tance from one another, and in succession, under their original form. Nature, then, does not produce any new organ in the formation of the calyx; she only assembles together and modifies organs already known to us; but, in accomplishing this, she has already made great progress towards the end.

FORMATION OF THE COROLLA.

39. We have seen that the formation of the calyx is due to the presence of the more refined juices, which have been gradually purified in the plant; and, the calyx itself becomes, in its turn, an organ adapted to affect a more complete purification. To convince ourselves of this, we need only reflect upon the mechanical action of the organs, which compose it; the delicate vessels, which, as we have already remarked, are, found in it, in a state of extreme contraction, by this means become very well adapted to effect a more subtle filtration.

40. We have been enabled to observe, on more than one occasion, traces of the transformation of the calyx into the corolla; for, although the former, ordinarily, preserves the green colour of the leaves, nevertheless, this colour is often changed in the margin of the extremities, and upon the sides of the calyx; it sometimes happens, even, that its internal surface is coloured, while its external surface is green; and, this colouration appears, always, accompanied with a finer and more delicate aspect. It gives rise to calices equivocal in their appearance, which may be, at pleasure, taken for a calyx or a corolla.

41. We have remarked, that, from the cotyledons upwards, the plant, in growing, manifests a tendency towards the expansion, and complete developement of its leaves, and, more particularly, towards augmenting the extent of their surface, by a more complete expansion of their margins: in the formation of the calyx, on the contrary, there is an approximation of these margins and a contraction of the organ. The formation of the corolla is due to a new expansion. The leaves of the corolla, or the petals, are commonly larger than the leaves of the calyx, or the sepals; and, it may be observed, that, if the organs are contracted in the calyx, they expand anew in the corolla into ramifications, rendered infinitely more delicate by the influence of the purer juices that have undergone a new filtration in the calyx, and, they then appear under the aspect of organs totally different. Their delicate tissues, their brilliant colours, the perfumes that they exhale, would render their origin perfectly irrecognizable, were we not able, in some extraordinary cases, to take Nature by surprise.

42. Thus, for example, we meet, in the calyx of certain Pinks, with a second calyx, often entirely green, which resembles a monophyllous calyx; but the lacerated, more delicate, and coloured margins of which display the commencement of a corolla; and, we are obliged to recognise the affinity of the corolla with the calyx.

43. The affinity of the corolla with the leaves of the stem demonstrates itself also, in several modes; for, we find in several vegetables, leaves more or less coloured placed much lower than the inflorescence, and others, which are wholly coloured, in the vicinity of the flowers.*

44. It frequently happens, also, that nature passes over, as it were, the calyx, in order to come immediately to the formation of the corolla; and, in these cases, we also find the leaves of the stem passing into the state of petals. Thus, among the tulips, leaves, almost entirely coloured, and scarcely differing from petals, are frequently found upon the stem. This transformation is, however, much more evident, when these leaves are half green and fixed to the stem, whilst the other half, coloured, rises with the petals, and rivals them in splendour.

45. It is probable that the colour, and the odour, is due to the presence of the pollenic matter, or male semen, probably also this is not found, in them, perfectly mixed, and tempered with the other juices, so as to be in a fit state for secretion;

* Examples, Hortensia, and several Sages, (Sauge Hormin, Sauge Splendide.) VOL. I. H

and, the beautiful appearances of the colours induces us to think, that the matter, which fills the tissue of the leaves, is already very pure, but that it has not yet attained the degree of purity, to which it arrives, when the organ becomes white.

FORMATION OF THE STAMENS.

46. The presence of the male semen in the petals becomes much more probable, when we call to mind the great analogy of the petals to the stamen; if the affinity of all the other lateral parts with one another were as evident, and as generally admitted, the present essay might appear superfluous.

47. In certain cases nature displays to us, gradually, the transformation of the petals into stamens: for example, in the Canna, and in several plants of this family. A true petal, and one, whose form is but slightly altered, contracts at its upper extremity, and becomes an anther, to which the inferior part of the petal serves as a filament. The flowers, which are frequently doubled, display to us every step of this transformation. In several species of roses we find, among the ordinary petals of the half doubled flowers, other petals, the edges or middle of which are contracted: this contraction is determined by a small swelling, which more, or less, resembles an anther, and, the petal approaches as much to the form of stamens.* In some double flowered Poppies, anthers, perfectly formed, are attached to petals very slightly deformed, in others, certain swellings, analogous to anthers, contract the margin of the petals.

49. When all the stamens are changed into petals the flowers become sterile : but, should some stamens be formed, notwithstanding the doubling of the flower, fecundation will still take place.

50. Thus the stamen is formed, when the organ, which we see under the form of a petal, and in its state of expansion and dilatation, shrinks, contracts, and assumes a more delicate and slender appearance. The observation, which we have already made, is again confirmed, and renders us more attentive to this alternate dilatation, and contraction, which nature employs as the means of obtaining her end.

