repetition of this action, it gradually tumbles forward until it regains the water. Its method of sailing is still more curious. Having attained the surface of the water, by means unknown to us, it opens the shell, and puts one half above water, the other with the body of the animal in it remaining below. Great numbers of them are thus frequently seen sailing in company, with their shells sticking up above water, when the weather is fine, and the wind acting upon them as sails; but on the least alarm they instantly shut their shells, and all sink to the bottom together.

The oyster has generally been supposed one of the most sluggish animals in nature, and totally incapable of voluntary motion; but, from the researches of the Abbe Dicquemarre, this opinion seems to be erroneous. The oyster, like many other bivalved shell fish, has a power of squirting water out from its body; and this property may easily be observed by putting some of them into a plate with as much sea water as will cover them. The water is ejected with so much force as not only to repel the approach of ordinary enemies, but to move the whole animal backwards or sideways in a direction contrary to that in which the water was ejected. It has been also supposed that oysters are destitute of sensation; but M. Dicquemarre has shown, that they not only possess sensation, but that they are capable of deriving knowledge from experience. When removed from such places as are entirely covered with the sea, when destitute of experience, they open their shells and die in a few days; but if they happen to escape this danger, and the water covers them again, they will not open their shells again, but keep them shut, as if warned by experience to avoid a danger similar to what they formerly underwent.

though we cannot know the reason of its employing such an extraordinary method. Another remarkable instance is given by Mr. Smellie in the mason bee.

MOTTO. A word or short sentence, put to an emblem or device, or to a coat of arms in a scroll, at the bottom of the escutcheon.

MOULDINESS. A term applied to an ap pearance in bodies which are much exposed to the humidity of the atmosphere, and which shows itself by a kind of white down, or lanugo, on their surface. It is liable to affect different articles of farm produce, unless guarded against by depositing them in proper dry places.

This mouldiness, when viewed with a microscope, affords a curious spectacle; being a kind of meadow, out of which arise herbs and flowers; some only in the bud, others full blown, and others decayed; each having its little root, stalk, and other parts: the figure of which may be seen in Hook's Micrographia. The same may be observed of the mouldiness which gathers on the surface of liquid bodies.

Mr. Bradley observed this mouldiness in a melon very accurately, and found the vegetation of these little plants to be exceedingly quick. Each plant had its seeds in great abundance, which did not seem to be three hours before they began to shoot up; and in six hours more the new plant was complete and mature, and the seed ready to fall. When the fruit had been covered with a mould for six days, its vegetative quality began to abate, and it was entirely gone in two days more; then came on a putrefaction, and the fleshy part of the melon yielding nothing but a stinking water, which began to have a gentle motion on its surface; and in two days' time maggots appeared, which in six more laid themselves up in their bags, where they continued four days, and then came out flies. These maggots were owing to the eggs of flies deposited in the putrefaction.

MOULTING. Among Farmers, a term signifying the changing of the feathers in animals of the domestic bird kind. It is a process which takes place annually towards the latter end of the year, when care should be taken to have them well fed, and kept as much as possible in a sheltered situation. In some sorts of birds, as the goose, advantage is taken of this season for collecting the feathers for various useful purposes.

The motions of the sea urchin are perhaps more curious and complicated than those of any other animal. It inhabits a beautiful multivalved shell, divided into triangular compartments, and covered with great numbers of prickles; from which last circumstance it receives the name of sea urchin, or sea hedgehog. The triangles are separated from one another by regular belts, perforated by a great number of holes, from every one of which issues a fleshy horn similar to that of a snail, and capable of moving in a similar manner. The principal use of these horns seems to be to fix the animal to rocks or stones, though it likewise makes use of them in progressive motion. By means of these horns and prickles it is enabled to walk, either on its back or its belly; but it most commonly makes use of those which are near the mouth. Occasionally it has a progressive motion by turning round like a wheel. Thus,' says Mr. Smellie, in his Philosophy of Natural History, 'the sea urchin furnishes an example of an animal employing many thousand limbs in its various movements. The reader may try to conceive the num-dressing of them. ber of muscles, fibres, and other apparatus which are requisite to the progressive motion of this little animal.' Some animals move backwards, apparently with the same facility that they do forwards, and that by means of the same instruments which move them forward. The common house fly exhibits an instance of this; and frequently employs this retrograde motion in its ordinary courses;

Moulting, in Horses: a term sometimes applied to horses, when they alter, change, or cast their coats towards the latter end of antumn. As they become weak at this period, they should be well kept, and not have too much work. Great care should, likewise, be taken in the cleaning and

MOUNTAIN ASH. An ornamental tree, which in its leaf resembles the common ash; but it bears a clustered flower, that is succeeded by a beautiful red berry.

