OSCILLATION. The motion of a propelled | the top of the head to the ground, but from the body, as a pendulum, when restrained at right an- | back it is only four; so that the head and neck are gles to the direction of force; the body, in conse- above three feet long. Some reach the height of quence, ascends in a curve, and descending by its nine feet. From the top of the head to the rump, own accelerated weight, rises again on the opposite when the neck is stretched out in a right line, it is side, continuing this oscillation till the friction of six feet long, and the tail is about a foot more. the centre and the air have taken away, or received One of the wings, without the feathers, is a foot the original force. The time is the same in the and a half; and being stretched out, with the same pendulum, whatever be the length of the feathers, is three feet. oscillation, but in pendulums of different lengths the time is as the square root of the length; thus, a pendulum of thirty-six inches vibrates but a sixth of the time of one of six inches.

The plumage is much alike in all; that is, generally black and white; though some of them are said to be gray. The greatest feathers are at the extremities of the wings and tail, and the largest are generally white. The next row is black and OSTRACISM. A judgment of the assembly white: and of the small feathers on the back and of the people in Athens, which checked the influ- belly, some are white and others black. There ence of powerful citizens by an exile of ten years. are no feathers on the sides, nor yet on the thighs, If any person was regarded as obnoxious, every nor under the wings. The lower part of the neck, citizen who was of this opinion wrote the name about half way, is covered with still smaller feathof the person to be banished on a shell, (ostrakon) ers than those on the belly and back; and those, which he deposited in the place appointed in the like the former, also are of different colors. The forum. This place was enclosed by wooden bal-head and upper part of the neck are covered with ustrades, and had ten gates, at which the ten tribes hair. of Athens entered at the assemblies of the people. The archons counted the shells deposited by the citizens, and if at least 6000 were in favor of the banishment of the accused, the banishment took effect; otherwise, he was acquitted.

At the end of each wing there is a kind of spur, almost like the quill of a porcupine. It is an inch long, being hollow, and of a horny substance. There are two of these on each wing; the largest of which is at the extremity of the bone of the wing, and the other a foot lower. The neck seems to be more slender in proportion to that of other birds, from its not being furnished with feathers.

Persons were exiled by the ostracism for ten years, and, after the expiration of this period, the exiled citizen was at liberty to return to his country, and take possession of his wealth, and all his civil privileges. To this sentence no disgrace was The thighs are very fleshy and large, being covattached; for it was never inflicted upon criminals, ered with a white skin, inclining to redness, and but only upon those who had excited the jealousy wrinkled in the manner of a net, whose meshes or suspicion of their fellow citizens, by the in-will admit the end of a finger. Some have very fluence which they had gained by peculiar merit, wealth or other causes. Aristotle and Plutarch called the ostracism the medicine of the state. Still it was often used by bad and envious men to accomplish their unlawful designs, and to destroy the influence of patriotic citizens.

small feathers here and there on the thighs; and others again have neither feathers nor wrinkles. The legs are covered before with scales. The end of the foot is cloven, and has two very large toes, which, like the leg, are covered with scales. These toes are of equal sizes. The largest, which is on the inside, is seven inches long, including the OSTRICH. The ostrich is a bird very ancient-claw, which is near three fourths of an inch in ly known, since it is mentioned in the oldest of books. It has furnished the sacred writers with some of their most beautiful imagery; and its flesh was, even previous to the days of Moses, apparently a common species of food, since we find it interdicted, among other unclean animals, by the Jewish legislator.

The ostrich is generally considered as the largest of birds, but its size serves to deprive it of the principal excellence of this class of animals, the power of flying. The medium weight of this bird inay be estimated at seventy-five or eighty pounds, a weight which would require an immense power of wing to elevate into the atmosphere; and hence all those of the feathered kind which approach to the size of the ostrich, such as the touyou, the cassowary, the dodo, neither possess, nor can possess, the faculty of flight. The head and bill of the ostrich somewhat resemble those of a duck; and the neck may be compared to that of a swan, but that it is much longer; the legs and thighs resemble those of a hen; though the whole appearance at a distance bears a strong resemblance to that of a camel it is usually seven feet high from

length, and almost as broad. The other toe is but four inches long, and is without a claw.

