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which sometimes visit us from countries still farther north, prove that nature has not confined her works of elegance to regions within the tropics.

The whole class of birds differs essentially from all other animals in internal structure, 2s well as in external form and appearance; and every point of difference, when accurately examined, is evidently adapted to their peculiar habits. These will be noticed under the several orders and genera. To give but a single instance in this place: the accipitres have sight so piercing, that frequently, when so high as to be out of human ken, they can descry their prey upon the ground, and their flight is so rapid, that they can dart upon it with the celerity of a meteor. Their prey varies according to their strength and rapacity, from the lamb or kid, which the vulture bears away in his talons, to the smaller birds and mice, on which the hawk and owl tribes feast. To prevent the depredation that these would otherwise commit, nature has ordained that this tribe of birds should be the least prolific; few of them lay more than two eggs.

AUGEA, in botany, a genus of the Decandria Monogynia class and order. Calyx five-parted; corolla of nectary ten-toothed; capsule ten-celled. One species, a native of the Cape.

AUGITE, a mineral of the Chrysolite family, foundin basalt, sometimes in grains, but most commonly in crystals, mostly small and complete. Colour blackish green, sometimes passing into leek green, and rarely to liver brown. Specific gravity 3.22 to 3.47. Before the blow-pipe it is with difficulty converted into a black enamel: the constituent parts are

Silica......... -------- 52.00

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olivino by its darker colours, different crystallization, greater hardness, and specific gravity. It used to be considered as a product of fire; but the circumstance of its occurring wrapped up, not imbedded in lava, demonstrates that it is one of the constituent parts of the mother-stone, which has escaped fusion. AUGMENT, in grammar, an accident of certain tenses of Greek verbs, being either the prefixing of a syllable, or an increase of the quantity of the initial vowels. Of these there are two kinds, the augmentum temporale, or of a letter, when a short vowel is changed into a long one, or a diphthong into another longer one; and augmentum syllabicum, or of a syllable, when a syllable is added at the beginning of the word. AUGMENTATION, was the name of a court erected 27 Hen. VIII. so called from the augmentation of the revenues of the crown, by the suppression of religious houses, and the office still remains, wherein there are many curious records, though the court has been dissolved long since. AUGMENTAtion, in heraldry, are additional charges to a coat-armour, frequently given as particular marks of honour, and generally borne either on the escutcheon or a canton; as have all the baronets of England, who have borne the arms of the province of Ulster in Ireland. AUGMENTAtion, in music, a term confined to the language of fuguists, and is the doubling the value of the notes of the subject of a fugue or canon: or, the giving the intervals of the subject in notes of twice the original length. AUGRE, or Awgre, an instrument used by carpenters and joiners to bore large round holes, and consisting of a wooden handle and an iron blade, terminated at bottom with a steel bit. AVIARY, a place set apart for feeding and propagating birds. It should be so large, as to give the birds some freedom of flight; and turfed, to avoid the appearance of foulness on the floor. See Apis and Bees. AVICENA, Ebu SINA, in biography, has been accounted the prince of Arabian philosophers and physicians. He was born at Assena, near Bokhara, in 973; and died at Hamadan in 1036, being 58 years of age. The first years of Avicema were employed in the study of the Belles Lettres, and the Koran, and at ten years of age he was per fect master of the hidden senses of that

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book. Then applying to the study of logic, philosophy, and mathematics, he quickly made a rapid progress. After studying under a master the first principles of logic, and the first five or six propositions of Euclid's elements, he became disgusted with the slow manner of the schools, applied himself alone, and soon accomplished all the rest by the help of the commentators only. Possessed with an extreme avidity to be acquainted with all the sciences, he studied medicine also. Persuaded that this art consists as much in practice as in theory, he sought all opportunities of seeing the sick; and afterwards confessed that he had learned more from such experience than from all the books he had read. Being now in his sixteenth year, and already celebrated for being the light of his age, he determined to resume his studies of philosophy, which medicine, &c. had made him for some time neglect: and he spent a year and a half in this painful labour, without ever sleeping all this time a whole night together. At the age of 21, he conceived the bold design of incorporating in one work all the objects of human knowledge; and he carried it into execution in an Encyclopedia of 20 volumes, to which he gave the title of the “Utility of Utilities.” Many wonderful stories are related of his skill in medicine, and the cures which he performed. Several princes had been taken dangerously ill, and Avicena was the only one that could know their ailments, and cure them. His reputation increased daily, and all the princes of the East desired to retain him in their families, and in fact he passed through several of them. But the irregularities of his conduct sometimes lost him their favour, and threw him into great distresses. His excesses in pleasures, and his infirmities, made a poet say, who wrote his epitaph, that the profound study of philosophy had not taught him good morals, nor that of medicine the art of preserving his own health. After his death, however, he enjoyed so great a reputation, that till the 12th century he was preferred for the study of philosophy and medicine to all his predecessors. Even in Europe his works, which were very mumerous, were the only writings in vogue in the schools. AVICENNIA, in botany, so named in honour of a celebrated oriental physician, who flourished in the eleventh century at Ispahan, a genus of the Didynamia Angiospermia class and order. Essential charac. ter: calyx five-parted; corolla two-lipped,