MOUNTAINS. In those countries which consist only of plains, the smallest elevations are apt

The altitudes of the highest mountains in the above list, were taken under circumstances unfavorable to accuracy; but even with the best instruments, and under the most favorable circumstances, the determination of minute vertical angles, is, from the influence of horizontal refraction, liable to much uncertainty. The process of accurate observation, has uniformly reduced the estimated heights of mountains; and, it is probable, that the Himmaleh and the mountains of Thibet, will be found to have a less altitude than that now given them.

Though mountains appear to us of such an enormous height, when viewed independently of the globe of which they are a part; yet the most elevated of them must appear only as slight rugosities, when their proportion to the diameter of the earth is considered-for the highest mountains known, would be only as a protuberance of a line on the surface of a globe of about twenty-one feet in diameter.

ocean, than on the eastern.
notice a few exceptions to this rule in particular
cases, which might have been named.

Forester and Pallas account for the existence of unequal declivities on the opposite north and south sides, by imagining, that a great flood from the southward has given the earth its present form; Mr. Kirwan, on the other hand, has endeavored to explain the origin of the inequalities, not only of the northern and southern, but also of the eastern and western declivities, by assuming a twofold violent motion of the waters, by which the earth was originally covered, namely, the one from east to west, the other from north to south; the former of these having been resisted by the mountains which stretch from north to south; this opposition must have diminished the impulse of the water, and disposed it to suffer the earthy particles, with which it was impregnated, to be deposited on the eastern declivities, which rendered them gentle, gradual, and moderate; while the western sides, The circumstance of one side of a chain of receiving no such accession from depositions, must mountains, being in general steeper than the other, have remained steep and craggy. The course of has given origin to an instructive paper by Mr. the waters, from north to south, was in the same Kirwan, 'On the Declivities of Mountains.' That manner resisted by the primeval mountains that one part of almost every high mountain is steeper run from east to west, which occasioned similar than another, could not have escaped the notice depositions on the northern sides of these mounof any person who had traversed such mountains; tains, against which these waters impinged, and but that nature, in the formation of such declivities, thus smoothed them. Again, where mountains had any regard to different aspects or points of intersect each other in an oblique direction, the the compass, seems to have been first remarked northeast side of one range being contiguous to the by the celebrated Swedish geologist, Mr. Tilas, in southwest flanks of another range, there the afflux the 22d volume of the Memoirs of Stockholm, for of adventitious particles on the northeast side of 1760. Neither Vereneus, Ludolph, nor Buffon, in the one, must have frequently extended to the his Natural History, published in 1748, have no- southwest side of the other; particularly if that ticed this remarkable circumstance. The discovery, afflux were strong and copious: thus the Ertzgethat the different declivities of the flanks of moun-berg of Saxony, which runs from west to east, has tains, bear an invariable relation to their different its northeast side contiguous to the southwest side aspects, seems to have been first published by of the Riesengebirge, which separates Silisia from Bergmann, in his Physical Description of the Bohemia, and hence these latter are covered with Earth, of which the second edition appeared in the same of gneiss, &c. as the northern sides of the 1773. He there remarked, that in mountains that Saxon, and thereby are rendered smooth and genextend from north to south, the western flank is the tle, compared with the opposite side, which being steepest; and that in mountains which run east sheltered, remains steep and abrupt. He also adand west, the southern declivity is the steepest, mits, that from various contingent local causes, and the northern the gentlest. This assertion he such as partial inundation, earthquakes, volcanoes, grounds on the observation related in his first vol- the erosion of rivers, the elapsion of strata, disinume, namely, that in Scandinavia, the Svevoberg tegration, the disruption of the lofty mounds, by mountains that run north and south, separating which many lakes were anciently hemmed in, Sweden from Norway, the western or Norwegian several changes were produced in particular counsides are the steepest, and eastern or Swedish the tries, that may, at first sight, appear exceptions to most moderate; the verticality or steepness of the the operations of the general causes stated by him. former being to that of the latter as forty or fifty to Thus the mountains of Kamtschatka had their four or two: that the Alps are steeper on the eastern flanks torn and rendered abrupt by the irwestern and southern sides, than on the eastern ruption of the general deluge, probably accompaniand northern: in America, the Cordilleras are ed by earthquakes; and thus Meissner had its north steeper on the western side, which faces the Pacific and east flanks undermined by the river Warra.

The following beautiful description, is from a journal of an excursion upon the Andes; made under the direction of the king of Spain, by Ulloa. After,' says he, having travelled for upwards of three days through boggy roads, in which the mules at every step sunk up to their bellies, we began at length to perceive an alteration in the climate; and having been long accustomed to heat, we now began to feel it grow sensibly colder. At Fariguagua we often see instances of the effects of two opposite temperatures, in two persons happening to meet; one of them leaving the plains below, and the other descending from the mountain. The former thinks the cold so severe, that he wraps himself up in all the garments he can procure; while the latter finds the heat so great, that he is scarcely able to bear any clothes whatever. The one thinks the water so cold, that he avoids being sprinkled by it; the other is so delighted by its warmth, that he uses it as a bath. This difference only proceeds from the change naturally felt at leaving a climate, to which one has been accustomed, and coming into another of an opposite temperature.

