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the numerous pilgrims by which they are occasionally visited, and on the sums collected by their mendicant brethren in other parts. They pay an annual contribution to the Porte. No females are admitted within this peninsula; and a market held weekly within its limits, and resorted to by the country people, presents the singular spectacle of a market without noise, and a crowd without a woman!

Most of the monasteries possess considerable collections of manuscripts, and it was long a prevalent opinion that some of the lost treasures of ancient genius might be recovered, were a diligent search made in the monasteries of Mount Athos, In 1801, however, they were thoroughly explored by Dr. Carlyle, and, with the exception of a copy of the Illiad and Odyssey, a few of the edited plays of the different tragedians, a copy of Pindar and Hesiod. the Orations of Demosthenes and Eschines, parts of Aristotle, and copies of Philo and Josephus, he did not meet with any thing that could be called classical! There were some valuable MSS. of the New Testament, but none so old by centuries as the Codex Alexandrinus or MS. of Beza. Polemical divinity, and lives of the saints, formed the great bulk of the libraries.

The monasteries suffered severely from the exactions of the Turks during the Greek revolution. The entire population of the peninsula was estimated at about 6,000 in 1801; but at present it is probably rather under 3,000. (Walpole's Memoirs relating to Turkey, i. pp. 194-230.; Journal of the Geog. Society, vii. pp. 61–74.)

ATHY, an inl. town of Ireland. co. Kildare, prov. Leinster, on the Barrow, 38 m. S.W. Dublin. Its ancient name was Athlegar, "the western ford." From its position on the border of the English pale, and on a ford of the river, it has been a frequent scene of conflict. In 1308 it was plundered by the Irish, and burnt by Edward Bruce in 1315. A fort, built about 1506, to guard the pass of the river, was occupied in 1648 by Owen Roe O'Neal, on the part of the Irish, but in 1650 it surrendered to the parliamentary forces. Pop. in 1821, 3,693; in 1831, 4,494; in 1834, 4,615; of whom 780 were of the E. church, 20 Prot. dis., and 3,815 R. Cath. The two portions into which the town is divided by the Barrow, are connected by a bridge of five arches, thus forming one continuous main street, whence several lesser avenues diverge. There is a par. church, a plain building; a spacious R. Cath. chapel, with a Presbyterian and a Methodist meeting-house. Adjoining the town is a small chapel, an ancient cemetery, and a small Dominican monastery. Besides the parochial school, which instructs about 100 children, there are two others supported by voluntary subscriptions, in which 400 boys and 100 girls are instructed. There is also a dispensary and a poor fund. It is a chief constabulary station, and has a small cavalry barrack. By a charter of 11 James I., the corporation consists of a sovereign, two bailiffs, and 12 burgesses. Previously to the Union the borough sent two ms. to the Irish parliament. The summer assizes for the county are held here, as are general sessions of the peace in January and June, and petty sessions every Tuesday. The borough courts are now disused, except one called the curl court, in which the sovereign decides pleas of debt under 2. Irish currency, on the first Monday in every month. The county gaol is near the town: it is built on the radiating principle, and is provided with 32 sleeping, and 3 solitary cells. The committals to it in 1837 were 90. The sentences were,-death, none; transportation for life, 6; for 7 years, 12; imprisonment for one year, 2; for 6 months or under, 29; fine or whipping, 7; liberated by acquittal, or want of prosecution, 34. The total expenditure for the year was 8402., being an average of 9. 7s. for each prisoner. The markets are held on Tuesdays and Saturdays; the fairs on 17 Mar., 25 Apr., 9 June, 25 July, 10 Oct., and 11 Dec. The modern consequence of the town is mainly derived from its being at the junction of a branch of the Grand Canal with the Barrow, and from the latter being made navigable to its embouchure. It has, in consequence, become a place of considerable commercial importance. The principal trade is in corn, of which large quantities are purchased, partly for mills on the Barrow, but chiefly for the Dublin market, to which city it is conveyed principally by the Grand Canal. Corn, butter, provisions, &c., are also sent down the Barrow to New Ross and Waterford; and timber and other articles, for the use of the adjoining districts, are imported by the same channel. The malting trade is in a flourishing state: duty was paid in 1835 on 11,016 bushels. The post-office revenue in 1830 was 4207.; in 1836, 520. Passengers are conveyed to Dublin by the Grand Canal by means of fly-boats. Cne of the mail-coach roads from Dublin to Cork passes through the town; and a caravan, carrying 8 passengers each trip, daily plies to Carlow. (Municipal and Railroad Reports, &c.)