The ostrich is a native only of the torrid regions of Africa and Arabia, and has never bred out of those countries which first produced it. Though, however, the climate of France be much less warm than that of Barbary, yet some ostriches have been known to lay in the royal menagerie at Versailles; but the gentlemen of the Academy have in vain attempted to make these eggs produce by an artificial process. This bird, so disqualified for society with man, inhabits from preference, the most solitary and horrid deserts, where there are few vegetables to clothe the surface of the earth, and where the rain never comes to refresh it. The Arabians assert that the ostrich never drinks; and the place of its habitation seems to confirm the assertion. In these formidable regions ostriches are seen in large flocks, which to the distant spectator appear like a regiment of cavalry, and have often alarmed a whole caravan. There is no desert, how barren soever, but is capable of supplying these animals with provisions: they eat almost every thing; and these barren tracts are thus

doubly grateful as they afford both food and secur-tury, was frequently carried by large ostriches. ity. In southern Africa they are exceedingly in- Moore, an English traveller, relates, that he had jurious to the farmers, as they will destroy a field seen at Joar, in Africa, a man travelling on an osof wheat so effectually as not to leave a single ear trich. And Vallisnieri speaks of a young man, behind; and this operation they perform without who exhibited himself upon one of these birds at danger to themselves, as they are so vigilant and so Venice. In fine, M. Adanson saw, at the factory swift, that it is almost impossible to get a shot at at Podor, two ostriches, which were yet young, them. The ostrich is of all animals the most vo- of which the stronger went at a pace which would racious. It will devour leather, grass, hair, iron, have distanced the fleetest English race horse, stones, or any thing that is given. Nor are its with two negroes on its back. Whether this bird powers of digestion less in such things as are could be broken and tamed so as to carry its rider digestible. Those substances which the coats of with the same safety and docility as a horse, is the stomach cannot soften pass whole; so that a different question; and let it be remembered glass, stones, or iron, are excluded in the form in that, though the ostriches above mentioned ran which they are devoured. All metals, indeed, for a short time faster than a race horse, there is which are swallowed by any animal, lose a part no reason to believe that they could hold out so of their weight, and often the extremities of their long. figure, from the action of the juices of the stomach upon their surface. A quarter pistole which was swallowed by a duck, lost seven grains of its weight in the gizzard before it was voided; and it is probable that a still greater diminution of weight would happen in the stomach of an ostrich. Considered in this light, therefore, this animal may be said to digest iron; but such substances seldom remain long enough in the stomach of any animal to undergo so tedious a dissolution. The ostrich lays very large eggs, some of them being above five inches in diameter, and weighing above fifteen pounds. These eggs have a very large shell, somewhat resembling those of the crocodile, except that those of the latter are less and rounder. It is a curious fact that these eggs often contain a number of small, exceedingly hard, oval shaped pebbles, about the size of a marrowfat pea, and of a yellow color. They are sometimes set, and used

as buttons.

From ancient writers we learn, that whole nations have acquired the name of Strathophagi, (ostrich eaters) from the preference which they had manifested for the flesh of this bird. Apicius has recommended a peculiar sauce for the ostrich, which shows at least that it was eaten among the Romans, and at a single feast the Emperor Heliogabalus was served with the brains of six hundred of these animals. Even at this period some of the savage nations of Africa hunt them not only for their plumage, but for their flesh also, which they consider as a dainty. They sometimes also breed these birds tame, to eat the young ones, of which the female is said to be the greatest delicacy; and a single egg is said to be a sufficient entertainment for eight men. The skin of the ostrich is so thick, that it is used for leather by the Arabians; and of the eggs drinking cups are made. The value of the plumage is well known in most countries of Europe.

