air-bath, for any length of time, at a constant temperature.

I wish to direct attention to a simple improvement on battery cells, whereby porous cells are dispensed with, and the inconveniences of gravity batteries avoided.

In this communication the authors gave descriptions of several new or imperfectly understood forms of Palæozoic corals. After giving a general account of the method of investigation employed by them, the genus Heliophyllum, Hall, was discussed at length. The external structure of this genus is very peculiar, and it was shown that the genus is not by any means as nearly related to Cyathophyllum as has been generally believed.

The recent revival by a distinguished Celtic scholar of the theory of Laing that Macpherson's Gaelic Ossian is a translation from the English, affords an opportunity of examining that question in a more strictly philological fashion than it has hitherto had the fortune to enjoy. Parts of the question were no doubt touched by Mackenzie in the Report of the Highland Society, published in 1805 by Graham in his dissertation on the authenticity of Ossian, by Dr Clerk of Kilmalie, the distinguished author of the new version of Ossian in the late splendid edition published at the expense of the Marquis of Bute; but systematically grappled with the question has never been.

The difficulties in the way of dredging at Madeira are many and considerable. This has probably prevented any of this work having been done since the publication of Mr Macandrew's list of Mollusca, presented to the British Association in 1854. The author having dredged for several years at Madeira, confirms Macandrew's generalisation of the Mediterranean character of the Mollusca— excludes 12 of Macandrew's named list as having crept in by mistake, and to the 115 remaining species identified by Macandrew as Madeiran has added 200 to 250 more, making nearly 400 in all, of which 80 or perhaps 100 are probably new. These he hopes soon to publish.

What appears to be an entirely new foot-print has lately been found in the red sandstone of this district. I have seen many of the foot-prints from the various quarries in the neighbourhood, but have not before observed this one, nor is it like any figured in Sir William Jardine's splendid work on the “Ichnology of Annandale.” The foot-prints in question were found in a bed about 20 feet from the surface, at Locharbrigg's Quarry, three miles from Dumfries. They exhibit the usual large hind and smaller fore foot; the impression of the hind foot measures ′·5 × 2′·6, the fore foot 2′·3 × 1′·9; the stride of the animal appears to have been about 10′. The impression of the hind foot does not interfere with that of the fore foot, as is the case with several of the foot-prints figured in Sir William Jardine's work, the interval between them being 2′: the hind foot, therefore, must have been put down in the rear of the fore foot when the animal was walking. The impression of the foot shows five toes, the thumb being placed far back. The most characteristic features in these foot-prints are the well-developed claws, and the oblique position of the toes, i.e., they are placed to march one behind the other. In almost all the foot-prints I have seen, where the toes can be made out, the middle one appears the most prominent; this foot-print is markedly distinct in this respect.