OCTANDRIA, in botany, the eighth class in Linnæus's system, consisting of plants with hermaphrodite flowers, which are furnished with eight stamina or male organs of generation. There are four orders belonging to this class of plants which derive their names from the number of female organs possessed by the plants of each respective division.

OCTANT, or Octile, in astronomy, that aspect of two planets, wherein they are distant an eighth part of a circle, or 45o from each other.

OCTAVE, in music, an harmonical interval, consisting of seven degrees, or lesser intervals. See MUSIC.

OCTOBER, in chronology, the tenth month of the Julian year, consisting of thirty-one days: it obtained the name of October from its being the eighth month in the calendar of Romulus. See the articles MONTH and YEAR.

ODE, in poetry, a song, or a composition proper to be sung. Among the ancients odes signified no more than songs; but with us they are very different things. The ancient odes were generally composed in honour of their gods, as many of those of Pindar and Horace. These had originally but one stanza, or strophe, but afterwards they were divided into three parts, the strophe, the antistrophe, and the epode. The priests going round the altar singing the praises of the gods, called the first entrance, when they turned to the left, the strophe; the second, turning to the right, they called antistrophe, or returning; and, lastly, standing before the altar, they sung the remainder, which they called the epode.

OECUMENICAL, signifies the same with general, or universal; as oecumenical council, bishop, &c.

OEDERA, in botany, a genus of the Syngenesia Polygamia Segregata class and order. Natural order of Compositæ Oppositifolia. Corymbiferiæ, Jussieu. Essential character: calyxes many flowered; corrollets tubular, hermaphrodite with one or two female ligulate florets; receptacle chaffy; down of several chaffs. There are two species, viz. O. prolifera, and O. aliena, both natives of the Cape of Good Hope.

OENANTHE, in botany, dropwort, a genus of the Pentandria Digynia class and order. Natural order of Umbellatæ, or Umbelliferæ. Essential character: florets

crowned with the calyx and pistil. There are eleven species; of which O. crocata, hemlock water dropwort, commonly grows four or five feet high, with strong jointed stalks, which being broken emit a yellowish fetid juice; the leaves are similar to those of hemlock, but of a lighter green colour; the roots divide into four or five larger taper ones, having some resemblance to parsneps, for which they have been taken. It grows naturally in several parts of Europe, on the banks of ditches, rivers, and lakes.

OENOTHERA, in botany, tree primrose, a genus of the Octandria Monogynia class and order. Natural order of Calycanthemæ. Onagræ, Jussieu. Essential character: calyx four-cleft; petals four; capsule cylin drical, inferior; seeds naked. There are eleven species; of which O. biennis, broadleaved tree primrose, has a fusiform, fibrous root; from this, the first year, arise many obtuse leaves, spreading flat upon the ground; from among these, the second year, come out the stems, three or four feet in height, upright, of a pale green colour; flowers solitary, each being separated by a leaflet, or bracte; they usually open between six and seven o'clock in the evening; for this reason the plant is called evening, or night primrose; the mode of their expanding is curious; the petals are held together at top by the hooks at the end of the calyx; the segments of which first separate at bottom, discovering the corolla, a long time before it acquires sufficient expansive force to unhook the calyx at top; when it has accomplished this, it expands almost instantaneously to a certain point, it then makes a stop, taking time to spread out quite flat; it may be half an hour from the first bursting of the calyx at bottom to the final expansion of the corolla, which commonly becomes flaccid in the course of the next day, according to the heat or coolness of the weather; the uppermost flowers appear first in June; the stalks keep continually advancing in height, and there is a constant succession of flowers till late in autumn. It is a native of North America.

OESOPHAGUS, the gula, or gullet, is a membranaceous canal, reaching from the fauces to the stomach, and conveying into it the food taken in at the mouth. Its figure is somewhat like that of a funnel, and its upper part is called by anatomists the pharynx. See ANATOMY.

