object of Mr. Kerr's plan is to ascertain what is the real area of the mouth, or surface exposed during the shower, and so to find the true quantity impinged on a given surface. The instrument is also constructed to show the quarter from which the rain comes. To accomplish these ends, he employs two cups, which are so placed that the planes of their mouths make a right angle with each other. The mouth of the one is vertical, and the mouth of the other is horizontal. We have thus all the varieties which can happen between 0° and 90°, or between a perpendicular fall of rain, and one that is blown parallel to the horizon. The cups are each of them connected with a tube, which conveys the water to the recipients below, and the whole is attached to a wind-vane, which turns round upon a strong iron rod. By this means the mouths of the cups are always kept in a proper position, fully exposed to the shower. The iron rod which supports the whole passes through a square hole in the middle of a cistern-frame divided into 16 spaces, and containing two concentric sets of cisterns. The inner cisterns receive the drops which fall from the tube connected with the vertical cup, and the outer cisterns receive the drops which fall from the tube connected with the horizontal cup. As the cisterns remain fixed, and the gage tubes move with the vane, it is evident that the water can only drop into that cistern which happens to be under the end of the tube at the time, so that we can easily tell what way the wind blew during the shower. Thus if we find water in the south cistern, the vane above must have pointed in that direction. The quantity of water found in each cistern is afterwards poured into a graduated glass tube, and an account of the contents kept in a book having a column ruled for each cistern.

In order to find the true surface exposed, it is necessary that we should have the angle at which the rain is impinged on the cups. This angle is found by comparing the whole quantity of water in the' cisterns of the horizontal gage with the whole quantity of water in the vertical gage. Thus suppose we find an equal quantity in each, then the rain must have fallen at the angle of 45°, for at that angle the cups present equal surfaces. But if we find more water in one set of cisterns than in the other, the rain must have fallen at a greater angle on that set which contains most; and the angle may be found by the help of a table constructed to show the obliquity which corresponds to any given inequality of water in the recipients.

This rain-gage, in Mr. Kerr's opinion, will not only be enter taining to the meteorologist, but also useful to the farmer, who, by a series of observations, may be able to determine more accurately the climate of this farm. It will point out to him what places require to be most secured, when he is constructing places of shelter for cattle, hay, or corn-stacks, planting trees, and many other rural operations.

At the meeting of Jan. 6, Dr. Macknight read a mineralogical description of Ravensheugh, on the west of East Lothian. It is

composed of red sand-stone, clay-iron-stone, and red marl, which are associated with clink-stone, clink-stone-porphyry, basalt, and trap-tuff.

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Jan. 20. The Secretary read a paper by Dr. Grierson, entitled, Mineralogical Observations in Galloway. It was shown that there are three principal granite masses in Galloway, all of them situated in districts principally composed of transition rocks. In this paper the Doctor described the upper, or Loch Doon, granite. This mass of granite appears to bear the same relation to the stratified country which he formerly found the middle, or Dee, mass to have. The grey-wacke or grey-wacke-slate were nowhere observed in immediate contact with the granite, but every where separated from it by a kind of compact gneiss. The strata of this rock observe the usual direction, not varying above four or five points, and their ends on the N. E. side of the granite run directly towards it. On the E. side of the granite they meet it in a conformable position, and are either nearly vertical, or dip from it. They are much more highly inclined than those which meet with the Dee granite. The Doon granite is in general of the same texture with that of the Dee. But there are two peculiarities with respect to its relation to other rocks; one, its containing numerous and large apparent fragments of gneiss; the other, the occurrence of beds of felspar-porphyry in it.

Feb. 3. Mr. Campbell, of Carbrook, read a paper on the upright growth of vegetables. After stating the grounds on which he concludes that gravitation is the principle to which perpendicularity is to be ascribed, and examining the hypothesis of Mr. Knight, as to the mode in which that principle operates (which he conceives to be erroneous), Mr. Campbell proposed a theory founded on the law of resisted attraction, by which he considers all ascents from the centre to be regulated. The evaporation which constantly accompanies. vegetation, and the buoyancy produced by the formation of gaseous vapour, afford, according to his view, a field for the operation of this law; and although some effect may be produced by the upward pressure of hydrogen in a free state, he attributes to the buoyancy of gaseous vapour the chief agency in the upright growth of vegetables.

