guish a contrary direction in the motion of the waters. Between the tropics, especially from the coast of Senegal to the Caribbean sea, the general current, that which was earliest known to mariners, flows constantly from east to west. This is called the equinoctial current. Its mean rapidity, corresponding to different latitudes, is the same in the Atlantic and Southern oceans, and may be estimated at 9 or 10 miles in 24 hours; consequently from 59 to 65 hundredths of a foot every second of time." This great observer also says, "In comparing the observations which I had occasion to make in the two hemispheres, with those which are laid down in the Voyages of Cook, la Perouse, d'Entrecasteaux, Vancouver, Macartney, Krusenstern and Marchand, I found that the swiftness of the general current of the tropics varies from to 18 miles in 24 hours, or from one third of a foot to one and two tenths per second." The western equinoctial current is felt, though feebly, as high as 28° N. lat., and about as far south, though it must be in excess along the equator. The eastern salient point of South America being in upwards of 6° S. lat., the great mass of ocean flood is unequally divided. South from cape St. Roque, the current is turned down the coast of South America, and, between 30° and 40° S. lat., reacts towards Africa. North from cape St. Roque, the coast of South America bends to a general course of N. 62 W., and, with the Caribbean sea and the gulf of Mexico, maintains that direction to the mouth of the Rio Grande del Norte, 2560 miles. Along this coast, the equinoctial current is inflected north ward, and augmented by constant accumulations from the east; the whole body pouring through the various inlets between the Windward islands of the West Indies into the Caribbean sea, and thence, between Cuba and Yucatan, into the gulf of Mexico. In the latter reservoir, it has reached its utmost elevation, and again rushes out into the A. through the Cuba and Bahama or Florida channel, and, sweeping along the coast of the U. States and Nova Scotia, to about 50° N. lat., meets the Arctic currents from Davis's straits, and, from the Northern Atlantic ocean, is turned towards Europe and the north-west of Africa, and is finally merged in its original source within the tropics. To this oceanic river has been given the name of gulf-stream. It is the second most extensive and much the most strongly marked whirlpool on

the globe, having an outline of about 15,000 miles. The mean notion of the gulf-stream is, no doubt, changeable, even at the same points. The time of its periodical revolution is about 2 years, and the maximum of motion in the Bahama channel. Humboldt notices this phenomenon thus:-"In the Florida channel, I observed, in the month of May, 1804. in the 26th and 27th degrees of latitude, a celerity of 80 miles in 24 hours, or 5 feer every second, though at this period the north wind blew with great violence. At the end of the gulf of Florida, in the parallel of cape Cannaveral, the gulf-stream, or current of Florida, runs to the N. E. Its rapidity resembles that of a torrent, and is sometimes five miles an hour." (For further information on this subject, see the article Current, and also Darby's View of the United States, Philadelphia, 1828.) -Humboldt endeavored to ascertain the comparative height of the waters of this ocean along its shores, and that of the Pacific on the opposite side of the isthmus, taking the level of the gulf of Mexico as a standard. He found the surface of the former to be 6 or 7 metres higher than that of the latter (19 or 22 feet, English measure). The depth of the A. is also extremely various, in many places being wholly beyond the power of man to fathom. Captain Scoresby, in the Greenland sea, in 1817, plumbed to the greatest known depth which a line has reached, i. c. 7200 feet. Many parts of this ocean, however, are thought to be much deeper. The saltness and specific gravity of the A. differ in various parts, and gradually diminish from the equator to the poles. In the neighborhood of the British isles, the salt has been stated at

th of the weight of the water; and, according to doctor Thompson, the proportion of saline contents does not appear to differ much, whatever may be the latitude in which the water is examined. The variation resulting from all the observations of Pages, Phipps and Baumè, is from 0.0451 to 0.35 saline matter. The temperature of the A. is highest between 5° 45′ and 6° 15′ N. lat., where it has been found, by actual observation, to vary from about 82° 5' to 84° 5' of Fahrenheit. Peron and Humboldt give several interesting results of their observations. The currents and the masses of ice which go from the north, in the general current, to the equator, change the temperature of the water very much. Fragments of these icebergs occasionally reach the 40th degree of latitude. In the months of June

and July, they add much to the danger of a passage between North America and England. We do not know that there exists an exact comparison of the natural history of the A. with that of other

oceans.