ATINA, a town of Naples, prov. Terra di Lavoro, 12 m. S. E. Sora, near the Melfa, among some of the loftiest summits of the Apennines. Pop. 4,000. It has ■ cathedral, a convent, and an hospital; and was formerly

the seat of a bishopric, suppressed by Pope Eugene III. It is principally remarkable for its Cyclopean remains. This is one of the most ancient of the Italian cities; being, according to Virgil (En. lib.vii. 629.), a considerable town as early as the Trojan war. It was taken from the Samnites by the Romans, A U.C. 440. Cicero says it was a prefecture, and one of the most populous and distinguished in Italy. (Cic. pro Planco.) It received a colony from Rome during the reign of Nero. (Cramer's Ancient Italy, ii. p. 116.) ATLANTIC OCEAN. This is one of the great divisions of that watery expanse which covers more than three fourths of the surface of the globe. It lies between the Old and the New World, washing the E. shores of the Americas, and the W. shores of Europe and Africa, extending lengthwise from the Arctic to the Antarctic Seas. Where narrowest, between Greenland and Norway, it is about 930 m. across; but between N. Africa and Florida, where it attains to its maximum breadth, the distance from shore to shore exceeds 4,150 m. Though it comprises little more than a fifth part of the whole ocean, its shores form a more extended line of coast than those of all the other seas taken together. This arises from several extensive mediterranean seas, which enter deeply into the contiguous continents, being connected by straits with the N. Atlantic Ocean, and forming portions of it. Such are the Baltic and Mediterranean Sea in the Old Continent; and Hudson's and Baffin's Bays, and the Columbian Sea (Gulph of Mexico and Caribbean Sea), in the New World. And it is probably in some degree owing to the facilities afforded for commercial intercourse by these arms of the Atlantic, that the countries in their vicinity have made a greater and more early progress in civilisation than those of most other parts of the world.

To the same cause has also been ascribed the circumstance of the nations inhabiting the shores of the Atlantic having applied themselves peculiarly to navigation: they have not limited their activity in this branch of industry to the Atlantic, but navigate every other sea; and there is now no harbour, how remote soever, which is not regularly visited by their ships, with the exception of those to which a free access is denied, or which do not furnish any article of trade. The Atlantic Ocean has thus, as it were, become the most frequented highway of commercial nations, and has been more completely explored and examined than the other seas; and frequently repeated experiments have enabled rules to be laid down for the guidance of vessels traversing its different parts, in different seasons of the year, which give the greatest facility and security to its navigation. Those groups of islands which impede navigation, and render it comparatively difficult and dangerous, are much less numerous in the Atlantic than in most other seas. If, indeed, we except the chain of islands which separates the Columbian Sea from the Atlantic, and which, therefore, may be considered as forming part of the shores of the ocean, it can hardly be said that there exists any such group of islands between 500 N. lat. and 505 S. lat. The Azores, Canaries, and Cape de Verd Islands, as well as those of Guinea and the Bermudas, occupy a comparatively small space, and are easily avoided; and the two last-mentioned groups lie far from the common track of vessels. The Canaries, including Madeira, are frequently visited; being situated where it is usual for vessels to change the direction of their course.

The direction of the winds and currents is of special importance as affecting the performance of voyages; and to the more exact knowledge of their course and influence, as well as to other improvements in the art of navigation, is to be ascribed the fact that voyages are at present performed in nearly half the time they occupied only two centuries ago.

Winds. As the Atlantic Ocean, including the two Icy Seas at its extremities, extends from the Arctic to the Antarctic Pole, it is in parts subject to the perpetual or trade winds, in others to the variable winds; and along some of its coasts, between the tropics, the winds are subject to a regular change according to the seasons-or, in other words, monsoons are there prevalent.