The season for laying depends on the climate; As the spoils of the ostrich are thus valuable, it in the northern parts of Africa it is about the be- is not to be wondered at that man has become ginning of July; in the south it is about the latter their most assiduous pursuer. For this purpose end of December. These birds are very prolific, the Arabians train up their best and fleetest horses, and lay generally from thirty to forty eggs in a and hunt the ostrich still in view. Perhaps of all season, and about twelve at one clutch. It has varieties of the chase, this, though the most laborbeen commonly reported that the female deposits ious, is yet the most entertaining. As soon as the them in the sand; and, covering them up, leaves hunter comes within sight of his prey, he puts on them to be hatched by the heat of the climate, and his horse with a gentle gallop, so as to keep the then permits the young to shift for themselves. ostrich still in sight; yet not so as to terrify him Very little of this, however, is true: no bird has a from the plains into the mountains. Upon obstronger affection for her young than the ostrich, serving himself, therefore, pursued at a distance, and none watches her eggs with greater assiduity. the bird begins to run at first, but gently; either It happens, indeed, in those hot climates, that there insensible of his danger, or sure of escaping. In is less necessity for the continual incubation of the this situation he somewhat resembles a man at full female; and she more frequently leaves her eggs, speed, his wings, like two arms, keep working with which are in no fear of being chilled by the a motion correspondent to that of his legs; and weather: but though she sometimes forsakes them his speed would very soon snatch him from the by day, she always carefully broods over them by view of his pursuers; but, unfortunately for the night; nor is it more true that they forsake their silly creature, instead of going off in a direct line, young after they are excluded the shell. On the he takes his course in circles: while the bunters contrary, the young ones are not even able to walk still make a small course within, relieve each other, for several days after they are hatched. During meet him at unexpected turns, and keep him thus this time the old ones are very assiduous in supply- still employed, still followed, for two or three days ing them with grass, and very careful to defend together. At last, spent with fatigue and famine, them from danger: nay, they encounter every and finding all power of escape impossible, he en danger in their defence. deavors to hide himself from those enemies he The strength and size of the ostrich has sug- cannot avoid, and covers his head in the sand, or gested to men the experiment of using them as the first thicket he meets. Sometimes, however, animals of burden. The tyrant Firmius, who he attempts to face his pursuers; and, though in reigned in Egypt about the end of the third cen- general the most gentle animal in nature, when

driven to desperation, he defends himself with his beak, his wings, and his feet. Such is the force of his motion that a man would be utterly unable to withstand him in the shock.

The Strathophagi had another mode of capturing these animals. They disguised themselves in the skin of an ostrich, and putting one of their arms through the neck, they imitated all its motions. By this means they are said to have enabled themselves to approach and take them at pleasure. In the same manner the savages of America disguise themselves as a roebuck, in order to surprise that animal.

Ostriches are sometimes bred in flocks, for they are easily tamed. In this domesticated state they play and frisk about with much vivacity, and are tractable and familiar towards those who are acquainted with them. To strangers, however, they are often fierce, and will attack them with fury, making an angry hissing noise, and having their throats inflated, and their mouths open. During the night they frequently utter a discordant cry, which bears a resemblance to the distant roaring of a lion, or the hoarse tone of a bear or an ox when in great agony.

OSURIUM. A new metal lately discovered by Mr. Tenant among platina, and thus called by him from the pungent and peculiar smell of its oxide. Pure metal, previously heated, did not appear to be acted upon by acids. Heated in a silver cup with caustic alkali, it combined with it, and gave a yellow solution similar to that from which it was procured. From this solution acids separate the oxide of osurium.

but it is in the Hudson's Bay possessions that these animals are obtained in the greatest abundance, and supply the traders with the largest number of their valuable skins. Seventeen thousand and three hundred otter skins have been sent to England in one year by the Hudson's Bay company.

Nature appears to have intended the otter for one among her efficient checks upon the increase of the finny tribes, and every peculiarity in its conformation seems to have this great object in view. The length of body, short and flat head, abbreviated ears, dense and close fur, flattened tail, and disproportionately short legs with webbed feet, all conspire to facilitate the otter's movements through the water. In the crystal depths of the river, few fish can elude this swiftly moving and destructive animal, which unites to the qualities enabling him to swim with fish-like celerity and ease, the peculiar sagaciousness of a class of beings far superior in the intellectual scale to the proper tenants of the flood. In vain does the pike scud before his pursuer, and spring into the air in eagerness to escape; or the trout part with the velocity of thought from shelter; in vain does the strong and supple eel seek the protection of the shelving bank or the tangled ooze in the bed of the stream; the otter supplies by perseverance what may be wanting in swiftness, and by cunning where he is deficient in strength, and his affrighted victims, though they may for a short time delay, cannot avert their fate. When once his prey is seized, a single effort of his powerful jaws is sufficient to render its struggles unavailing; one crush with his teeth breaks the spine of the fish behind the dorsal fin, and deprives it of the ability to direct its motions, even if it still retain the least power to move.

