will drive a bullet with great violence, by means of condensed air, forced into an iron ball by a condenser. Fig. 11. represents the condenser for forcing the air into the ball. At the end of this instrument is a male screw, on which the hollow ball, b, is screwed, in order to be filled with condensed air. In the inside of this ball is a valve, to hinder the air, after it is injected, from making its eseape, until it be forced open by a pin, against which the hammer of the lock strikes; which then lets out as much air as will drive a ball with considerable force to a great distance.

When you condense the air in the ball, place your feet on the iron cross, h h, to which the piston-rod, d, is fixed; then lift off the barrel e a, by the handles, i i, until the end of the piston is brought between e and c; the barrel, a c, will then be filled with air through the hole, e. Then thrust down the barrel, a c, by the handles, i i, until the piston, e, join with the neck of the iron ball at a; the air being thus condensed between e and a, will force open the valve in the ball, and when the handles are lifted up again, the valve will close and keep in the air; in this manner the ball will presently be filled; after which, unscrew the ball of the condenser, and screw it upon another male screw, which is connected with the barrel, and goes through the stock of the gun, as represented, (fig. 12.) The whole will be better understood by fig. 13, which is a section of the gun. The inside, k, is that from which the bullets are shot, and CDS R, is a larger barrel. In the stock of the gun, M, which forces the air through the valve E P, into the cavity between the two barrels, there is a valve at S L, which being opened by the trigger O, permits the air to rush suddenly behind the bullet, so as to drive it out with great force. If the valve is suddenly opened and closed, one charge of condensed air may make several discharges of bullets.

PNEUMORA, in natural history, a genus of insects of the order Hemiptera.— Body ovate, inflated, diaphanous : head inflected, armed with jaws; thorax convex, carinate beneath; wing-cases deflected, membranaceous, legs formed for running. There are only three species, viz. 1. P. immaculata: green spotted with white; wing-cases immaculate. 2. P. maculata wing-cases green, with square white spots. And, 3. P. guttata: wingcases green, with two white spots : abdomen with three white spots on each side.

They are all found at the Cape of Good Hope. The insects of this genus appear to consist of a mere hollow inflamed membrane: by rubbing together their serrate, or toothed legs, they make a shrill kind of noise morning and evening, and follow a light; and they are so nearly allied to the cricket tribe, that they have been enumerated by some naturalists under the genus Gryllus.

POA, in botany, meadow grass, a genus of the Triandria Digynia class and order. Natural order of Gramina, or grasses.Essential character: calyx two-valved, many-flowered: spikelet ovate; valves scariose at the edge, and sharpish. There are seventy-one species.

POCKET, in the woollen trade, a word used to denote a large sort of bag, in which wool is packed up to be sent from one part of the kingdom to another. The pocket contains usually twenty-five hundred weight of wool.

PODOPHYLLUM, in botany, a genus of the Polyandria Monogynia class and order. Natural order of Rhoadeæ. Ranunculaceæ, Jussieu. Essential character: calyx three-leaved; corolla ninepetalled; berry one-celled, crowned with the stigma. There are two species, viz. P. peltatum, duck's foot, or May-apple; and P. diphyllum.

PODURA, in natural history, spring tail, a genus of insects of the order Aptera. Generic character: lip bifid; four feelers, subclavate; two eyes, composed of eight facets; antennæ filiform; body scaly ; tail forked, but under the body, and acting as a spring, hence its name; six legs, formed for running. There are thirty-one species. They feed on leaves of various plants: the larva and pupa are six-footed, nimble, and resemble the perfect insect. P. aquatica is black, and, as its name imports, aquatic; they assemble in troops early in the morning, on the banks of pools and fish-ponds. P. ambulans is white, with a bifid extended tail, and is found principally among moss.

POETICAL rising and setting of the stars. The three kinds of rising and seting, viz. the cosmical, acronical, and heliacal, were made by the ancient poets, referring the rising, &c. of the stars to that of the sun.

POETRY. Dr. Blackwall, in his "Essay on the Life and Writings of Homer," says, on the subject of poetry, that "it is of a nature so delicate, as not to admit of a direct definition; for if ever the je ne sais quoi was rightly applied, it is to the powers of poetry, and the faculty that

produces it. To go about to describe it would be like attempting to define inspiration, or that glow of fancy, or effusion of soul, which a poet feels while in his fit; a sensation so strong, that they express it only by adjurings, exclamations, and rapture." To the same purpose, but in less inflated language, Dr. Blair has observed, that it is not so easy as might at first be imagined, to ascertain, with minute precision, wherein poetry differs from prose. In point of fact, every reflecting reader must be sensible, that as it is difficult to determine the precise line where different shades of colour terminate, or even the boundaries of animal and vegetable nature, so it is a matter of no small nicety to fix the point where composition rises from the scale of prose to that of poetry. By a small addition to the ideas of Aristotle, poetry may, however, be defined an imitative and creative art, whose energies are exerted by means of words metrically arranged, the end and design of which art is to amuse the fancy, and powerfully to excite the feelings.

