that all plants are avoided by animals when in flower or seed, but when the remark is limited to annuals and biennials, it will hold almost universally. For even snails and slugs, those indiscriminate devourers, will not in this case touch a leaf.

FORM AND ASPECT OF MOUNTAINS.-Most of the principal mountains have one of their sides very steep, and the other gradually sloping. The Alps may be instanced as an example, having a much more abrupt descent on the side of Italy, than on that of Switzerland; the Pyrenees, again, are steeper towards the south than the north, while the chain of Asturias, which branches westward from the Pyrenees is just the reverse. Mount Taurus, in the part where it approaches the Mediterranean, and the Dardanelles, is abrupt on the south, but in Armenia, it has a rapid descent northward. The mountains of Scandinavia are steeper towards the west and north-west, than the east and south-east; and the Ghauts, in Hindostan, are in like manner precipitous on the west, and sloping in the opposite direction. In all these chains, the steepest side is found to be that which is nearest the sea, and consequently their inclination is most gradual towards the interior of the country in which they are situated.

OCTOBER.

MIGRATION OF WILLOws.-In the Life of Lord Kanes, the following singular statement is given on the authority of Sir James Nasmith.-A number of willows had been frequently cut over at about eight or ten feet from the ground; their trunks, about fifteen inches in diameter, generally open on one side, and so much decayed that scarcely any thing remained but the bark and a small quantity of alburnum. These tops were furnished with fine shoots round their edges, which shoots had put out roots in great number, from the part where they were connected with the tree. These roots running down, some on the outside of the old trunk, and some on the hollow inside, until they reached the ground into which they penetrated, and until they had attained that point, made no attempt to put out lateral shoots or fibres. It is added, that the size of the roots by which this migration was performed, was generally about the thickness of a walking cane; and that, in their way down, they clung so closely to the old stem as to have impressed a groove in which they lay.*

* Appendix, No. 2, p. 40.

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It would be presumptuous in us to controvert, in a peremptory manner, a fact which we ourselves had not witnessed; yet we cannot help inferring that the alledged descending and migratory roots were nothing more than those cryptogamic plants (Rhizomorphæ), whose resemblance to roots would deceive those not acquainted with them. We have found these very common near London, branching out most extensively under dead bark, and even through the whole substance of decayed elms and willows. It may be remarked, that nothing is said by Sir James of young scions springing from these alledged roots.

MOVEMENTS OF SHELL-FISH.—The fresh water muscles, which are common in rivers and canals, are not, as might be supposed, immoveably confined to the spot where they may chance to be produced, as any person may convince himself by placing a few of them in a vessel of water. In such circumstances they will soon be seen to approach or separate from one another. The organ with which they effect these movements is of a fleshy substance, about two-thirds of the length of the shell, and thrust out through the opening near its middle. This foot, as we may term it, is about half an inch broad in the larger shells, and sharp at the point. In order to move themselves from place to place, they thrust this organ under the shell, applying it with a quick motion to the bottom of the place where they lie, by which means they can not only change their place, but turn themselves upside down.

FLIGHT OF BIRDS. - Swallows, and some other birds of passage, begin to congregate previous to undertaking their distant migratory expeditions. Their capa

bility of performing flights much longer than there is any necessity for supposing, may be proved by numerous facts. Even a sparrow has been calculated to fly at the rate of not less than thirty miles per hour, and many experiments prove that the eider duck can fly ninety miles in the same time. The common kite (Falco Milvus), has been observed to pass, without great exertion, over a space of a quarter of a league in a minute, and it could fly with ease from Cape Pruth to the Land's End in a single day. M. Audubon, the distinguished ornithologist, has shot the passenger pigeon of America, and on dissection, found its stomach full of fresh rice, which, to have resisted the digestive process, must have been swallowed not many hours preceding its death, but could not have been obtained within 800 miles of the place where it was killed. Though the nightingale, the willow-wren, and other birds of passage, fly with only half the swiftness, they may easily arrive in most parts of the south of Europe, or the north of Africa, in a few days.

MIGRATIONS OF THE CHAFFINCH.-As the summer birds of passage are now departed or departing, our winter visitants are beginning to flock in from the north. A very singular peculiarity in these migrations was first discovered by Linnæus in the chaffinch (Fringilla Spiza, RENNIE), of Sweden, the males migrating while the females remain stationary. It has been said that this occurs partially even in Britain with respect to the same bird. In the case of other migratory birds, it is remarkable that the males generally arrive first, preceding the females by several days, a circumstance

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which the bird-catchers know how to take advantage of.

The migrations of the different sexes appears to be by no means peculiar to the chaffinch; and hence, the epithet of widow or bachelor (Celebs), given to it by Linnæus, is inappropriate, more particularly as the bird is so remarkable for the neatness and beauty of its nest. It has therefore been deemed adviseable to substitute Aristotle's name of Spiza. Among other birds, whose sexes separate during winter, Selby mentions the snowfleck (Emberiza nivalis), and there can be little doubt that it is chiefly, if not entirely, the cock redbreast which winters near our houses, the hens either retiring from the island or haunting more wild and solitary localities. In the case of most of our summer visitors again, such as the nightingale and the whitethroat, the cock birds always precede the hens in their arrival by one or two weeks.

THE FALL OF THE LEAF.-It is not enough to account for the fall of the leaf to say it falls because it is weakened or dead; for the mere death of a leaf is not sufficient to cause its fall, as when branches are struck by lightning, killed by a bleak wind, or die by any similar cause, the dead leaves adhere tenaciously to the dead branch. To produce the natural fall of the leaf the branch must continue to live, while its leaves die and are thrown off by the action of its sap vessels. The change of temperature, from hot to cold, seems to be one of the principal circumstances connected with the death and fall of the leaf. Hence it is, that European trees, growing in the southern hemisphere, cast