(To be continued.)

[17]

SUBTERRANEAN COURSE OF THE RIVER OUGNA.

From the Norwegian "MAGAZIN FOR NATURVIDENSKABERNE.”

THE river Ougna, which flows through the district of Sparboen, in the province of Tronhiem, has its source in the Gulstad mountains, near the boundary line between Norway and the adjoining province of Jemteland in Sweden. It runs from East to West for about thirty-five English miles through the valley of Ougndal, and falls into the bay of Tronhiem near the small hamlet of Steenkiær, which was in former times a port of considerable importance, but has, since the erection of the city of Tronhiem, become an insignificant place. About seven miles from its source, this river passes the farm called Gulstad, (which is well known, owing to its vicinity to the now deserted copper-mines of Gulstad,) where it displays a phenomenon, which is probably the only one of its kind in Norway.

At a short distance to the east of the spot where the ruins of the old copper works are situate, the river precipitates itself, in a succession of small cascades, into an abyss, and suddenly disappears. The surrounding territory is covered with copses, interspersed with cultivated land, under which the river flows unseen for the distance of about 300 paces, when it issues from a rocky cavern in a gentle stream. When the water is low, it is practicable for a man to walk some paces up the cavern, with a torch, on the brink of the river. The depth between the soil above, and the top of this natural arch, varies from 50 to 60 feet. The intervening rock consists of a hard clay slate, whose strata run at a slight angle of declension from west to east, consequently in a direction exactly opposed to that of the stream; but whether nature has formed this passage for the river, or the waters have excavated it beneath the strata of the rock, there is nothing to indicate.

This phenomenon was never mentioned by any traveller, until the spot was visited in 1828 by Mr. Schult, a student of mineralogy of the University of Christiania.

* See plate 3, where all these changes are developed.

DESCRIPTION OF THE UNIVERSITY OF LONDON.

THE University is situated on the East-side of Gower Street, Bedford Square, on a plot of freehold ground, of rather more than seven acres, purchased by the Council for £30,000. The first stone of this noble pile was laid by H. R. H. The Duke of Sussex, on Tuesday, the 30th. of April, 1827; on Tuesday, the 30th. of September, 1828, was held the first meeting of the Proprietors within its wall: and on the following day, the first lecture was delivered. The foundation stone contained, with the medals and coins, a copper-plate bearing the following inscription;

The building when completed is to consist of a centre with two wings, advancing at right angles from each extremity, as in the above sketch of the front elevation. The central being the only part completed, to it the present description is confined. A broad paved footpath on each side of the porter's lodges, and a carriage way between them, lead to the doors in the centre of each of what may be called, for convenience of description, the North and South Ranges; being portions of the building on the North and South sides of the portico. The grand entrance will be up a flight of steps in the centre of the building, on the topmost of which stands a remarkably handsome portico of twelve Corinthian columns; ten in front, and one on each flank. The proportions of the order are taken from the Choragic Monument of Lysicrates at Athens, commonly called the Lantern of Demosthenes, excepting the enrichments of the capital, which are similar to those of the Arch of Trajan. This portico is generally pronounced to be the longest in extent, and the most beautiful in England; the broad steps forming the base, the huge pedestals, on which are to be placed several colossal statues, the great elevation of the portico itself, and the majestic dome rising and receding above, complete the pyramid, and render the whole at once graceful and dignified. If this part of the building be not perfect, it is nearly so;-its only faults, (if faults they are) being, that the base of the dome might have been more elevated, and that the great height and enrichment of the Portico, throw the ranges of the building on each side of it, too much into the shade; but these defects will become less visible, when the wings, which will give greater dignity to the character of the centre, are completed.

The North and South ranges each contain on the upper story, a row of eleven windows, separated by pillasters or antæ, of the same order as the portico; and in the ground floor, the entrance doors are below the 6th. and 11th. windows from the portico of the upper story.

Upon entering the centre door of the North range, there are rooms on each side of the passage, numbered 3 and 4. These are each 46 feet, by 24, and 15 feet high, with four windows in each, and are used as lecture rooms, having six rows of seats rising nine inches above each other, with a back and book-board to all the rows except the first, as in the other lecture rooms. Between the second and third windows in these rooms, are placed the Professor's table and chair. A patent stove delivers warm air into the rooms, and also into the Museum of Natural History above. The passage between these rooms leads into a paved cloister, (No. 5,) 107 feet by 23, and 15 feet high appropriated for the exercise of the students, in the intervals between their lectures. This Cloister looks over the area of the basement story into the North Yard or Court, from which, up a flight of steps on the North side, is the Students' entrance to the two Northern