It is the favourite expression of Aristotle, that poetry is a mimetic or imitative art: and in most particulars it may be justly so defined. The subjects of the poet's imitation are the scenes of nature, and the transactions of human life. This we shall find to be the case, if we particularly examine the productions of those to whom the concurrent voice of ages has given the title of poet. When we open the Iliad of Homer, we behold a lively representation of the actions and speeches of heroes and chiefs. The dramas of Eschylus, of Sophocles, of Aristophanes, and of their numerous tribes of successors, are nothing more than imitations of human inanners. And when the lover displays his passion in song, what does he but exhibit to view the tablet of his heart, where we may trace his feelings, and view him agitated by doubt or exulting in hope. The chief interest of didactic poetry consists in the vivid and picturesque descriptions, the imitations or representations of nature, which relieve the insipidity of unornamented precept. This is manifest, when it is recollected, that the pleasure excited by the Georgic of Virgil is not occasioned by his agricultural instructions, but by his descriptions of the various phenomena, which in the course of rural occupations arrest the attention of the lover of nature.

The word poet, in its original import, signifies creator. And as names are not

unfrequently significant of the nature of the ideas which they represent, the name itself of poetry will direct us to one of its most distinguishing characteristics. It is indeed one of the noblest qualities of poetry, that it opens to the mind a new creation.

"The poet's eye, in a fine frenzy rolling,

Doth glance from heaven to earth, from earth to heaven;

And as imagination bodies forth The form of things unknown, the poet's pen

Turns them to shapes, and gives to airy nothing

A local habitation and a name."

The poet enjoys the privilege of ranging through the boundless field of possibilities, and of selecting his objects according to the impulse of his fancy, as controlled and corrected by the discretion of his judgment. What is striking and interesting he may make prominent in his picture; what is offensive, deformed, or gross, he is at liberty to conceal or to soften. In the realities of life a thousand circumstances intervene to check the enthusiastic interest which our hearts are disposed to take in any specific occurrence.

These circumstances the poet has a prescriptive right to exclude from his representations. As all ideas of men are primitively derived from objects of sense, he cannot go beyond the materials which the station and the powers of man supply. But he can, by an endless combination of these materials, produce ideal beings and fancied situations, which interest us the more, the better the powers of fiction to which they owe their birth are concealed from us. Like the favoured statuary of Greece, he is surrounded by naked beauties, from each of which he selects its peculiar excellency, and produces a whole, which, though strictly natural, surpasses the realities of nature.

The mathematician, in his investigation of truth, is confined to the narrow path of reason. The same may be said of the philosopher. The slightest deviation into the fields of imagination frustrates their pursuit, and disappoints their hopes of fame. The historian must found his reputation upon a patient investigation of facts, and beware of giving the loosened rein to his inventive talents. The orator, indeed, calls fancy to the aid of reason; but she ought to be strictly an auxiliary. If his edifice be not founded on the solid

basis of reason, it will fall, together with its embellishments, to the ground. In oratory, fancy embellishes the operations of judgment; but so far as poetry is a creative art, imagination is its primary cause, and judgment a secondary agent, employed to prune the luxuriant shoots of fancy.

It is the grand source of the excellence of poetic imitation, that this imitation is effected by words. Aristotle has defined words as "sounds significant:" they are significant of ideas. Men that adopt the same language, by a tacit compact, agree that certain sounds shall be the representatives of certain ideas. But ideas represent their archetypes. When, therefore, we use words, we revive in the minds of those who understand our language the pictures of the objects of which we speak. The poetic imitation then being carried on by means of words, evidently embraces all objects of which mankind have ever formed ideas. Its energies are not crippled. It expatiates in the universe, and even passes

ceded and that followed this event, in tracing the steps of the duteous son from the palace of Priam to his father's mansion, and in beholding him at length bearing his parent beyond the reach of the foe. Aristotle's doctrine, that a finished composition should have a beginning, a middle, and an end, is founded on reason; and the mind feels a superior degree of satisfaction, when the rise, the circumstances, and the consequences of events, are displayed before it in artful order.

But the poetic imitation or representation is effected, not merely by words, but by words metrically, or at least melodiously arranged.