The trade-winds do not extend beyond the 32nd parallel from the equator; sometimes they are not met with at a greater distance than 270 lat. The whole surface of the sea extending from these latitudes to the poles is the province of the variable winds. The latter blow in every season from all points of the compass; but, by long experience, it has been found that the W. winds prevail in both hemispheres. If a line be drawn in the direction of a meridian, it is estimated that the proportion between the winds blowing from the W. to those that come from the E. is as 9 to 5. This, at least, is the proportion in the N. hemisphere, where the estimate has been made with the greatest exactness. It is, besides, to be observed, that whilst the winds between the tropics and near them blow nearly always with the same degree of force, the variable winds vary extremely

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in this respect, blowing sometimes almost with the strength of hurricanes, and at other times sinking into dead calms.

The two trade-winds do not blow over the whole surface of the sea lying between the tropics. They are separated from each other by the region of calms. This region varies, according to the seasons, in extent; and does not always occupy the same part of the ocean. It is found to extend from a short distance off the shores of the Old Continent to a short distance off those of the New, but its breadth is very various. Sometimes it occupies not more than 3° of lat., and at other seasons up to 10. The most remarkable fact respecting this region is, that it does not extend equally on both sides the equator, but lies nearly the whole year round in the N. hemisphere. Only when the sun is near the tropic of Capricorn it passes the line, but never extends farther to the S. than 21. On the N. of the equator it advances, at certain seasons, even to the 14th or 15th deg. of lat. These changes in the extent and in the range in which the region of calms is met with, and in which the tradewinds blow, depend evidently on the position of the sun. When the sun is near the N. tropic, or retiring from it, especially in July, August, and September, the calms advance towards the N. even to the 14th and 15th deg. of lat.; and at the same time the S. trade-winds encroach considerably on the N. hemisphere, being met with as far as the 4th or 5th deg. of N. lat. Then the breadth of the region of calms is 100; but when the sun is near the S. tropic, or begins to retire from it, the S. tradewinds also recede farther S.; and in January, February, and March, the calms extend to the S. of the line, but only to a distance of from 10 to 24°. In this season the N. trade-wind advances to 2° N. lat., and the width of the region of calms is then narrowed to from 30 to 40 lat. The central line of the region of calms may be placed at about 50 or 540 lat.; and its mean breadth may extend over 50 or 50, or from 300 to 350 sea Continued calms reign in this region; and they would form an insuperable obstacle to the progress of vessels, were not the air daily agitated by a squall which occurs about 2 o'clock in the afternoon. At noon, a black and well-defined cloud appears near the horizon, which increases, and announces a violent thunder-storm; suddenly a wind arises, blows for a short time with great violence, sends down a few drops of rain; and after this tumult of the elements has lasted from to 1 hour, the calm returns. These short violent squalls are called tornados, and it is only by their means that the region of calms can be passed by vessels using sails; but it always proves a very tedious navigation.

m.

The northern trade-wind is subject to change, not only respecting the extent of sea over which, but also respecting the direction in which, it blows. When the sun advances in the N. hemisphere, it withdraws, as already seen, farther from the equator. It, also, blows over a wider range of sea, near the coasts of America, than at a short distance from the Old Continent. In the seas inclosing the Canary Islands, it is rarely met with at 300 lat., and often not before the 27th parallel is reached; here, therefore, its N. boundary may be fixed at 2810 N. lat. as a mean. On the W. borders of the ocean, however, near the coast of America, it extends farther N., even to 320 lat.; here its mean boundary may be fixed at 300 lat. In the neighbourhood of the Old Continent, this trade-wind blows from the N.E., but it declines more to the E. as it proceeds farther W. In the middle of the ocean it is E. N., and where it approaches the New Continent it blows from due E. This wind is somewhat changeable towards its N. boundary; sometimes violent N.E. winds are found to prevail between the 22d and 30th deg. of lat., and in the same parallels it is frequently very weak. But no navigation can be more pleasant than that with this tradewind. It is rather to be called a breeze than a wind; and is uniform, and never interrupted by squalls. The waves which are raised by it are low, and their swell gentle. Where this wind blows, the passage from the Old Continent to America may safely be effected in an open boat. Hence the Spaniards have called this part of the Atlantic Ocean the "Sea of the Ladies," Golfo de las Damas.