ATLANTIDES; pillars, in the form of a man, used in building, to support a projection or a cornice. (See Caryatides.)

ATLANTIS; among the ancients, the name of an island in the Atlantic, of which vague accounts had been received from ships which had ventured into the ocean. Their descriptions of its situation were very indefinite, and, as they placed it in a spot where afterwards no island was found, it was supposed that it had sunk. But some persons imagine that Phoenician or Carthaginian merchantships (as we know happened to a Portuguese ship in the time of Columbus), being driven out of their course by storms and currents, were forced over to the American coasts, from which they after wards fortunately returned to their country; and that, therefore, the island of A. mentioned by Plato, as well as the great nameless island spoken of by Diodorus, Pliny and Arnobius, was nothing more than what is now called America. The most distinct account of the island of A. is in Plato's Timæus. (See Atlantica.)

ATLAS; a chain of mountains which extends over a large part of Northern Africa. The Greater A. runs through the kingdom of Morocco, as far south as Sahara, and is more than 11,000 feet high. The Lesser A. extends from Morocco, towards the N. E., to the northern coast. -The mythology of the Greeks assigned this mountain to a Titan, son of Japetus and Clymene. Jupiter, the conqueror of the Titans, condemned him to bear the vault of heaven; which fable arose from his lofty stature. He was endowed with wisdom, and later accounts ascribe to him much knowledge, particularly of astronomy. By Pleione, the daughter of Oceanus, he had seven daughters, who, under the name of Pleiades (called, likewise, after their father, Atlantides), shone in the heavens. According to some, he was also the father of the Hyades. Atlas, in anatomy, is the name of the first vertebra of the neck, which supports the head. Atlas, in commerce; a silk cloth manufactured in the East Indies. The manufacture is admirable, and, as yet, inimitable by Europeans; yet it has not that lustre, which the French know how to give to their silk stuffs.-Atlas; a name

given to collections of maps and charts; so called from the giant who supported heaven. This name was first used to signify a geographical system, by Gerard Mercator, in the 16th century.

ATMOSPHERE; commonly, the air in which our earth appears to swim ; but, in the widest sense, it is that mass of thin, elastic fluid, with which any body is com pletely surrounded. Hence we speak of an atmosphere of the sun, of the moon, of the planets, of electric and magnetic bodies, &c., the existence of which may not be fully proved, but is more or less probable. It is certain that our earth has an atmosphere, by which, according to the preceding definition, we understand the surrounding body of air and vapor. By means of its weight, the air is inseparably connected with the earth, and presses on it according to the laws of heavy, elastic fluids. Its whole pressure is equal to its weight, and, like that of all other heavy, elastic fluids, is exerted equally on all sides. If, now, by any circumstance, a stronger pressure is exerted on one side, certain phenomena are observed, which continue till the equilibrium is restored. Thus, for instance, water ascends, in the bore of a pump, above its general level, as soon as a vacuum is made between it and the piston, which is drawn up. The cause of this is the disturbance of the equilibrium, since the air without the bore presses on the water without, while no air is present within. By means of this pressure, if the bore is long enough, the water may be raised to the height of 32 feet. This is the weight with which the atmosphere presses on the earth, and which is equal to the pressure of an ocean 32 feet deep, spread over the whole earth. Hence it follows, that, at 28 inches barometrical height, the atmosphere presses with a weight of 32,440 pounds on the human body, estimated at 15 square feet. The man does not perceive this pressure, because the air entirely surrounds him, and is, besides, within him. On account of its elasticity, it presses in every direction, even from within the man outwards, and consequently counterbalances the air spread over the body. That the atmosphere has not a uniform density, may be inferred from this, that the lower strata of the air have to support the weight of the upper ones, on which account they must become more compressed and denser. Ac cording to the law of Mariotte, the density of the atmosphere diminishes in geomet rical, while the height increases in arith