Melody is naturally pleasing to the human ear and it is not surprising, that the cultivators of an art, whose province it is to delight, should be careful in bringing as nearly as possible to perfection the melody of their numbers. It is astonishing with what accuracy the Greeks and Romans attended to this particular; how minutely they weighed the value of almost every syllable; how strictly their bards were obliged to conform to the es

time."

This circumstance is justly noted by the ingenious Mr. Harris, as bestowing upon poetry a decisive superiority over the art of painting. The energies of painting are confined to those objects, that can be represented by colour and figure. Poetry can also express these objects, though, it must be confessed, with a far inferior degree of exquisiteness: but this deficiency is amply compensated by the extensive range of the poet's excursions. He dives into the human heart, developes the windings of the heart, portrays in all their circumstances the workings of the passions, gives form and body to the most abstract ideas, and, by the language which he puts into the mouths of his characters, he unlocks the secrets of their mind. There is another grand advantage which the poet possesses over the painter, namely, that the latter is confined to the transactions that happen in a moment of time; while the former presents to our view a long series of consecutive events. An interesting picture might no doubt be drawn of the pious agony with which Eneas witnessed the obstinacy of his father, in refusing to save himself from the sword of the Greeks by quitting his ancient and long-loved abode; but what a varied pleasure do we experience in reading of the circumstances that pre

and in our own language, greater latitude is allowed; yet almost every reader of poetry is aware of the charms of melodious composition. What a sensible difference do we perceive between the careless couplets of Churchill and the polished numbers of Pope. How much more pleasing to the ear are the measured sentences of M'Pherson, than a host of lines which we sometimes find printed in the form of verses.

But though melodious and metrical arrangement of words be one of the characteristics, and, as Dr. Blair denominates it, "the exterior distinction" of poetry, it is necessary to observe, that too many writers seem to assign to this characteristic a place of eminence to which it is by no means entitled. In consequence of this error, vast multitudes of compositions are obtruded upon the world under the name of poems, which possess no other merit than that of regularity of versification and smoothness of numbers. Against these wearisome productions Horace has long ago protested, in his memorable declaration, that the quality of mediocrity is denied to poets, and that poetry includes something more in its definition than the measuring of syllables and the tagging of a verse. If the heart does not glow with the flame of genius, the mechanism of art will be of no avail. No one can excite strong feelings in

others, who is not himself strongly excited; no one can raise vivid images in the mind of his reader, who is not himself illuminated by the sportive light of fancy. Verses strictly and legitimately measured out, with due attention to pause and cadence, but devoid of the animating spirit which characterizes true poetry, are, like the human body when deprived of the principle of life, cold, cheerless, and offensive.

He who aspires after the title of poet should never, indeed, forget, that the end of poetry is to amuse the fancy, and powerfully to excite the feelings, and that this is effected by impressing the mind with the most vivid pictures. In the course of her operations, poetry hurries us beyond the reach of sober judgment, and captivates by rousing the energy of passion. Here then we see the cause of the power of verse, nor wonder at the efficaciousness which has, more especially in early times, been ascribed to the muses. For how easily are mankind guided by those who possess the art of awakening or of allaying their feelings. Though all unconscious of being under the guidance of another, they turn obedient to the rein. They are roused to insurrection, or moderated to peace, by him who can touch with a skilful hand the master springs that regulate the motions of their minds. "The primary aim of a poet," says Dr. Blair, "is to please and to move; and therefore it is to the imagination and the passions that he speaks. He may, and he ought to have it in his view, to instruct and to reform: but it is indirectly, and by pleasing and moving, that he accomplishes this end. His mind is supposed to be animated by some interesting object, which fires his imagination, or engages his passions; and which of course communicates to his style a peculiar elevation, suited to his ideas, very different from that mode of expression which is natural to the mind in its calm ordinary state."

As then it appears to be the leading end of poetry to make a lively impression on the feelings, we may judge as it were à priori of the amazing intenseness of its powers, and we shall find our judgment verified when we come to inquire into the fact. In consequence of the efficacy of poetry upon the human feelings, the maxims of early wisdom, the first records of history, the solemn offices of religion, nay even the dictates of law, were delivered in the poetic dress. VOL. X.

In the infancy of states, poetry is a method equally captivating and powerful of forming the dispositions of the people, and kindling in their hearts that love of glory which is their country's safeguard in the day of peril. Whether we look to the cold regions of Scandinavia, or the delicious clime of Greece; whether we contemplate the North American Indian, or the wild Arab of the desert; we find, that when mankind have made a certain progress in society, they are strongly influenced by a love of song, and listen with raptured attention to the strains that record the tales of other times, and the deeds of heroes of old. They listen till they imbibe the enthusiasm of warfare, and in the day of battle the hero's arm has not unfrequently been nerved by the rough energy of the early bard. It is a well known fact, that the Greeks were accustomed to march to the fight while singing in praise of Apollo, and that the songs written in honour of Harmodius and Aristogiton, by being habitually recited at their banquets and solemn festivals, tended in no inconsiderable degree to preserve among the Athenians an enthusiastic love of liberty. Nor is the power of the muses done away by the progress of civilization. Every nation, at every period of its existence, possesses some indigenous poetry, which nourishes the flame of patriotism.