At the same meeting the Secretary read a communication from James Wilson, Esq. containing remarks on the characters of thes emberiza cirlus of Linnæus, accompanied with a specimen of the bird shot near Edinburgh...

Feb. 17.-Professor Jameson read a communication transmitted by Mr. Scott, Receiver-General of the Isle of Man, concerning the skull and horns of an extinct species of elk found in a turf bog in that island. The horns differ considerably from those of the Irish elk.

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On the same day a communication from Dr. H. Et Holder was read, concerning the effect of the juice of the papaw-trece (caricab papaya) of the West Indies, in lessening the cohesion of muscular

fibre. Residents in the West Indies avail themselves of this property, to intenerate their butcher's-meat and poultry. For this purpose it has been found that even the exhalation from the stem and leaves is sufficient, and the meat is accordingly hung for about half an hour on a bough of the papaw-tree. The wholesomeness of the meat is not affected by this process. Vauquelin examined the papaw juice, but found nothing remarkable in it; but the subject of its intenerating effects requires to be further inquired into. At present we do not know what share the tropical temperature may have in these results, nor how long after the animal is killed these effects may be produced.

March 2.-There was read the first part of a paper by Mr. Stevenson, civil engineer, on the probability of a change gradually taking place on the level of the German Ocean. In this first part Mr. Stevenson treated only of the wasting effects of the tides upon our shores. He mentioned that in the course of making professional inquiries regarding the impression which the tidal waters of the Frith of Forth are making upon some of the most valuable properties situated upon its banks, he was led to compare these with other observations that have occurred to him in his extensive intercourse with the shores of about one half of Ireland, and the whole coast of Great Britain from Shetland to the Scilly Islands. In doing this he began with the shores of the Frith of Forth, and then proceeded northward along the eastern coast to the Moray Frith, Caithness, and the Orkney and Shetland Islands; next slightly noticed the Lewis, and the western parts of Scotland; then the eastern shores of England, and the British and St. George's Channels. All these places afford many striking examples of the wasting operations of the sea upon the land.

These effects of the sea are not confined to the shores of the German Ocean and the British Channel; for the wasting of the land is no less remarkable in St. George's Channel and the Irish Sea, including the coast of Ireland on the one side, and on the other the shores of Wales, Lancashire, Westmoreland, and the counties of Dumfries, Kirkcudbright, and Galloway, where neither the rocky coasts, and exposed situations of the Islands of Anglesea, Man, Copland, Craig of Ailsa, and the Islands of Cumbrae, nor the sheltered and alluvial shores of the British Channel, are exempted: even the indentations of the coast at Dublin Bay, Liverpool, and Lancaster, and the more extensive Friths of the Solway and the Clyde, are subject to the unvarying destructive effects of the sea upon the land. He concluded that the disintegrating and wearing effects of the waters of the ocean are general. Whether we contemplate its effects upon the land by the immediate and powerful impulse of the waves at the base of a rocky shore, or, with the elegant and profound illustrator of the Huttonian theory, trace it in the form of rain, rills, and torrents, in the higher regions, we find its effects all tending to one unvarying principle, the degradation of the land, and consequent tendency to filling up at the bottom of

the sea; while at the same time, from the magnitude and extent of the surface, and other occult causes, we are not aware of the elevation of its level in any sensible degree. That Almighty Being who hath said, "Hitherto shalt thou come, and no further," has, with infinite wisdom, created a kind of compensating power to counterbalance the seeming conflict of the elements of earth and water: for while the ocean appears to be extending its surface, it seems also probable that the quantity of its waters upon the whole are lessened, that part of them undergoes a complete and permanent change of form after the process of evaporation; and that the earthy particles continually accumulating, at least to a certain depth, at the bottom of the sea, have a direct tendency not only to preserve an uniform level, but even in some instances to make the water overrun what we have been accustomed to consider its boundary.