OESTRUS, in natural history, gad-fly, a genus of insects of the order Diptera.

Month with a simple aperture, and not exserted; feelers two, of two articulations orbicular at the tip, and seated each side in a depression of the mouth; antennæ of three articulations, the last subglobular, and furnished with a bristle on the fore-part, placed in two hollows on the front. The face of this singular genus is broad, depressed, vesicular, and glaucous, and has some sort of resemblance to the ape kind. They are extremely troublesome to horses, sheep, and cattle, depositing their eggs in different parts of the body, and producing very painful tumours, and sometimes death. The larva are without feet, short, thick, and annulate, and often furnished with small hooks. There are twelve species, named from the animals which they infest: thus we have O. bovis, O. equi, O. ovis, O. hominis, &c. The principal European species is the O. bovis, or ox gad-fly, which is the size of a common bee, and is of a pale yellowish colour, with the thorax marked with four longitudinal dusky streaks, and the abdomen by a black bar across the middle; the lip is covered with tawny orange-coloured hairs; the wings are pale-brown, and unspotted. The female of this species, when ready to deposit her eggs, fastens on the back of a heifer, or cow, and piercing the skin with the tube situated at the lip of the abdomen, deposits an egg in the puncture, and then proceeds to another spot at some distance from the former, repeating the same operation, at intervals, on many parts of the animal's back. The pain which this operation occasions is extreme; and hence cattle, as if foreseeing their cruel enemy, are observed to be seized with the most violent horror when apprehensive of the approaches of the female oestrus, flying instantly to the nearest pond or pool of water; it having been observed that this insect rarely attacks cattle when standing in water. The eggs are laid in Angust or September, and the larvæ remain till the following summer before they undergo the change to the pupa state. At this period they force them selves out of their respective cells, and falling to the ground, creep beneath the first convenient shelter, and lying in an inert state become contracted into an oval form, but without casting the larva skin, which dries and hardens round them. When the included insect is ready for exclusion, it forces open the top of the pupa coat, and emerges in its perfect form, having remained within the chrysalis somewhat more than a month. We shall give an account of the O. equi, VOL. V.

from the Transactions of the Linnæan Society, drawn up with great accuracy by Mr. Clarke. "When the female has been impregnated, and the eggs are sufficiently mature, she seeks among the horses a subject for her purpose; and approaching it on the wing, she holds her body nearly upright in the air, and her tail, which is lengthened for the purpose, curved inwards and upwards in this way she approaches the part where she designs to deposit her egg; and, suspending herself for a few seconds before it, suddenly darts upon it, and leaves her egg adhering to the hair: she hardly appears to settle, but merely touches the hair with the egg held out on the projected point of the abdomen. The egg is made to adhere by means of a glutinous liquor secreted with it. She then leaves the horse at a small distance, and prepares a second egg, and, poising herself before the part, deposits it in the same way. The liquor dries, and the egg becomes firmly glued to the hair: this is repeated by various flies, till four or five hundred eggs are sometimes placed on one horse. The horses, when they become used to this fly, and find that it does them no injury, as the Tabani and Conopes, by sucking their blood, hardly regard it, and do not appear at all aware of its insidious object. The skin of the horse is always thrown into a tremulous motion on the touch of this insect, which merely arises from the very great irritability of the skin and cutaneous muscles at this season of the year, occasioned by the continual teasing of the flies, till at length these muscles act involuntarily on the slightest touch of any body whatever.

"The inside of the knee is the part on which these flies are most fond of depositing their eggs, and next to this, on the side and back part of the shoulder, and, less frequently, on the extreme ends of the mane. But it is a fact worthy of attention, that the fly does not place them promiscuously about the body, but constantly on those parts which are most liable to be licked with the tongue; and the ova, therefore, are always scrupulously placed within its reach.