Such is the wonderful influence of poetical composition. Like all other powerful instruments, it may be, and it has been, abused. But when directed to worthy objects, it is one of the most pleasant and most efficacious means of forming the youthful mind, and of exciting the emotions and enforcing the principics of virtue.

POHLIA, in botany, a genus of the Cryptogamia Musci class and order. Generic character: capsule ovate, oblong, placed on an abconical, narrower apophysis; peristome double: outer with sixteen broadish teeth: inner with a sixteen parted membrane. Males gemmaceous, on a distinct plant.

POINT, in geometry, as defined by Euclid, is a quantity which has no parts, or which is indivisible. Points are the ends or extremities of lines. If a point be supposed to be moved any way, it will, See by its motion, describe a line.

POINT, in astronomy, a term applied to certain points or places, marked in the heavens, and distinguished by proper epithets. The four grand points or divisions of the horizon, viz. the east, west, north, and south, are called the cardinal points. The zenith and nadir are the vertical points; the points wherein the orbits of the planets cut the plane of the ecliptic are called the nodes: the points wherein the equator and ecliptic intersect are called the equinoctial points; particularly that whence the sun ascends towards the north pole, is called the vernal point; and that by which he descends to the south pole, the autumnal point. The points of the ecliptic, where the sun's ascent above the equator, and descent below it, terminate, are called the solsticial points; particularly the former of them, the estival, or summer point; the latter, the brumal, or winter point.

POINT of the horizon, or compass, in navigation and geography.

POINT is also used for a cape or headland, jutting out into the sea: thus, seamen say, two points of the land are in one another, when they are so in a right line against each other, as that the innermost is hindered from being seen by the outer

most.

POINT, in perspective, is used for various parts or places, with regard to the perspective plane. See PERSPEC

TIVE.

POINTS, in heraldry, are the several different parts of an escutcheon, denoting the local positions of any figure. There are nine principal points in an escutcheon: the dexter chief: the precise middle chief; the sinister chief; the honour point; the fess-point, called also the centre; the nombril point, that is, the navel point; the dexter base; the sinister base; the precise middle base.

POINT is also used in heraldry for the lowest part of the escutcheon, which usually terminates in a point.

POINT is also an iron or steel instrument, used with some variety in several

arts.

Engravers, etchers, cutters in wood, &c. use points to trace their designs on the copper, wood, stone, &c. See ENGRAVING.

POINT, in the manufactories, is a general term used for all kinds of laces, wrought with the needle; such are the point de Venice, point de France, point de Genoa, &c. which are distinguished by the particular economy and arrangement of their points. Point is sometimes used for lace woven with bobbins, as English point, point de Malines, point d'Havre, &c.

POINT of view, with regard to building, painting, &c. is a point at a certain distance from a building or other object, in which the eye has the most advantageous view of the same. This point is usually at a distance equal to the height of the building.

POINT blank, in gunnery, is the horizontal position of a gun. The point blank range is the distance the shot goes before it strikes the level ground, when discharged in the horizontal or point blank direction. See GUNNERY.

POINTED, in heraldry. A cross pointed, is that which has the extremities turned off into points by straight lines.

POINTING, in grammar, the art of dividing a discourse, by points, into periods, and members of periods, in order to show the proper pauses to be made in reading, and to facilitate the pronunciation and understanding thereof. PUNCTUATION.

See

POINTING, in war, the levelling a cannon or mortar, so as to play against any certain point. See GUNNERY, &c.

POINTING the cable, in the sea language, is untwisting it at the end, lessening the yarn, twisting it again, and making all fast with a piece of marline, to keep it from ravelling out.

POISONS, those substances, which, when applied externally, or taken into the human body, uniformly cause such a derangement of the animal economy as to produce disease. As it is extremely difficult, however, to give a definition of a poison, the above is subject to great inaccuracy. Poisons are divided, with respect to the kingdom to which they belong, into animal, vegetable, mineral, and vaporous poisons. Poisons are only deleterious in certain doses; for the most active, in small doses, form very valuable medicines. There are,nevertheless,certain poisons, which are really such in the smallest quantity, and which are never administered medicinally, as many of the animal