The escarpment of ice was 35 to 40 toises high; and, according to the report of the Tungusians, the animal was, when they first saw it, seven toises below the surface of the ice, &c.

'On arriving with the Mammoth at Borchaya, our first care was to separate the remaining flesh and ligaments from the bones, which were then packed up. When I arrived at Jakutsk, I had the good fortune to re-purchase the tusks, and from thence expedited the whole to St. Petersburg.'

The skeleton is now put up in the museum of the academy, and the skin still remains attached to the head and the feet.

The Mammoth is described by M. Cuvier as a different species from either of the two elephants living at the present day, the African or the Indian. It is distinguished from them by the teeth, and by the size of the tusks, which are from ten to fifteen feet long, much curved, and have a spiral turn outwards. The alveoli of the tusks are also larger, and are produced farther. The neck is shorter, the spinal processes larger, all the bones of the skeleton are stronger, and the scabrous surfaces for the insertion of the muscles more prominent than in the other species. The skin being covered with thick hair, induces M. Cuvier to consider that it was the inhabitant of a cold region. The form of the head is also different from that of the living species, as well as the arrangement of the lines of the enamel of the teeth: but for these and other particulars, see the Memoirs of M. Cuvier in the Annales du Muséum d'Histoire Naturelle.

The Mammoth more nearly resembles the Indian than the African species of elephant.

A part of the skin and some of the hair of this animal was sent by Mr. Adams to Sir Joseph Banks, who presented them to the Museum of the Royal College of Surgeons. The hair is entirely separated from the skin, excepting in one very small part, where it still remains firmly attached. It consists of two sorts, common hair and bristles, and of each there are several

varieties, differing in length and thickness. That remaining fixed on the skin is of the colour of the camel, an inch and an half long, very thick set, and curled in locks. It is interspersed with a few bristles, about three inches long, of a dark reddish colour.

Among the separate parcels of hair are some rather redder than the short hair just mentioned, about four inches long, and some bristles nearly black, much thicker than horse-hair, and from 12 to 18 inches long.

The skin when first brought to the museum was offensive. It is now quite dry and hard, and where most compact is half an inch thick. Its colour is the dull black of the living elephants.

ART. VIII. On the Figure of the Earth. By M. de Laplace.

THE multiplied experiments made with the pendulum have shewn that the increase of gravity follows a very regular progression, and that it is very nearly as the square of the sine of the latitude. This force being the result of the attractions of all the terrestrial molecules, observations of it, compared with the theory of the attraction of spheroids, offer the only means which can enable us to penetrate into the internal constitution of the earth. The result is, that this planet is formed of strata, of which the density increases from the surface to the centre, and which are arranged regularly round that point. I have published, at the end of the Connaissances des Tems for 1821, the following Theorem, which I have demonstrated in the second volume of the Nouveaux Mémoires de l'Académie des Sciences.

"If the length of the seconds pendulum at the equator be taken as unity, and if to the length of this pendulum, observed at any point on the surface of the terrestrial spheroid, be added, half the height of this point above the level of the ocean, divided by half the polar axis, a height which is given by barometrical observation, the increase of this length, thus corrected, will be, on the hypothesis of a constant density below a small depth,

equal to the product of the square of the sine of the latitude by five fourths of the ratio of the centrifugal force to the gravity at the equator, or by 43 ten-thousandths."

This theorem is generally true, whatever may be the density of the sea, and the manner in which it covers the earth.

Experiments with the pendulum made in the two hemispheres, agree in giving to the square of the sine of the latitude, a coefficient somewhat larger, and nearly equal to 54 ten-thousandths. It is therefore well proved by these experiments that the earth is not homogeneous in the interior, and that the density of the strata increases from the circumference to the centre.

