inquiry of this kind, in regard to phenomena falling within the perpetual observation of seagoing persons; yet, at the risk of stating what might be deemed common, I will venture to transcribe from my notes made with the phenomena before me the leading characteristics which engaged my attention. During the height of the gale (March 6th) the form of the waves was less regular than after the wind had for some time begun to subside. Though in many cases when the sea was highest the succession of the primary waves was perfectly distinct, it was rather difficult to trace an identical ridge for more than a quarter to a third of a mile. The grand elevation in such case sometimes extended by a straight ridge, or was sometimes bent as of a crescent form, with the central mass of water higher than the rest, and not unfrequently with two or three semi-elliptic mounds in diminishing series, on either side of the highest peak. These principal waves, too, it should be noted, were not continuously regular, but had embodied in their general mass many minor, secondary, and inferior waves. Neither did the great waves go very prevalently in long parallel series, like those retarded by shallow water on approaching the shore, but every now and then changed into a bent cuneiform crest with breaking acuminating peaks. On the following morning (March 7), after a second stormy night, wind SSW. (fine), we had a heavy and somewhat cross sea (from the change of wind from WSW. to SSW.) But the almost unabated magnitude of the more westerly waves indicated a continuance of the original wind at some distance astern of us. The gale had moderated at daylight, and the weather became fine; but as the sea still kept high, its undulations became more obvious and easily analyzed. At three in the afternoon, when about a third part of the greater undulations averaged about 24 feet from crest to hollow, in height, these higher waves could be traced right and left as they approached the ship to the extent of a quarter of a mile on an average, more or less. Traced through their extent, the ridge was an irregular roundbacked hill, precipitous often on the leeward side of waters. The undulations, indeed, as to primary waves, consisted mainly of these roundbacked

masses, broken into or modified by innumerable secondary and smaller waves within their general body. The time in which these waves passed the ship was now, on an average, about 15 seconds, the ship's speed being increased from 9 to 11 knots, and the obliquity of the ship's course to the direction pursued by the waves was three points. On the 9th, two days after the above condition of the waves-whilst the sea yet ran high-few waves could be traced continuously above 300 or 400 yards in extent along the same ridge. The crests often curled over, but none so as to reach the height of a 30 feet wave, and broke for a wide space, estimated at 50 to 100 yards in continuity.

Miscellaneous Notes and Suggestions.-The mode adopted in these researches of finding the height of waves is, said Dr Scoresby, I believe, quite satisfactory, and, observed with care and with relation to numbers or proportion of waves, as accurate as need be. The depression of the horizon, in respect to the elevation of the observer, is too small to form even a correction. As the horizon from the paddle-box 315 feet, had only a depression of 3′ 49′′, the distance of the visible horizon, as seen from this elevation, would be 4.45 statute miles, and the actual depression in feet due to the distance of the summit of the wave when the ship was in the midst of the hollow, could only be 0.18 foot, or 2.16 inches. Other modes of determining the width of a wave-or the extent betwixt summit and summit-much preferable to that described (the only available one I could devise) might easily be adopted, where the management of the ship was in the hands of the observer. In steam-ships, the simplest mode for high seas, perhaps, would be, altering the speed of the ship when going in the direction of the wave or against the wave; the ratios of the times of transit of wavecrests, under different rates of sailing of the ship, might yield results very close to the truth. In moderate-sized waves the plan adopted by Captain Stanley-whose observations I met with before this meeting-seem satisfactory. But in calms, or moderate weather after a storm-that is, for the determination of the velocities of less elevated waves—a variety of processes might be available."

The author referred, in conclusion, to the forms of wavecrests, and heights, modified by crossings, interferences, and reflections.

Mr Scott Russell said he felt a familiar interest in the results of Dr Scoresby's observations. The Section was aware that great doubts existed as to the actual heights of the waves of the open ocean. It was now past all doubt that waves 24 feet high, 30 feet high, 43 feet high, and with the swelling crest even exceeding 45 feet high, actually existed and were observed. From the observations which he had conducted many years since, he had ventured to draw up a table predicting the velocities of sea waves up to even 1000 feet from trough to crest in length. Although the apparatus which he had used did not enable him to experiment on waves which exceeded 16 inches in length,-yet from these pigmy waves it was most interesting to see how accurately the law was obtained; for in his table the velocity of a wave whose length was 600 feet was set down at 30 or 31 miles per hour, Dr Scoresby's actually observed velocity for this wave was 32 miles and a fraction.