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The southern trade-wind differs from the northern in the greater extent of sea over which it blows, extending, as we previously observed, in summer, to 50 or even 60 to the N., and never receding farther to the S. of the equator than 20. It is, farther, much more regular, not being interrupted towards its S. boundary by other winds. Its direction near the Old Continent is, also, somewhat different; for here it blows parallel to the coast extending from the Cape of Good Hope to the Bight of Benin-that is, from the S. At a distance from the continent it becomes by degrees more easterly, and where it approaches America its direction is nearly due E. The meridian of 200 W. of Greenwich may be considered as the line of separation between the winds which blow more southerly or more easterly. To the E.]

of this line, the wind varies between S.S.W. and S.S.E.; but to the W. of it, between S.S.E. and S.S.W.

In some parts the trade-winds extend to the very shores of the continents; in others, a tract of sea lies between the trade-winds and the land in which a different wind is prevalent. Thus it is found, that in the sea between the N. trade-wind and the African coast, from the Canaries to the Cape de Verd Islands, the wind blows constantly from the W. This phenomenon is sufficiently explained by the peculiar nature of the Great African desert, the Sahara. Its surface, destitute of vegetation, and covered with loose sand, is heated by the sun to an excessive degree, and in consequence the superincumbent air is rarefied, and rises. Where this rarefied air comes into contact with the more dense air covering the surface of the sea, the latter expands over the desert; and this gives rise to a continual flow of air from W. to E.

Farther S., between the Cape de Verd Islands and Cape Mesurado (7° N. lat.), a kind of monsoon prevails, which, in certain places, blows to the distance of 200 m., and opposite Sierra Leone about 150 m., off shore. From September to June it proceeds from the N. or N.E., and in the rest of the year from S. W. Along the coast of Guinea, and in the Bight of Benin, the S. tradewind prevails nearly the whole year round; but its direction is a little changed, the wind blowing from the S.W. Between the Bight of Benin and 30° S. lat., the trade-wind blows to the very shores of the continent. On the other side of the Atlantic Ocean, along the coast of Brazil, a regular monsoon prevails. It proceeds, between September and March, from between N. E. and N.E. E.; and from March to September, from between E. N. to E.S.E. These winds blow with considerable force, and extend sometimes to a great distance from the shore, especially in the months of June and July. There are instances on record of its having been met with nearly as far as the middle of the

Atlantic.

N. of Cape S. Roque, the trade winds reach the very shores of the American continent and the West Indies. In these parts they seem even to extend over a considerable part of the continent itself; for the continual E. wind which blows over the plain of the river Amazon, to the very foot of the Andes, is with reason considered as a continuation of the trade-winds. The same may be said of the E. winds which blow over the plains watered by the Orinoco, where this wind is felt as far as Angostura, and at certain seasons still farther W.

Currents. We are less acquainted with the currents than with the winds. This arises partly from the diffculties in which the subject is naturally involved, and partly from the comparatively short time which has elapsed since they have attracted the attention of naviga

tors and naturalists.

Currents are to be distinguished from drift-water. By the latter expression, that motion of the water is understood, which is produced on the surface of the sea by perpetual or prevailing winds. By pushing continually the upper strata of the water towards that point to which they blow, they cause a slow motion of the water in that direction. Accordingly, we find that that part of the Atlantic Ocean, which is subject to the trade-wind, is in a continual motion towards the W.; which is most sensible in those regions which are always exposed to the trade-winds, and less so where they blow only in certain seasons. This kind of current is in most parts constant, but its flow very gentle. Its mean velocity is from 9 to 10 m. a day, and it is very favourable to navigation.