But the earth, though heterogeneous in a mathematical sense, may still be chemically homogeneous, if the increase of density of its strata is caused only by the additional pressure they suffer as they approach towards the centre. It is easy to conceive that the immense weight of the superior strata may considerably increase their density, though they may not be fluid; for it is known that solid bodies are compressed by their own weight. The law of the densities which result from these compressions being unknown, we cannot tell how far the density of the terrestrial strata may be thus increased. The pressure and the heat which we can produce are very small, compared to those which exist at the surface, and in the interior of the sun and stars. It is even impossible for us to have an idea of the effect of these forces, united in those immense bodies. Every thing tends to make us believe that they have existed at one time in a high degree on the earth, and that the phenomena which they have occasioned, modified by their successive diminution, form the present state of the surface of our globe; a state which is nothing more than the element of a curve, of which time is the abscissa, and of which the ordinates will represent the changes that this surface has suffered without ceasing. We are far from knowing the nature of this curve, and we cannot therefore ascend with certainty to the origin of what we observe on the earth; and if, to satisfy the imagination, always troubled by ignorance of the cause of the phenomena which interest us, a few conjectures are ventured, it is wise not to offer them except with extreme caution

The density of a gas is proportional to its compression, when the temperature remains the same. This law which is found true within those limits of density, where we have been able to prove it, evidently cannot apply to liquids and solids, of which the density is very great, compared to that of gas, when the pressure is very small, or even nothing. It is natural to suppose that these bodies resist compression the more they are compressed; so that the ratio of the differential of the pressure to that of the density, instead of being constant, as with gases, increases with the density. The most simple function which can represent the ratio, is the first power of the density, multiplied by a constant quantity. It is this which I have adopted, because it unites to the advantage of representing in the simplest manner what we know of the compression of liquids and solids, a facility of calculation in researches on the figure of the earth. Until now, mathematicians have not included in this research the effect resulting from the compression of the strata. Dr. Young has called their attention to this object, by the ingenious remark, which may be thus stated, the increase of density of the strata of the terrestrial spheroid. I have supposed that some interest may be excited by the following analysis, from which it appears that it is possible to explain all the known phenomena depending on the law of the density of these strata. These phenomena are the variation of the degrees of the meridian, and of gravity, the precession of the equinoxes, the nutation of the terrestrial axis, the inequalities which the flattening of the earth produces in the motion of the moon, and lastly, the ratio of the mean density of the earth to that of water, which Cavendish has fixed by an admirable experiment at five and a half. In proceeding from the law already announced of the compression of liquids and solids, I find that, if the earth be supposed to be formed of a substance chemically homogeneous, of which the density is 24 that of common water, and which compressed by a vertical column of its own substance, equal to the millionth part of half the polar axis, will augment in density 5.5345 millionths of its first density, it will account for all the phenomena. The existence of such a body is very admissible, and there are apparently such on the surface of the earth.

sup

If the earth were entirely formed of water, and if it be posed in conformity with the experiments of Canton, that the density of water, at the temperature of ten degrees (50°. Fahr.) and compressed by a column of water 10 metres (32.81925 ft.) in height increases by 44 millionths, the flattening of the earth would be ; the coefficient of the square of the sine of the latitude in the expression of the length of the second's pendulum would be 59 ten-thousandths, and the mean density of the earth would be nine times that of water. These results differ from observations by more than the errors to which they are liable.

I have supposed the temperature uniform throughout the whole extent of the terrestrial spheroid; but it is very possible that the heat is greater towards the centre, and that would be the case if the earth, originally highly heated, were continually cooling. The ignorance in which we are with respect to the internal constitution of this planet, prevents us from calculating the law by which the heat decreases, and the resulting diminution in the mean temperature of climates; but we can prove that this diminution is insensible for the last 2,000 years.

Suppose a space of a constant temperature, containing a sphere having a rotatory motion; and, suppose that after a long time. the temperature of the space diminishes one degree; the sphere will finally take this new temperature; its mass will not be at all altered, but its dimensions will diminish by a quantity which I will suppose to be a hundred thousandth, a diminution which is nearly that of glass. In consequence of the principle of areas, the sum of the areas which each molecule of the sphere will describe round its axis of rotation will be the same in a given time, as before. It is easy to conclude from this, that the angular velocity of rotation will be augmented by a fifty thousandth. So that, supposing the time of a rotation to be one day, or a hundred thousand decimal seconds, it will be diminished two seconds by the diminution of a degree in the temperature of the space. If we extend this consequence to the earth, and also consider that the duration of the day has not varied since the time of Hipparchus, by the hundredth of a second, as I have shewn by the comparison of observations with the