"The eggs thus deposited I at first supposed were loosened from the hairs by the moisture of the tongue, aided by its roughness, and were conveyed to the stomach, where they were hatched: but on more minute search I do not find this to be the case, or at least only by accident; for, when they have remained on the hairs four or five days they become ripe, after which

Ꭰ

time the slightest application of warmth and moisture is sufficient to bring forth, in an instant, the latent larva. At this time, if the tongue of the horse touches the egg, its operculum is thrown open, and a small active worm is produced, which readily adheres to the moist surface of the tongue, and is from thence conveyed with the food to the stomach. If the egg itself be taken up by accident, it may pass on to the intestinal canal before it hatches; in which case its existence to the full growth is more precarious, and certainly not so agreeable, as it is exposed to the bitterness of the bile.

"I have often, with a pair of scissars, clipped off some hairs with eggs on the from the horse, and on placing them in the hand, moistened with saliva, they have hatched in a few seconds. At other times, when not perfectly ripe, the larva would not appear, though held in the hand under the same circumstances for several hours; a sufficient proof that the eggs themselves are not conveyed to the stomach. It is fortunate for the animal infested by these insects that their numbers are limited by the hazards they are exposed to. I should suspect near a hundred are lost for one that arrives at the perfect state of a fly. The eggs, in the first place, when ripe, often hatch of themselves, and the larva, without a nidus, crawls about till it dies; others are washed off by water, or are hatched by the sun and moisture thus supplied together. When in the mouth of the animal they have the dreadful ordeal of the teeth and mastication to pass through. On their arrival at the stomach, they may pass mixed with the mass of food into the intestines; and when full grown, in dropping from the animal to the ground, a dirty road or water may receive thein. If on the commons, they are in danger of being crushed to death, or of being picked up by the birds who so constantly attend the footsteps of the cattle for food. Such are the contingencies by which nature has wisely prevented the too great increase of their numbers, and the total destruction of the animals they feed on.

"I have once seen the larva of this estrus in the stomach of an ass; indeed there is little reason to doubt their existence in the stomachs of all this tribe of animals. These larva attach themselves to every part of the stomach, but are generally most numerous about the pylorus, and are sometimes, though much less frequently, found in the intestines. Their numbers in the stomach are very various, often not more than half a

dozen, at other times more than a hundred; and, if some accounts might be relied on, even a much greater number than this. They hang most commonly in clusters, being fixed by the small end to the inner membrane of the stomach, which they adhere to by means of two small hooks, or tentacula. When they are removed from the stomach they will attach themselves to any loose membrane, and even to the skin of the hand. The body of the larva is composed of eleven segments, all of which, except the two last, are surrounded with a double row of horny bristles, directed towards the truncated end, and are of a reddish colour, except the points, which are black. The larva evidently receive their food at the small end, by a longitudinal aperture, which is situated between two hooks, or tentacula. Their food is probably the chyle, which, being nearly pure, aliment, may go wholly to the composition of their bodies without any excrementitious residue, though on dissection the intestine is found to contain a yellow or greenish matter, which is derived from the colour of the food, and shows that the chyle, as they receive it, is not perfectly pure. They attain their full growth about the latter end of May, and are coming from the horse from this time to the latter end of June, or sometimes later. On dropping to the ground they find out some convenient retreat, and change to the chrysalis; and in about six or seven weeks the fly appears.

This

"The perfect fly but ill sustains the changes of weather; and cold and mois ture, in any considerable degree, would probably be fatal to it. These flies never pursue the horse into the water. aversion I imagine arises from the chillness of that element, which is probably felt more exquisitely by them, from the high temperature they had been exposed to during their larva state. The heat of the stomach of the horse is much greater than that of the warmest climate, being about 102 degrees of Fahrenheit, and in their fly state they are only exposed to 60, and from that to about 80 degrees. This change, if suddenly applied, would in all probability be fatal to them; but they are prepared for it by suffering its first effects in the quiescent and less sensible state of a chrysalis. I have often seen this fly, during the night time and in cold weather, fold itself up with the head and tail nearly in contact, and lying apparently in a torpid state through the middle of the summer."