OTTAR OF ROSES. An aromatic oil, obtained from the flowers of the rose, but in such The residence of the otter is a burrow or excasmall quantities that half an ounce can hardly be vation in the bank of a river or stream, and the enprocured from a hundred pounds of the petals. trance to this retreat is under water; at some disThis oil is solid and white at the common teinper-tance from the river an airhole is generally to be ature of the atmosphere, but on the application of found opening in the midst of a bush or other heat, becomes fluid, and assumes a yellow color. place of concealment. The burrow is frequently It is brought in considerable quantities from Tur- to be traced for a considerable distance, and in nukey, and is sold at the extravagant price of from merous instances leads to the widely spreading fifteen to twenty dollars an ounce. That from the roots of large trees, underneath which the otter East Indies, where it is said to be chiefly manu- finds a secure and comfortable abode. The winter factured, when genuine, has been sold at a much residence is generally chosen in the vicinity of more exorbitant price. It is frequently adulterated falls or rapids where the water is least liable to be with oil of sandal wood; but the fraud is easily closed from the severity of the cold, and where detected by those who are accustomed to its scent, the otter may find the readiest access to the fish and also by the fluidity. The true ottar of roses upon which his subsistence depends. Otters have is, undoubtedly, the most elegant perfume known. been seen during the coldest parts of winter at very considerable distances from their usual haunts, or any known open water, as well as upon the ice of large lakes, a circumstance that appears the more singular as this animal is not known to kill game on land at this season. When the otter is in the woods where the snow is light and deep, it dives if pursued; and moves with considerable rapidity under the snow. But its route is always betrayed by the rising of the superincumbent mass, and numbers of them are occasionally killed with clubs by the Indians, while thus endeavoring to make their escape. The old otters, however, are often able to disappoint their pursuers by force, if not by address, for they turn upon them with great fury and ferocity, and so desperate are the

OTTER. The American otter is about five feet in length, including the tail, the length of which is eighteen inches. The color of the whole body, except the chin and throat, which are dusky white, is a glossy brown. The fur throughout is

dense and fine.

This otter inhabits South, as well as various parts of North America, along the fresh water streams and lakes, as far north as to the Coppermine river. In the southern, middle and eastern states of the Union, they are comparatively scarce, but in the western states they are in many places still found in considerable numbers. On the tributaries of the Missouri they are very common;

wounds inflicted by their teeth, that few individuals | quarter round. It is usually cut with representaare willing to encounter the severity of their bite. tions of eggs and arrow heads or anchors placed The Indians have various ways of killing the alternately. otter, one of which is that of concealing themselves near the haunts of the animal on moonlight nights and shooting them when they come forth for the purpose of feeding or sporting. A common mode of taking them is by sinking a steel strap near the mouth of their burrow, over which the animal must pass in entering or leaving the den.

OUNCE. A little weight, the sixteenth part of a pound avoirdupoise, and the twelfth part of a pound troy: the ounce avoirdupoise is divided into eight drams, and the ounce troy into twenty pennyweights. The avoirdupoise ounce is less than the troy ounce, but the avoirdupoise pound is We have not alluded to the sporting of the otter, greater than the troy pound. One hundred and and may now remark that its disposition in this seventy-five troy ounces are equal to one hundred respect is singular and interesting. Their favorite and ninety-two avoirdupoise ounces: but one sport is sliding, and for this purpose, in winter, the hundred and forty-four pounds avoirdupoise are highest ridge of snow is selected, to the top of equal to one hundred and seventy-five pounds which the otters scramble, where lying on the bel-troy. Therefore one pound avoirdupoise, is equal ly, with the fore feet bent backwards, they give to one pound, two ounces, eleven penny weights, themselves an impulse with their hind legs, and sixteen grains troy. swiftly glide head foremost down the declivity, sometimes for the distance of twenty yards. This sport they continue apparently with the keenest enjoyment, until fatigue or hunger induces them to desist.