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metical progression. This law may not hold at the extreme limits of the atmosphere, because the air at that height, free from all pressure, must be completely in its natural state. The height of the atmosphere has been estimated, by natural philosophers, at from 30 to 40 miles partly from the pressure which it exerts, partly from the twilight; since it is to be supposed, that the air, as far as it reflects light or receives illumination, belongs to our planet. Delambre, however (Astronomie, vol. 3, p. 337), considers this height to be almost 46 miles, which, remarkably enough, Kepler has mentioned in the Cap. Astr., p. 73. In respect to its form, the atmosphere may be considered as a spheroid, elevated at the equator, on account of the diurnal motion of the earth, and also on account of the great rarefaction of the air by the sun's rays, which there exert a powerful influence. The constituent parts of the earth's atmosphere are nitrogen and oxygen, which are found every where, and at all times, nearly in the proportion 76: 23. Beside these, there is a small portion of carbonic acid, a variable portion of aqueous vapor, and a very small, indefinite quantity of hydrogen. (See Gas.) It also contains, in the form of vapor, a multitude of adventitious substances, in those injurious mixtures known under the name miasmata, the nature of which can hardly be investigated. As to the manner in which these different ingredients are united, various hypotheses have been formed, of which that of Dalton, which denies a chemical mixture, is one of the most cel ebrated, but also the most opposed. (For what has been written upon the atmosphere, see the article Atmosphere, in the new edition of Gehler's Dictionary of Natural Philosophy, 1 vol., Leipsic, 1825. De Luc's Recherches sur les Modifications de l'Atmosphère, 2 vols. 4to., Geneva, 1772 (in German, Leipsic, 1776-78), still continues to be held in high esteem. See the section d'Atmosphère, in Biot's Traité d'Astronomie Physique, 2d ed., Paris, 1810, 3 vols. On the atmosphere of the sun, moon and the other planets, see the respective articles. See, also, Air.)

ATOMS; according to the hypothesis of some philosophers, the primary parts of elementary matter not any further divisible. Moschus of Sidon, who is said to have lived before the Trojan war, taught, as we are told, that the original matter is composed of small, indivisible lodies. Leucippus (510 B. C.) established A system respecting the origin of the

world, resting on the mixture of atoms, in which chance governed, in opposition to the immaterial system of the Eleatics, who contended, that whatever existed was only one being, and that all apparent changes in the universe are mere illusions of sense. Democritus and Epicurus extended this system: the latter, particularly, made many additions to it. Lucretius, and, among the moderns, Gassendi, have illustrated the doctrine of Epicurus. Descartes formed from this his system of the vortices. Newton and Boerhaave supposed that the original matter consists of hard, ponderable, impenetrable, inactive and immutable particles, from the variety in the composition of which, the variety of bodies originates. A system founded on the theory of atoms is called atomic, e. g., that of le Sage; sometimes it is also called corpuscular philosophy, and is opposed to the dynamic theory. (See this article.) In Germany, the theory of atoms finds very few adherents: it is generally thought, in that country, a gross conception of the universe, and a very unsatisfactory one, as it only removes the question respecting the nature of matter one step farther. In France and England, the number of believers in it is greater.

ATOOI, or ATTOWA, or ATTOWAY, or Towi; one of the Sandwich islands, in the Pacific ocean; about 30 miles in length from E. to W., according to some; others make it 800 miles in circumfer-. ence. It has a good road and anchoringplace on the S. W. side of the island, called Wymoa. It is supposed to contain 12,000 inhabitants. The natives make canoes of fine workmanship. Some of them, from the frequent visits of British and American navigators, are able to converse in English. Several Europeans reside here. Lon. 159° 40′ W.; lat. 21° 57! N. (See Sandwich Islands.)