O. ovis: wings pellucid, punctured at the

base; abdomen variegated with white and black. It deposits its eggs on the inner margin of the nostrils of sheep, occasioning them to shake their heads violently, and hide their noses in the dust or gravel. The larva crawl up into the frontal sinuses, and when full fed are again discharged through the nostrils. See Pl. III. Entomology, fig.7 and 8. OFFENCE, is any act committed against any law. Offences are either capital, or not capital. Capital offences are those for which the offender loses his life; not capital, where the offender may lose his lands and goods, be fined, or suffer corporal punishment, or both, but which are not subject to the loss of life.

OFFERINGS. Oblations and offerings partake of the nature of tithes; and all persons who by law ought to pay their of ferings, shall yearly pay to the parson, vicar, proprietary, or their deputies, or farmers of the parishes where they dwell, at such four offering days as heretofore within the space of four years last past hath been accustomed, and in default thereof shall pay for the said offerings at Easter following.

gives a bond to the principal to pay him a sum certain, without reference to the profits, this is void under the statute.

To offer money to any officer of state, to procure the reversion of an office in the gift of the crown, is a misdemeanor at common law, and punishable by information; and. even the attempt to induce him, under the influence of a bribe, is criminal, though never carried into execution. An instance of which occurred under the administration of Mr. Addington, who prosecuted a tinman for offering a sum of money to him for a place in the customs.

Any contract to procure the nomination to an office, not within the statute 6 Edward VI, is defective on the ground of pub. lic policy; and the money agreed to be given is not recoverable.

OFFICER, a person possessed of a post or office.

The great officers of the crown, or state, are the Lord High Steward, the Lord High Chancellor, the Lord High Treasurer, the Lord President of the Council, the Lord Privy Seal, the Lord Chamberlain, the Lord High Constable, the Earl Marshall: each of which see under its proper article.

OFFICERS, commission, are those appoint

The statute 5 and 6 Edward VI. c. 16, declares all securities given for the sale of offices unlawful. And if any person shall bargain, or sell, or take any reward, or promise of reward, for any office, or the deputation of any office, concerning the reve nue, or the keeping of the king's castles, or the administration and execution of justice, unless it be such an office as had been usually granted by the justices of the King's Bench, or Common Pleas, or by justices of assize, every such person shall not only for. feit his right to such office, or to the nomination thereof; but the person giving such reward, &c. shall be disabled to hold such office.

But it has been decided that where an office is within the statute, and the salary certain, if the principal make a deputy, reserving by bond a less sum out of the salary, it is good: or, if the profits are uncertain, reserving a part, as half the profits, it is good; for the fees still belong to the principal, in whose name they must be sued for. But where a person so appointed

from the general to the cornet inclusive, who are thus denominated in contradistinc tion to warrant officers, who are appointed by the colonel's or captain's warrant, as quarter-masters, serjeants, corporals, and even chaplains and surgeons.

OFFICERS, field, are such as command a whole regiment, as the colonel, lieutenantcolonel, and major.

OFFICERS, general, are those whose command is not limited to a single company, troop, or regiment; but extends to a body of forces, composed of several regiments: such are the general, lieutenant-general, major-generals, and brigadiers.

OFFICERS, staff, are such as, in the King's presence, bear a white staff, or wand; and at other times, on their going abroad, have it carried before them by a footman, bareheaded such are the Lord Steward, Lord Chamberlain, Lord Treasurer, &c.

The white staff is taken for a commission, and at the King's death each of these officers breaks his staff over the hearse made for the King's body, and by this means lays down his commission, and discharges all his interior officers.

OFFICERS, subaltern, are all who administer justice in the name of subjects; as those

who act under the Earl Marshal, Admiral, &c. In the army, the subaltern officers are the lieutenants, cornets, ensigns, serjeants, and corporals.