Ac

OU-POEY-TSE. A name given by the Chinese to nests made by certain insects upon the leaves and branches of the tree called yen-fou-tse. These nests are much used in dyeing, and the In the summer this amusement is obtained by physicians employ them for curing many distemselecting a spot where the river bank is sloping, pers. Some of these nests were brought to Euhas a clayey soil, and the water at its base is of a rope, and put into the hands of the celebrated considerable depth. The otters then remove from Geoffrey. After having examined them with the the surface, for the breadth of several feet, the utmost attention, the learned academician thought sticks, roots, stones and other obstructions, and he perceived some conformity in them to those render the surface as level as possible. They excrescences which grow on the leaves of the elin, climb up the bank at a less precipitous spot, aud and which the vulgar call elm-bladders: he found starting from the top, slip with velocity over the these nests so sharp and astringent to the taste, inclining ground, and plump into the water to a that he considered them as far superior to every depth proportioned to their weight and rapidity of other species of galls used by the dyers. motion. After a few slides and plunges the sur-cording to him, they are the strongest astringents face of the clay becomes very smooth and slippery, existing in the vegetable kingdom. It is certain and the rapid succession of the sliders show how that there is a great affinity between the ou-poeymuch these animals are delighted by the game, as tse and the elin-bladders. The form of both is well as how capable they are of performing actions, unequal and irregular; they are covered on the which have no other object than that of pleasure outside with a short down, which renders them or diversion. This amusement is so congenial to soft to the touch: within they are full of a whitish the frolic spirit of boyhood, that in vicinities gray dust, in which may be observed the dried rewhere otter slides are found, youngsters, while mains of small insects, without discovering any bathing, sometimes take possession of one, and aperture through which they might have passed. sitting at the top, glide thence with great glee into These nests or bladders harden as they grow old; the water, in imitation of the sports of the otter. and their substance, which appears resinous, beBut not recollecting that the skin of the otter is comes brittle and transparent; however, the Chiprotected by a thick and fine fur against the effects nese do not consider the ou-poey-tse, notwithof friction, the poor lads find, on relinquishing standing their resemblance to elm-bladders, as extheir play, that, notwithstanding the smoothness crescences of the tree yen-fou-tse, upon which of the slide, the fine sand mingled with the clay they are found. They are persuaded that the inhas robbed them of a broad surface of cuticle, the sects produce a kind of wax, and construct for loss of which experimentally convinces them, be-themselves on the branches and leaves of this tree fore they can limp home, that an otter slide, to the end, is not altogether well suited for the recreation

of human bathers.

6

The difference between this species and the European otter, are thus pointed out by Captain Sabine. The neck of the American otter is elongated, not short, and the head narrow and long in comparison with the short broad visage of the European species; the ears are consequently much closer together than in the latter.'

OVOLO, or OVUM. In Architecture, a round moulding, whose profile or sweep, in the Ionic and Composite capitals, is usually a quadrant of a circle: whence it is often commonly called the

(the sap of which is proper for their nourishment) little retreats, where they may wait for the time of their metamorphosis, or at least deposit in safety their eggs, which compose that fine dust with which the ou-poey-tse are filled. Some of the ou-poey-tse are as large as one's fist; but these are rare, and are generally produced by a worm of extraordinary strength, or which has associated with another, as two silkworms are sometimes seen shut up in the same ball. The smallest oupoey-tse are of the size of a chestnut; the greater part of them are round and oblong; but they seldom resemble one another entirely in their exterior configuration. At first they are of a dark green color, which afterwards changes to yellow; and

the husk, though pretty firm, becomes then very brittle. The Chinese peasants collect these before the first hoar-frosts. They take care to kill the worm enclosed in the husks, by exposing them for some time to the steam of boiling water. Without this precaution, the worm might soon break through its weak prison, which would immediately burst and be useless. They are used at Pekin for giving paper a durable and deep black color: in the provinces of Kiang-nan and Tche-Kiang, where a great deal of beautiful satin is made, they are employed for the dyeing of the silk before it is put on the loom. The Chinese literati also blacken their beards with them when they become white. The medicinal properties of the ou-poey-tse are very numerous. The Chinese physicians introduce them into the composition of many of their remedies.

their game, and to return, in like manner, before the broad daylight begins to dazzle them with its splendor.