the upper lip square; capsule coriaceons, rhomboid, one-seeded. There are three species, natives of the East and West Indies. A. tomentosa, a tree, agrees mostly with the mangrove, rising about 15 feet; its trunk is not so large, having a smooth, whitish green bark, and from the stem are twigs propagating the tree like that: the branches at top are jointed towards their ends where, the leaves come out opposite, on very small petioles, two inches and a half long, and about an inch broad: the flowers are many at the top of the branches, white and tetrapetalous. It is found on the north and south sides of Jamaica, growing in low moistground, A. nitida grows forty feet high, a native of Martinico: the creeping roots throw up abundance of suckers. A. resinifera produces a green coloured gum, so much esteemed by the natives of New Zealand, and which is very hot in the mouth. AVIGNON berry, taken from the rhamnus infectorius, and used in France by dyers for making a yellow colour. They are gathered unripe, bruised, and boiled in water, mixed with the ashes of vine stalks to give a body, and then strained through linen. The colour is chiefly used for silk, but it will not well bear the heat of the sun. The plant grows, as its name imports, in the neighbourhood of Avignon. AULA regis, was a court established by William the Conqueror in his own hall. It was composed of the king's great officers of state resident in his palace, who usually attended on his person, and followed him in all his progresses and expeditions; which being found inconvenient and burthensome, it was enacted by the great charter, c. 11, that common pleas shall no longer follow the king's court, but shall be holden in some certain place, which certain place was established in Westminster Hall, where the aula regis originally sat when the king resided in that city, and there it has ever since continued. 3 Black. 37. AULIC, an epithet given to certain officers of the empire, who compose a court, which decides, without appeal, in all processes entered in it. Thus we say, aulic council, aulic chamber, aulic counsellor, The aulic council is composed of a president. who is a Catholic; of a vice-chancellor, presented by the archbishop of Mentz; and of eighteen counsellors, nine of whom are Protestants, and nine-Catholics. They are divided into a bench of lawyers, and always follow the emperor's court, for which reason they are called justitium imperatoris, the em

peror's justice, and anic council. The aulic court ceases at the death of the emperor, whereas the imperial chamber of Spire is perpetual, representing not only the deceased emperor, but the whole Germanic body, which is reputed never to die.

AVOIRDUPOIS, or Averdupois weight, a sort of weight used in England, the pound whereof is made up of sixteen ounces.

This is the weight for the larger and coarser commodities, such as groceries, cheese, wool, iead, &c. Bakers who live not in corporation-towns, are to make their bread by avoirdupois weight, those in corporations, by troy weight. Apothecaries buy by avoirdupois weight, but sell by troy. The avoirdupois ounce is less than the troy ounce, in the proportion of 700 to 768; but the avoirdupois pound is greater than the troy pound in the proportion of 700 to 576, or as 17 to 14 nearly: for

1 lb. avoirdupois = 7000 grains troy. 1 lb. troy.......... = 5760......... 1 oz. avoirdupois = 4374. 1 oz. troy.......... = 480 ......... do.

AVOWEE, one who has a right to present to a benefice. See Advowson.

AURELIA, in natural history, a term formerly employed by naturalists to express that intermediate state in which all lepidopterous, and most other insects, remain for some time, between the caterpillar form and the period in which they are furnished with wings, with antennae, and other organs appertaining to the perfect insect. Aurelia and crysalis are synonymous words, both alluding to the golden splendour of the case in which the creature, during that state, is contained. This brilliant appearance seems to be confined to the Papilio tribe, so that the terms aurelia and chrysalis are altogether inapplicable, in a general manner, to insects in that state. These terms are now discarded in favour of the more expressive one pupa, which Linnaeus has adopted in their stead; a term which implies that the insect, like anjnfant, remains in its swaddling clothes. - AURICLE, in anatomy, that part of the ear which is prominent from the head, called by many authors auriserterna.

AUR1cles of the heart. These are a kind of appendages of the heart at its base, and are distinguished by the names of the right and left. The right auricle is much larger than the left, and this is placed in the hinder,

that in the anterior part. They are intended as diverticula for the blood, during the systole. Their substance is muscular, being composed of strong fibres, and their motion is not synchronous but achronous with that of the heart. See ANAtomy. AURICULAR medicines, such as are used in the cure of distempers in the ear. AURIGA, the Waggoner, in astronomy, a constellation of the northern hemisphere, consisting of 23 stars, according to Tycho, 40 according to Hevelius, and 66 in the Britannic Catalogue. This constellation is represented by the figure of an old man, in a posture somewhat like sitting, with a goat and her kids in his left hand, and a bridle in his right. AURORA borealis, or Aurora septemtrionulis, in physiology, the northern dawn or light, sometimes called streamers, is an extraordinary meteor, or luminous appearance, shewing itself in the night-time in the northern part of the heavens: and most usually in frosty weather. It is usually of a reddish colour, inclining to yellow, and sends out frequent corruscations of pale light, which seem to rise from the horizon in a pyramidal undulating form, and shoot with great velocity up to the zenith. The aurora borealis appears frequently in form of an arch, chiefly in the spring and autumn, after a dry year. The arch is partly bright, partly dark, but generally transparent; and the matter of which it consists is also found to have no effect on the rays of light which pass through it. Dr. Hamilton observes, that he could lainly discern the smallest speck in the Pleiades through the density of those clouds which formed the aurora borealis in 1763, without the least diminution of its splendour, or increase of twinkling. This kind of meteor, which is more uncommon as we approach towards the equator, is almost constant during the long winter, and appears with the greatest lustre in the polar regions. In the Shetland isles, the “merry dancers,” as the northern lights are there called, are the constant attendants of clear evenings, and afford great relief amidst the gloom of the long winter nights. They commonly appear at twilight, near the horizon, of a dun colour, approaching to yellow; they sometimes continue in that state for several hours, without any perceptible motion; and afterwards they break out into streams of stronger light, spreading into columns, and altering slowly into 10,000 different shapes, and varying

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