Other drift-currents are met with in those parts of the Atlantic, in which the wind changes with the seasons; as along the coast of Sierra Leone, and that of Brazil, S. of Cape S. Augustine. In the former the current runs, from September to June, S., and in the remainder of the year in a N. direction. Along the coasts of Brazil, the current, from September to March, runs in a S. direction, and from March to September, N.

Even in those parts of the Atlantic which are subject to a continual change of the wind, a drift-current is observable. We observed, that N. of 30° N. lat., and S. of 30 S. lat., in the region of the variable winds, the W. winds prevail, and in these parts of the ocean a W. current is perceived; but it is feeble, and manifests itself in the N. Atlantic only on the whole course of a voyage from Europe to America and backward, retarding the former and forwarding the latter. This driftcurrent seems to attain its greatest velocity S. of 300 S. lat.

Besides the drift-currents, the velocity of which is moderate, there are others of much greater force, called properly currents. Their origin is still involved in obscurity; but, from some facts, we may suppose that they are not formed on the surface of the water, but are of great depth, and in many parts, if not in all, extend to the very bottom of the sea. These currents cannot be compared with rivers; for they extend over such a portion of the surface of the sea, that if they were trans

ferred to the continent they would cover countries of
great extent.
In the Atlantic, these currents run across the ocean in
three places. The current crossing the Atlantic near
the line, is called the Equatorial current; it runs from
E. to W. The current, which, in a direction from W. to
E., traverses the N. Atlantic between 36° and 44°, bears
the name of the Gulph Stream; and that which runs in
the same direction, through the S. Atlantic, between 30°
and 40° S. lat., is named the S. Atlantic current.
Other currents run along the shores of both continents
between 40° N. lat. and 300 S. lat. Along the Old Con-
tinent they run towards the equator; but, on the shores
of America, they flow from the line towards the poles.
These latter kind of currents are intimately connected
with the equatorial current; but very slightly, if at all,
with the gulph stream or the S. current.

The Equatorial current may be supposed to have its origin in the Bight of Benin, on the W. shores of Africa, between the islands of Anno Bom and St. Thomas; whence it proceeds, in a W. direction, towards Capes S. Roque and Augustine, on the coast of Brazil. Its breadth is different in different parts. Near its origin it is not quite 3° of lat. across, about 160 m.; but, in its progress to the W., it increases considerably in width. Opposite Cape Palmas, its N. border is found at about 10 45 N. lat., but the S. reaches nearly to 50 S. lat.: thus its breadth extends here over more than 60 of lat., or upward of 360 nautical m. It attains its greatest breadth between 200 and 220 W. long., where it extends over 70 or 80 of lat., from 44° or 50 S. of the equator to 240 or 30 N. of it; here, consequently, it is 450 nautical m. across. A little farther W., between 220 and 230 W. long., it sends off a branch to the N.W.; and here it narrows to about 300 m., which breadth it probably preserves up to its division into two currents, opposite Capes S. Roque and S. Augustine; but that part of its course, which lies W. of 23 and 24° W. long., is somewhat declined towards the S. Its velocity varies likewise, not only in the different parts of its course, but also in different seasons; being much greater in summer than in winter. From Anno Bom to 100 W. long. it may run from 25 to 30 m. a day; but between 10 and 160 its velocity increases to from 44 to 80 m. at the end of June and the beginning of July; in the other summer month it is somewhat less; and, from October to March, very moderate, and sometimes very weak. Between 160 and 230 W. long., where it is commonly crossed by vessels, the rapidity of the current rises often to 45, 50, and even 60 m. per day; but its mean velocity may be fixed at about 30 m. That part of the current, between 230 and the coast of Brazil, is avoided by vessels, and its rapidity not exactly known; it seems rather to increase, and not to be affected by the seasons. The temperature of the water within the current is every where some degrees lower than that of the seas without the current. The whole length of this current, from S. Thomas to Cape S. Roque, amounts to upward of 2,500 sea m.