ATREBATES; the ancient inhabitants of Gallia Belgica, who possessed that part of Gaul afterwards called Artois. A colony of them settled in Britain. Cæsar mentions them as one of the nations confederated against him, and as having engaged to furnish 15,000 troops to the allied army. The Atrebates, or Atrebatii, in Britain, resided next to the Bibroci in a part of Berkshire and Oxfordshire. They were one of the tribes which submitted to Cæsar.

ned to Eurystheus, with whose daughter, Erope, A. united himself, and, after the death of his father-in-law, became king of Mycene. Thyestes, yielding to an unlawful passion for the wife of his brother, dishonored his bed, and had two sons by her. A., after the discovery of this injury, banished Thyestes with his sons. Thining for revenge, Thyestes conveyed away secretly a son of his brother, and instigated him to murder his own father. This design was discovered, and the youth, whom A. thought to be the son of his brother, was put to death. Too late did the unhappy father perceive his mistake. A horrible revenge was necessary to give him consolation. He pretended to be reconciled to Thyestes, and invited him, with his two sons, to a feast, and, after he had caused the latter to be secretly slain, he placed a dish made of their flesh before Thyestes, and, when he had finished eating, brought the bones of his sons, and showed him, with a scornful smile, the dreadful revenge which he had taken. At this spectacle, the poets say, the sun turned back in his course, in order not to throw light upon such a horrible deed.

ATRIDES. (See Agamemnon.) ATRIP (trepor, Fr.; trippen, Dutch) is applied indifferently to the anchor or to the sails. The anchor is atrip (derangée), when it is drawn out of the ground in a perpendicular direction, either by the cable or buoy-rope. The top-sails are said to be atrip, when they are hoisted up to the mast-head, or to their utmost extent.

ATROPHY is a deficient nourishment of the body. There are many diseases in which the body becomes daily more lean and emaciated, appears deprived of its common nourishment, and, for that reason, of its common strength. It is only, therefore, in those cases in which the emaciation constantly increases, that it constitutes a peculiar disease; for when it is merely a symptom of other common diseases, it ceases with the disease, as being merely a consequence of great evacuations, or of the diminished usefulness or imperfect digestion of the nourishment received. But, when emaciation or atrophy constitutes a disease by itself, It depends upon causes peculiar to this state of the system. These causes are, permanent, oppressive and exhausting passions, organic disease, a want of proper food or of pure air, exhausting diseases, as nervous or malignant fevers, suppura tions in important organs, as the lungs, the liver, &c. Copious evacuations of

blood, saliva, semen, &c. are also apt to produce this disease, and, on this account, lying-in women, and nurses who are of slender constitution, and those who are too much addicted to venery, are often the subjects of this complaint. This state of the system is also sometimes produced by poisons, e. g., arsenic, mercury, lead, in miners, painters, gilders, &c. A species of atrophy takes place in old people, in whom an entire loss of strength and flesh brings on a termination of life without the occurrence of any positive disorder. It is known as the marasmus senilis, or atrophy of old people. Atrophy is of frequent occurrence, in infancy, as a consequence of improper, unwholesome food, exposure to cold, damp or impure air, &c., producing a superabundance of mucus in the bowels, worms, obstructions of the mesenteric glands, followed by extreme emaciation, which state of things is often fatal, although the efforts of the physician are sometimes successful, when all the causes of the disease have been previously removed. A local state of the same kind is sometimes produced in single limbs, by palsies, or the pressure of tumors upon the nerves of the limb, &c., and is generally curable by removing the cause.

ATROPOS; one of the Fates. (q. v.)

ATTACCA, Italian (attach), signifies, in music, that a passage is to follow another immediately; e. g., attacca allegro.