OFFICIAL, by the ancient law, signifies him who is the minister of, or attendant upon, a magistrate. In the canon law, it is especially taken for him to whom any bishop generally commits the charge of his spiritual jurisdiction; and in this sense there is one in every diocese called officialis principalis, whom the laws and statutes of this kingdom call chancellor. 32 Hen. VIII. 15. OFFING, or OFFIN, in the sea-language, that part of the sea a good distance from shore, where there is deep water, and no need of a pilot to conduct the ship: thus, if a ship from shore be seen sailing out to seaward, they say, she stands for the offing: and if a ship, having the shore near her, have another a good way without her, or to wards the sea, they say, that ship is in the offing.

OFF SETS, in gardening, are the young shoots that spring from the roots of plants; which being carefully separated, and plant ed in a proper soil, serve to propagate the species.

OFF-SETS, in surveying, are perpendiculars let fall, and measuring from the sta tionary lines to the hedge, fence, or extremity of an enclosure.

OGEE, or O. G., in architecture, a moulding, consisting of two members, the one concave and the other convex; or, of a round and a hollow, like an S.

OGIVE, in architecture, an arch, or branch of a Gothic vault; which, instead of being circular, passes diagonally from one angle to another, and forms a cross with the other arches.

OIL. The general character of oils are combustibility, insolubility in water, and fluidity. From the peculiar properties of different oils, they are naturally divided into two kinds; fixed or fat oils, and volatile or essential oils. The fixed, or fat oils, require a high temperature to raise them to the state of vapour, a temperature above that of boiling water; but the volatile, or essential oils, are volatilized at the temperature of boiling water, and even at a lower one. Both the volatile and fixed oils are obtained from plants, and sometimes from the same plant; but always from different parts of it. While the seeds yield fixed oil, the volatile oil is extracted from the bark or wood. One of the most distinguishing characteristics of the fixed oils is, that

they exist only in one part of the vegetabler in the seeds. No trace of fixed oil can be detected in the roots, the stem, leaves, or flowers of those plants, whose seeds afford it in great abundance. The olive may seem an exception to this. The oil which it yields is extracted, not from the seeds, but from its covering. Among plants too, fixed oils are only found existing in those whose seeds have a peculiar structure. The seeds of plants have sometimes one lobe, in which case they are called "monocotyledonous" plants; and sometimes they have two, when they are denominated "dicotyledonous." The formation of fixed oil in plants is exclusively limited to the latter class. There is no instance of fixed oils being found in the seeds of plants which have only one lobe. Those seeds which yield the fixed oils contain also a considerable portion of mucilage, so that when such seeds are bruised and mixed with water, they form what is called an emulsion, which is a white fluid containing a quantity of the oil of the seed mixed with the mucilage. Fixed oils are extracted from the seeds of a great number of plants. Those which yield it in greatest abundance are, the olive, thence called olive oil; the seeds of lint, and the kernels of almonds, called linseed, or almond oil. Fixed oils are also obtained from animals; such as train oil, as it is called, which is extracted from the fat or blubber of the whale. Fixed oil is obtained also in great abundance from the liver of animals, and is found to exist in the eggs of fowls. These different kinds of fixed oils, although they possess many common properties, yet in others they are very different. Many of the vege table oils have no smell, and scarcely any perceptible taste. The animal oils, on the contrary, are generally extremely nauseous and offensive. These differences are supposed to be owing to the mixture of extraneous bodies, or to certain chemical changes which arise from the action of these bodies upon each other, or on the oil itself. As the fixed oils exist ready formed in the seeds of plants, they are generally obtained by

expression," ," and hence they have been called "expressed oils," This is done by reducing the seeds to a kind of pulp, or paste, which is inclosed in bags, and subjected by means of machinery, when it is obtained in the large way, to strong pressure, so that the oil flows out, and is easily collected. The oil which is obtained by this process, which has been called “ cold drawn oil," because it is procured without the ap