The portion of the equatorial current which branches off from the main stream between 220 and 230 W. long., and about 20 N. lat., is called the N. W. current. At the point of separation, it may be from 180 to 200 m. in width; farther N. it widens even to 300 m., but narrows again to 240 and less. Its velocity is not so great as that of the main equatorial current. In its S. part, as far as 100 N. lat., it may run 30 m. a day; but it afterwards slackens considerably; yet at all times it may be traced up to 180 N. lat., and commonly even to 250." In the N. part of its course it declines more to the N., till it is lost in the drift-current. It is not improbable that this current increases the velocity of the drift-current, which navigators have observed between 350 W. lat. and the island of Trinidad; and that the change in the direction of the drift-current, which here declines to the N. W., is also to be ascribed to the same

cause.

At a distance of about 300 m. from the coast of Brazil, extending between Capes S. Roque and S. Augustine, the equatorial current divides into two branches. That which continues to run along the N. coast of Brazil, turns at the mouth of the Amazon to the N., and proceeds along the shores of Guyana to the island of Trinidad, where it enters the Caribbean Sea. It is called the Guyana current, and the length of its course does not fall short of 1,500 m. Its velocity is greatest in summer and winter; and may, in the former, be about 30 m. a day at a mean. It enters the Caribbean Sea by the different straits which, S. of the island of Martinique, divide the smaller Antilles from one another and from the continent of S. America. In these straits, the currents setting into the Caribbean Sea are strong: that between Trinidad and Grenada runs from 1 to 14 m. per hour; less rapid is the current in the strait between S. Vincent and S. Lucia; and between the latter island and Martinique it runs not more than 21 m. per day. At | the Virgin Islands the flow of the water is only 8 or 10 m.

a day; and that is not more than the common rate at which the drift-current runs. In the Caribbean Sea the Guyana current terminates; for, in that sea, no perpetual current has been traced. It rather seems that the currents which exist there, depend on the winds, and change the direction of their course according to the seasons. The other current, which branches off from the equatorial current, opposite Cape S. Augustine in Brazil, is called the Brazil current, and runs to the S.W. along the shores of S. America, but does not in any part of its course approach near to them. From 8° S. lat., where it separates from the Guyana current, to 160 or 17° S. lat., the current has a considerable width, and runs about 20 m. or somewhat more a day. Its distance from the continent is no where less than 250 m. Farther S. it increases in breadth and velocity, and approaches at the same time nearer the continent. Opposite Cape Frio it runs about 30 m. a day, and is not more than 200 m. distant from the coast. As, however, from the last-mentioned cape the land falls back to the W., the current is soon found at 300 m. and more from the continent. By declining, by degrees, its course farther to the W., it approaches nearer; but never is found at a distance less than 250 m. Thus it continues to the mouth of the La Plata river, running all this way from 15 to 20 m. per day. It becomes weaker as it advances farther S.; but may be traced to the Straits of Magalhaens and Le Maire. In the space of sea which intervenes between this current and the coast, the changeable currents occur, noticed above among the currents depending on monsoons.

The Guyana and Brazil currents are those, with which the Equatorial current is connected on the shores of America. The currents with which this great sea-stream is united near the coast of the Old Continent, are the S. and the N. African currents. The S. African current seems to have its origin some degrees N. of the Cape of Good Hope. It appears, however, not to be connected with the Agulhas current, which is found at a short distance S. from the Cape, and which runs W. from the Indian into the Atlantic Ocean. Between 180 and 110 S. lat. exists a current running from S. to N. at a short distance from the coasts of Africa, but we are not acquainted either with its breadth or velocity; neither, however, appears to be considerable. Between 11° and the island of Anno Bom, the current runs in a N.W. by W. direction, at the rate of from 15 to 25 or even 30 m. a day, but seems to be of inconsiderable width. It increases in velocity at the mouth of the river Zaire, and in width at Cape Lopez; but soon afterwards merges into the Equatorial current.