Lord Northampton begged to remark, that this was one of the many instances of the value of the British Association as a handmaid to science. It brought together two such gentlemen as Mr Russell and Dr Scoresby, and showed the accuracy of the laws deduced by one from experiments conducted on a microscopic scale, by the test of others observed amid the sublime scene of the great Atlantic.

Professor G. G. Stokes read a memoir "On Metallic Reflexion," and another "On a Fictitious Displacement of Fringes of Interference."-Rev. Professor Powell" On the Refractive Indices of several Substances."

SECTION B.-CHEMISTRY, INCLUDING ITS APPLICATION TO AGRICULTURE AND THE ARTS.

President.-Dr CHRISTISON, V.P.R.S.E.

Vice-Presidents.-Dr GREGORY, Dr TRAILL, Dr DAUBENY.

Secretaries.-Mr R. HUNT, Dr G. WILSON, Dr T. ANDERSON. Committee.-Dr L. Playfair, Mr J. P. Gassiot, Professor Johnston, Dr J. Stenhouse, Mr J. P. Joule, Professor Voelcker, Professor Blyth, Messrs S. Ward, T. Pearsall, Professor Penny, Dr Gladstone, Mr A. Kemp, Dr D. Maclagan, Messrs J. Tennant, J. Young, H. L. Pattinson, H. C. Sorby, Dr Schunck, Professor Williamson, Dr R. D. Thomson, Dr Andrews, Professor A. Fleming, The Marquis of Northampton, G. Gladstone, Professor Chapman, Dr De Vry.

Dr George Wilson read a paper containing a few particulars concerning the late Dr Black.

This paper is too long to be given in full, and cannot well be abridged. It will be acceptable to those who take an interest in the biography of our men of science, and we perceive that it has been reported at length by the Literary Gazette for August 10, 1850. We shall only, therefore, mention that the paper contained the account of several curious particulars concerning Dr Black's habits and character not previously published. It also corrected two erroneous dates in the history of our celebrated chemist; the one that of the publication of his views on fixed air, which Dr Wilson proved, by the production of the copy of Black's inaugural dissertation, from the library of the Edinburgh University, to be 1754; the other that of his death, which, as Mr Muirhead has shewn, was in December, not November, 1799, when Black was in his 72d, not in his 71st year, as has generally been stated. In illustration of this paper, Dr Wilson shewed to the Section Black's blowpipe and balance, as well as the trough in which he prepared fixed air before his class.

Dr Daubeny read a Report" on the influence of carbonic acid on the growth of ferns." This was merely a statement that the inquiry on this subject was still in progress, and that no satisfactory results have as yet been arrived at. The ferns were now growing in an atmosphere containing one

per cent. of carbonic acid in excess above that ordinarily contained in air; and although it was thought similar ferns growing under the same conditions, but without carbonic acid in excess, were the most luxuriant, it appeared that they thrived well in this artificial atmosphere. Mr R. Hunt stated that he found the diversified influences of light materially to affect the quantity of carbonic acid which the plants could absorb without immediate injury.

Professor Voelcker read a paper on "the per-centage of nitrogen as an index to the nutritive value of food," which was highly important, as shewing the objections which apply to the present method of determining the nutritive value of food by chemical analysis. The nature of the paper, however, does not admit of abstract.

A paper was then read from Mr Henry Taylor, on "the chemical composition of the rocks of the coal formations;" and another by Mr J. P. Joule, F.R.S., " on some amalgams."

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Mr J. P. Gassiot, F.R.S., the well-known electrician, read a paper on "a peculiar form produced in a diamond under the influence of the voltaic arc." He exhibited to the Section a diamond which had been exposed to the intense heat produced by the voltaic battery when arranged as in the device for the electric light. The diamond had apparently been fused, but instead of changing into coke, as in such circumstances diamonds generally do, it had become a glassy mass, and seemed to consist of a multitude of small crystals adhering to each other. The diamond was examined with much interest and curiosity.

The last paper read was by Mr H. C. Sorby, F.G.S., on "the trimorphism of carbon," the object of which was to establish the fact that coke was in reality crystallised when very hard, and in the same form as the diamond, from which, however, it was stated to differ in crystallographic volume. Mr Sorby stated that he had also observed anthracite or blindcoal in the form of crystals, belonging to the square prismatic system.