ATTACHMENT denotes the apprehending a person, or seizing a thing, in virtue of a writ issuing from a court. An attachment of the person is more usually called an arrest. In respect to property, the word attachment more frequently refers to an arrest of it on mesne process, or before a judgment of court. In some of the U. States, a creditor may previously attach another person's property, real or personal, to satisfy the judgment he may recover: in other states, no such previous attachment can ordinarily be made, and is permitted only in case of absconding debtors, or other particularly excepted cases. And the more general and prevailing rule throughout the world is, that the property of a person can be seized only in pursuance of a judicial order or decree, made upon testimony being produced, and the party heard; and be tween a creditor and debtor, the more general and almost universal rule is, that the creditor cannot seize the goods or property of his alleged debtor until the debt is established by the proceedings of a judicial tribunal. In regard to the per

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son, attachments or arrests are made for a variety of causes, and, among others, for debt. But, in respect to an arrest of the person, as well as that of property, the laws of most countries do not permit the person of any citizen to be seized and imprisoned without a decree or judginent of a court directly authorizing the arrest. But in some of the U. States, any creditor to the amount of five dollars, or some other amount, greater or smaller, may arrest the person of his debtor, at the commencement of the process against him, in order that the creditor may have his body to levy execution upon, when the debt shall be established by a judicial decree or judgment. But attachment of the person for this cause is not permitted by the laws of most countries, except in cases of the apprehended absconding of the debtor; this being an exception to the rule most generally adopted, which is, that the creditor first establishes his debt, and gets judgment and execution upon it, before he can use it as an instrument for violating the personal liberty of his debtor. In cases of alleged crime, the person of the accused party is seized, and he is imprisoned, or compelled to give bail by the laws of all countries; but he is most generally first taken before a magistrate, and permitted to show cause against being imprisoned, or required to give bail.-Another cause of attachment is, the defendant's not appearing at court, after being summoned by subpoena (an order of court prescribing a penalty in case of disobedience) out of a court of chancery. His not obeying is considered to be a contempt of the court, which thereupon or ders him to be arrested, and brought into court. But attachment for this cause is not made in a court of law; for if the defendant, being summoned, does not appear, on being called in court, his default is noted, and the court proceeds to give judgment against him, upon such testimony as the plaintiff may produce. One reason of this distinction between a court of equity and a court of law is, that the presence and agency of the defendant are requisite, in many equity cases, in order to carry into effect the judgment of the court; as when the court decrees the specific execution of an agreement, or the rendering of an account, or the disclosure of facts by the defendant upon his oath. Attachments are issued by courts for various other contempts, as against an officer of a court for abusing the process of the court, e. g., 1 he refuse to execute it without a bribe

from a party; against a witness who re fuses to appear when summoned for the purpose of giving testimony, or who refuses to testify, after he has appeared, before a court of law or a grand jury . against any person, whether an officer of the court, a party, witness, or mere bystander, for disorderly conduct in the presence of the court, whereby its proceedings are disturbed and the administration of justice interrupted; for attempting to corrupt a juryman, or forcibly detain a witness who is summoned to testify in a case; for publishing an account of the proceedings of the court while a cause is pending, in such a manner that the minds of the judges or jurors may be prejudiced by such publication; for obstructing the service of any writ or process of the court; for taking out an execution where there is no judgment; and, in general, an attachment lies against any person who directly obstructs or 'interferes with the regular administration of justice. It lies against the judges of an inferior court who proceed in a case con trary to the order of a superior court.

ATTACHMENT, FOREIGN, is the attachment, by a creditor, of a debt due to his debtor from a third person; called foreign attachment, from its being one mode of securing debts due from foreigners. In Scotland, it is called assisting the debt. In London, the process is called a garnishment, or warning, the person summoned being the garnishee. The same process is, in some of the U. States, called the trustee process, and the person summoned is called the trustee, on the supposition of his having in his hands and possession, or being intrusted with, the money or goods of the principal debtor. The general rule, as to arresting debts due from third persons, by foreign attachment, is, that only absolute debts can be so attached, not the claims which the principal debtor may have against the garnishee, or supposed trustee, for damages on account of trespasses and wrongs done to him by the garnishee or supposed trustee. As the process is instituted to recover a supposed debt due to the plaintiff from the principal defendant, by obtaining satisfaction of a debtor of that defendant, he must have notice, and oe made a party to the suit, and have an opportunity to dispute the demand of the plaintiff; and the law, in some instances at least, allows the garnishee or trustee, if he be really a debtor to the principal defendant, to take upon himself the defence against the plaintiff's demand.