The North-African current, which is also called the Guinea current from its terminating opposite the coast of Guinea, has its origin opposite the coast of France, between the southern shores of Ireland and Cape Finisterre in Spain. It is impossible to determine more precisely the place where it originates; but it is a fact well established by experience, that the whole body of water between the Peninsula and the Azores is in motion towards the S., the western part setting more southerly, and the eastern more to the S.E. Between Cape S. Vincent in Portugal, and Cape Cantin in Marocco, the motion is directed towards the Straits of Gibraltar; and this motion extends as far westward as 200 W. long. Between Cape Cantin and Cape Blanco the general direction of the current is along the coast, but it sets in nearly perpendicularly towards the shores. This portion of the current is about 300 m. across between Cape Cantin and Cape Bojador, but only from 150 to 180 between the last-mentioned Cape and Cape Blanco. Between Cape Blanco and Cape de Verd the current runs a little to the W. of S., approaching the general direction of the driftcurrent of the trade-winds. Near the Cape de Verd Islands the temperature of the water of the current is 80 lower than in those parts of the sea which lie beyond it. After passing Cape de Verd, the current turns S., and by degrees S. E. and S.S. E. Here it does not approach the shores of Africa; at least, between Cape de Verd and Cape Mesurado it is met with only at a distance of about 200 m. from the coast. The intermediate space is occupied by periodical currents, which run, from September to June, S. or S.W.; but in the remainder of the year, N.E. S. of Cape Mesurado it approaches the coast, and increases in velocity, running sometimes at the rate of 2 m. per hour; here its temperature is considerably increased, but still lower than that of the ocean at large. At Cape Palmas it turns entirely to the E.; and skirts the coast of Guinea until it disappears in the sea opposite the mouth of the Quorra, and in the Bay of Biafra, where it partly seems to mingle with the Equatorial current. With the N. African current another current is connected, which runs across the British Channel at its western extremity. It runs E. from Cape Finisterre along the S. shores of the Bay of Biscay; turns then to the N. and N. W., along the W. coast of France; and passing Ushant, it traverses the British and Irish Channels. At the Scilly Islands, which it touches with its eastern border, it is 60 m. across.

It then con

tinues to the southern shores of Ireland, W. of Carnsore Point; and hence turns to Cape Clear, where, after entering the ocean, it turns to the S. and S.E., and rejoins the N. African current. By this current vessels are frequently placed in danger near the Scilly Islands. With certain winds this current runs from 24 to 28 m. a day. We owe the exact knowledge of this current to the careful investigations of the late Major Rennel, and hence it has been called Rennel's current.

The Gulph stream which crosses the Atlantic between 36° and 44 N. lat., originates in the Gulph of Mexico. The water in this sea is set by two currents into a nearly circular motion; which seems to be the principal reason why it acquires such a high degree of temperature,--being 86 Fahr., whilst that of the ocean at large in the same lat. (25° N.) does not exceed 78° Fahr. The two currents, which put in motion perhaps three fourths of the water of the gulph, unite about 70 m. W. of the Havannah; and by this junction the Gulph stream is formed. It runs along the N. coast of the island of Cuba, eastward; but it is neither broad nor rapid at the entrance of the Straits of Florida at the Salt Kays, where it begins to run about 1 m. an hour. After entering the straits, its velocity increases to 24, 3, and occasionally 4 m. an hour. In the Narrows, however, between Cape Florida and the Bimini Islands (which belong to the Bahamas), where the strait is only 44 m. across, and the water-way is straitened by reefs and shoals to 35 m., it runs, in the month of August, 5 m. an hour; and at that rate commonly through the remainder of the strait up to Cape Cañaveral. Though the current has traversed, in this space, about 4° of lat., the temperature of its water is not sensibly diminished. From Cape Caflaveral (about 28° N. lat.) the gulph-stream runs first due N., and then nearly N.E., along the shores of the United States, up to Cape Hatteras (33° N. lat.). It increases gradually in width, and decreases in velocity. At Cape Hatteras it is from 72 to 75 m. across, and it runs only 34 m. per hour. The temperature of its water has sunk from 860 to 83°. In this part, the current runs not so close to the shores as in the Strait of Florida. Its N.W. edge is about 24 m. S.E. from Cape Hatteras. After passing this cape, the current increases still more rapidly in width, and diminishes gradually in velocity, Between Cape Hatteras and the banks of Nantucket and St. George (400 N. lat.), the general direction of the current continues to be from S. W. to N.E., though the W. edge runs nearly due N. At the Nantucket and S. George Banks it suddenly declines its course to the E., and brushing the S. extremity of the great bank of Newfoundland, it continues in that direction as far as 43° or 440 W. long., between 37° and 43° N. lat. Farther E. it bends to the S.E. and S.; and having inclosed the islands of Flores and Corvo, belonging to the group of the Azores, it is lost in the ocean. There are some instances on record of the warm water of the gulph stream having advanced to the very shores of Spain and Portugal. It is difficult to determine the width of the current where it runs across the Atlantic, because its warm water expands on both sides to a considerable distance, where no current has been traced. The strongest current is between 380 and 39° N. lat. ; and it is probable that the breadth of the whole current does not exceed 120 naut. m., though the warm water is found to be 200, 250, and even 320 m. across. Between 65° and 66° W. long. the strongest current runs from 55 to 56 m. a day; but 900 m. farther E., only from 30 to 33 m. In the neighbourhood of the Azores its mean rate does not exceed 10 m. a day. The temperature of its water decreases less rapidly. At the meridian of 6310 W. long., or 600 nautical m. from Cape Hatteras, the thermometer shows in summer 81°, or from 100 to 110 above the water of the sea under the same lat. At 73° long. its temperature is 750; and even at Corvo, not lower than 7210, or from 80 to 10° above the ocean. The length of the gulph stream from the Salt Kays to the S. of the Azores is upwards of 3,000 naut. m. It traverses from 190 to 20 of lat. (from 230 to 42° or 43°), and its temperature decreases only 1340 (from 860 to 7210). The sea which is traversed by it is subject to nearly continual gales; especially towards the outer edges of the current.

