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Mr. Snow Harris. We may also notice Mr. Nasmyth's application of the theory of definite proportions to the explanation of the theory of clouds, and Dr. Lamont's report of a great system of meteorological co-operation about to be carried on, on the Continent, from the Pyrenees to the frontiers of Persia.

These constitute comparatively new subjects of inquiry, and not less interesting from that circumstance. This year a supplemental report of the committee on waves was read by Mr. Russell, and referred to a third inferior class of waves, which were designated as capillary waves, in resulting from the same causes which give rise to the forces of capillary attraction. There were also some remarkable admeasurements given of the comparative length and velocity of common waves, which corresponded so closely with the Newtonian law on that subject as now to entitle the common wave to be distinguished as the Newtonian. In an able communication made by the same gentleman, on an abnormal tide wave in the Firth of Forth, it was stated, that from the peculiar form of that Firth, the tides of which are principally due to the great northern tide wave which comes round the north of Scotland, curious results were produced in the form of the curve, the level of the low water at Alloa being, for example, far above the level of the high water at Crail; and the tide at Stirling (although the general range in the Firth was only sixteen feet) rose to the extraordinary height of thirty feet above the the level of low water at the lower part of the Firth. Mr. Rook read a memoir on the tidal phenomena in the bay of Fundy and the river of La Plata, and Mr. Walker, of Plymouth, made a communication on the movement of oceanic waves in that harbour.

To be classed as such, comes one, perhaps, of the most remarkable communications made at this meeting of the association. It was communicated by Professor Bessel, as the discovery of Professor Moser, of Königsberg, and related that, when a black plate, either of horn or agate, is placed below a polished surface of silver, at the distance of one-twentieth of an inch, and remains there for ten minutes, the latter receives an impression of figures &c. engraved on the former, which may be rendered visible by exposing the silver plate to vapour, either of water, mercury, or of other substances. This process takes place at midnight as well as mid-day, and the picture on the silver surface is to be called into sight even by a breath. Sir W. Hamilton called it scotography; but, Sir J. Herschell asked, might it not be thermography?

The most interesting communication made in chemical science was Professor Liebig's report on organic chemistry, applied to physiology and pathology. The mere consideration of such a subject opens a new and wide field of inquiry. The report contained a vast number of curious and remarkable facts, many of which apply themselves to the interests of everyone, and to the daily occurrences of life. We regret much, then, that our limits do not allow us to give an analysis of a paper of so much public value. In theoretical chemistry we may rank Professor Schönbein's communication on the electrolysing power of a simple voltaic circle. The result of various experiments made by the author, going to establish the fact, that voltaic effects may be produced without the solution of a metal, the usual source of voltaic actions, but by nitric and other acids. Also Mr. Joules' communication, in which he endeavoured to account for the heat evolved by the combustion of certain bodies, on the hypothesis of its arising from resistance to the conduction of electricity between oxygen and the combustibles at the moment of their union. Another interesting communication in chemical philosophy was Mr. Mercer's attempt to explain, on ordinary chemical principles, some effects hitherto described as catalysis. Perhaps the most important communication in practical chemistry was that of Dr. Playfair, in which he made known certain new oxides of metals, of the magnesian family. This memoir was of high importance to chemical geology. Next came three papers by the venerable Dr. Dalton, who was the lion of the Manchester meeting, on phosphates and arseniates; on microcosmic salt, and on a new and easy method of analyzing sugar. There were also papers on the influence of light on the germination of seeds, by Mr. Hunt; on the modes of production of sulphuric acid, by Mr. Blyth; on agricultural chemistry, by Dr. Daubeny; on Kakodylic acid, by Mr. Bunsen; and several others of practical importance. There was only one mineralogical communication, and that was by Professor Haidinger, being an account of the mineralogical and geological museum of the Imperial mining department, and which eloquently extolled the effects, in arresting the