'The ruggedness of the road is not easily described. In some parts, the declivity is so great, that the mules can scarcely keep their footing; and in others the acclivity is equally difficult. There are some places where the road is so steep, and yet so narrow, that the mules are obliged to slide down, without making the least use of their feet. On one side of the rider, in this situation, rises an eminence of several hundred yards, and on the other, an abyss of equal depth; so that if he in the least checks his mule, they must both unavoidably perish.

from the intenseness of the cold, and violence of the storms. The sky around was in general involved in thick fogs, which, when they cleared away, and the clouds by their gravity moved nearer to the surface of the earth, appeared surrounding the foot of the mountain, at a vast distance below, like a sea encompassing an island in the midst of it. When this happened, the horrid noises of the tempests were heard from beneath, discharging themselves on Quito and the neighboring country. I saw lightnings issue from the clouds, and heard the thunders roll far beneath me. All this time, while the tempest was raging below, the mountain top, where I was placed, enjoyed a delightful serenity; the wind was abated, the sky clear, and the rays of the sun moderated the severity of the cold. However, this was of no long duration, for the wind returned with all its violence; whilst my fears were increased by the dreadful concussions of the precipice, and the fall of enormous rocks, the only sound that was heard in this dreadful situation.'

MOURNING. A particular dress or habit, worn to signify grief, on some melancholy occasion. The modes of mourning are various in various countries; as also are the colors that obtain for that end. In Europe and America, the ordinary color for mourning is black; in China, it is white; in Turkey, blue or violet; in Egypt, yellow; in Ethiopia, brown. The ancient Spartan and Roman ladies mourned in white; and the same color obtained formerly in Castile, on the death of their princes. Herrera observes, that the last time it was used was in 1498, at the death of prince John. Kings and cardinals always mourn in purple.

Mourning, among the ancients, was expressed various ways, as by tearing their clothes, by wearing sackcloth, laying aside crowns and every other mark of joy. Plutarch, in his Life of Cato, relates, that from the time of his leaving the city with Pompey, he neither shaved his head, nor, as usual, wore the crown or garland. Sometimes public grief was testified by a general fast.

‘After having travelled nine days, in this manner, Each people pretend to have their reasons for slowly winding along the side of a mountain, we the particular color of their mourning: white is began to find the whole country covered with a supposed to denote purity; yellow, that death is hoar frost. At length, after a journey of fifteen the end of human hopes, as leaves when they fall, days, we arrived upon a plain, on the extremity of and flowers when they fade, become yellow; which, stands the city of Quito, the capital of one brown denotes the earth, whither the dead return; of the most charming regions upon earth. Here, black, the privation of life, as being the privation in the centre of the torrid zone, the heat is not of light; blue expresses the happiness which it is only very tolerable, but in some places the cold hoped the deceased enjoy; and purple or violet, also is painful. Here they enjoy all the tempera-sorrow on the one side, and hope on the other, as ture and advantages of perpetual spring; their being a mixture of black and blue. fields being always covered with verdure, and enamelled with flowers of the most lively colors. However, although this beautiful region be so immensely high, and, although it took so many days of painful journey in the ascent, it is still overlooked by tremendous mountains; their sides covered with snow, and yet flaming with volcanoes at the top. These seem piled one upon the other, and rise to a most astonishing height, with great coldness. However, at a determined point above the surface of the sea, the congelation is found at the same height, in all the mountains. Those parts, which are not subject to a continual frost, have growing upon them a sort of rush, very soft and flexible. Higher up, the earth is entirely bare of vegetation, and seems covered with eternal snow. The most remarkable mountains are the Cotopaxi, Chimborazo, and Pitchinca. The first is more than three geographical miles above the surface of the sea; the rest are not much inferior. On the top of the latter, I suffered particular hardships,

Among the Romans a year of mourning was ordained, by law, for women who lost their husbands.

In public mournings at Rome, the shops were shut up, the women laid aside all their ornaments, the senators their latiolavian robes, and the consuls sat in a lower seat than usual.

The ancients had a remarkable way of mourning for soldiers slain in battle. The whole army attended the funeral solemnities, with their arms reversed, it being customary for mourners, in most of their actions, to behave themselves in a manner contrary to what was usual at other times. In

those places where it was the fashion to wear long hair, mourners were shaved; and where others shaved, mourners wore long hair. The conjectures of those, therefore, is frivolous, who imagine that the soldiers turned the heads of their shields downwards, lest the gods, whose images were en-ed with organs which perform those processes. graved upon them, should be polluted with the sight of a corpse; since not the gods only, but any other figures, were frequently represented on shields; nor did the few only near the corpse, but the whole company held their shields in the same position: not to mention that other arms were also pointed downwards.