Yet the faculty of seeing in the night, or of being entirely dazzled by day, is not alike in every species of these nocturnal birds. The common white or barn owl, for instance, sees with such exquisite acuteness in the dark, and though the barn has been shut at night, and the light thus totally excluded, that it perceives the smallest mouse that peeps from its hole: on the contrary, the brown horned owl is often seen to prowl along the hedges by day, like the sparrowhawk; and sometimes with good success. The note of the owl is not unpleasant. A friend,' says Mr. White, 'remarks that most of his owls hoot in B flat, but that one went almost half a note below A. A neighbor of mine, who is said to have a nice ear, remarks that the owls about this village hoot in three different keys, in G flat, or F sharp, in B flat and A flat. He heard two hooting to each other, the one in A flat, and the other in B flat.'

All this tribe of animals, however they may differ in their size and plumage, agrce in their general characteristics of preying by night; their

claws made for tearing their prey; and their stomachs for digesting it. It must be remarked, however, that the digestion of all birds that live upon mice, lizards or such like food, is not very perfect; for though they swallow them whole, yet they are always seen some time after to disgorge the skin and bones rolled up in a pellet, as being indigestible.

OWL. One of the most striking examples of the prevalence of vulgar prejudice over common sense and daily experience is afforded by the contemptuous antipathy in which the owls, the most useful to man of all the birds of prey, are almost universally held by those who derive the greatest advantage from their peculiar instincts. The sin-bodies are strong and muscular; their feet and gularity of their appearance, the loneliness of their habitations, the moping melancholy of their manners, their nocturnal habits, the still silence of their motion, and the grating harshness of their cries, combine to render them objects of dislike and terror to the timid and superstitious, who see in them something of an unearthly character, and regard them as birds of evil omen. But the most common observation teaches us that they are in reality the best and most efficient protectors of our cornfields and granaries from the devastating pillage of the swarms of mice and other small rodents, which but for them would increase to the most mischievous extent. By their wholesale destruction of these petty but dangerous enemies, the owls earn an unquestionable title to be regarded as among the most active of the friends of man; a title which only one or two of them forfeit by their aggressions on his defenceless poultry.

All birds of the owl kind have one common mark, by which they are distinguished from others; their eyes, like those of tigers and cats, are formed for seeing better in the dusk, than in the broad glare of sunshine. The pupil, in fact, is capable of opening very wide, or shutting very close; and, by contracting it, the brighter light of the day, which would act too powerfully upon the sensibility of the eye, is excluded; while, by dilating the pupil, the animal takes in the more faint rays of the night, and thereby is enabled to spy its prey, and catch it with greater facility in the dark.

But though owls are dazzled by too bright a daylight, yet they do not see best in the darkest nights, as some have been apt to imagine.

The nights when the moon shines are the times of their most successful plunder: for when it is wholly dark, they are less qualified for seeing and pursuing their prey except, therefore, by moonlight, they contract the hours of their chase; and if they come out at the approach of dusk in the evening, they return before it is totally dark, and then rise by twilight the next morning, to pursue

As they are incapable of supporting the light of the day, or at least of then seeing and readily avoiding their danger, they keep all this time concealed in some obscure retreat, suited to their gloomy appetites, and there continue in solitude and silence. The cavern of a rock, the darkest part of a hollow tree, the battlements of a ruined unfrequented castle, or some obscure hole in a farmer's outhouse, are the places where they are usually found: if they be seen out of these retreats in the daytime, they may be considered as having lost their way; as having by some accident been thrown into the midst of their enemies, and surrounded with danger.

In this distress they are obliged to take shelter in the first tree or hedge that offers, there to continue concealed all day, till the returning darkness once more supplies them with a better plan of the country. But it too often happens that with all their precaution to conceal themselves, they are spied out by the other birds of the place, and are sure to receive no mercy. The blackbird, the thrush, the jay, the bunting, and the redbreast, all come in file, and employ their little arts of insult and abuse. The smallest, the feeblest, and the most contemptible of this unfortunate bird's enemies are then the foremost to injure and torment him. They increase their cries and turbulence round him, flap him with their wings, and are ready to show their courage to be great, as they are sensible that their danger is but small. The unfortunate owl, not knowing where to attack, or whither to fly, patiently sits and suffers all their insults. Astonished and dizzy, he only replies to