March 16.-There was read an interesting memoir of the late Dr. Walker, Professor of Natural History in the University of Edinburgh, containing an account of his mineralogical studies, and of his systematic arrangement of minerals.

ROYAL INSTITUTE OF FRANCE.

Account of the Labours of the Class of Mathematical and Physical Sciences of the Royal Institute of France during the Year 1815. PHYSICAL DEPARTMENT.-By M. le Chevalier Cuvier, Perpetual

Secretary.

(Continued from p. 315.)
BOTANY.

M, Delabillardiere, who has already published so interesting a work on the plants which he collected in New Holland, when he accompanied the late Entrecasteaux in his expedition, has begun to give an account to the Class of those which he found in New Caledonia. This steep island, uncultivated as it is, and inhabited by unhappy cannibals, produces a great number of fine plants. M. Delabillardiere found in a few days 29 new species of fern, 12 of which are entirely new to the botanist, and have been found nowhere else. The others grow likewise in the other islands of the South Sea; and M. Delabillardiere gives a list of them, to elucidate geographical botany. He arranges these ferns according to the method of Dr. Smith, making some corrections in it. The very accurate figures with which his descriptions are accompanied will give to botanists a complete idea of these important additions to their science.

Every person is acquainted with the aquatic plant called duckmeat, and by botanists lemna. Th able and swimming vegetable covers with its green follwaters of almost

every country; but the flowers and fruit of this small and singular plant have not been examined with sufficient care.

M. le Baron de Beauvois is the first botanist who has been fortuDate enough to collect ripe grains, and to make them germinate. He has followed the lemna thus obtained during its whole progress, and has completed its history, which Ehrhardt and Wolf had only sketched.

It results from the observations of M. de Beauvois that the flower of duckmeat is hermaphrodite, with an envelope which is entire, with two stamina which unfold themselves in succession, with a single style, with a supertor ovarium, which becomes an unilocular capsule, splitting circularly at the base, and containing from one to four seeds, which germinate like monocotyledinous seeds, but with very peculiar circumstances, the most remarkable of which is, that: the parts considered as the radicle and plumula separate from the first leaf which they produce, and leave it alone to push out roots and other leaves.

Another species of organised being, which covers, and often fills stagnant waters, is the conferva, consisting of a mass of green filaments, sometimes similar to a sort of felt, which some naturalists have wished to assign to the animal kingdom. Their propagation is a good deal different; and some of them, whose filaments are at first disagreeably uniform, swell at intervals, and produce knots from which new filaments proceed. This has induced M. Vaucher' to give to these species the name of prolifera. But this botanist warns us not to confound with these filaments springing from the plant itself certain parasitical confervæ which attach themselves to other confervæ, and which have the same appearance.

M. Leclerc de Laval, Member of the Chamber of Deputies, and a very assiduous observer, has presented to the Class a memoir, from which it appears that no other filaments except these parasitical ones exist, and that the propagation of the confervæ, improperly called proliferæ, takes place in the same way as in those called conjuga, by the concentration of the green matter contained in each interval between two cells into an isolated globule which issues from the plant at a certain time, and fixes itself on the first body it meets with in its fall; and, after having thrown out some filaments in order to fix itself, developes a long series of cells.

The author would give to this kind the name of autarcite, instead of prolifera, which from his observations is improper. But as M. Desvaux, from other considerations, had given them the name of cyrtinus, in a memoir presented more than a year ago, it has been thought unnecessary to introduce a new change in the nomenclature..

M. Henri de Cassini had presented to the Class in 1812 a memoir on the style and stigmata of synanthereæ of plants, usually said to possess a compound flower, and another on their stamina. Towards the end of 1814 he presented a third paper, of which we could not give an account in our last analysis, because the report concerning