Nearly in the middle of the Atlantic the gulph stream is joined by the Arctic current, which originates beneath the immense masses of ice that surround the pole, and thence runs in a S. W. direction along the E. shores of Greenland, carrying with it a great number of icebergs, ice-fields, and ice-floes. Pressing these icy masses against the coast of Greenland, the current renders that coast inaccessible; but it prevents the ice from spreading over the North Sea, and from encumbering the shores of the British islands. At Cape Farewell the width of the current seems to be from 120 to 160 m., the ice-masses extending to such a distance from it. After passing Cape Farewell, the current bends to the N. and enters Davis's Strait, running along the western coast of Greenland up to the Polar Circle, where it crosses the strait to Cape Walsingham (about 66° N. lat.); hence it flows south- |

ward along Cumberland's Island to Frobisher's and Hudson's Straits. Opposite these straits it runs from 15 to 16 m. a day. Approaching Newfoundland, the current divides: one branch, running through the strait of Belle Isle, mixes with the waters brought down by the St. Lawrence; whilst the other skirts the E. shores of Newfoundland, where it passes between the great and the outer bank of Newfoundland (between 45° and 460 lat., and 46° and 47° long.), and at last joins the gulph stream between 44° and 47° W. long. The width of this current, probably, no where exceeds 200 m.; the temperature of its water is always considerably lower than that of the ocean, sometimes as much as 160 or 170.

The last current we have to notice, is the South Atlantic current, which traverses the ocean from E. to W. between 30° and 40° S. lat. It is not known whether this current be connected with the Brazil current, and we are only generally acquainted with the existence of a motion in the sea between the S. coasts of Brazil and the Cape of Good Hope. In the W. part of the Atlantic its velocity seems to be moderate; but it increases as the current advances farther E., and opposite the Cape it is very strong. It is met with at a distance of from 150 to 180 m. from the Cape; hence it flows in a straight line into the Indian Ocean, and traces of it are found 2,000 m. beyond the Cape. That space of sea which intervenes between this current and the Cape, is occupied by another current, which runs in an opposite direction; being formed in the Indian Ocean by two currents which descend on both sides the island of Madagascar, and unite between the first point of Natal and Cape Recife, about 33° S. lat. Passing the Cape of Good Hope, it enters the Atlantic as a current, running at the rate of from 1 or 14 m. an hour in a N. W. direction, and may be traced as far as 250 S. lat. This current is called the Agulhas current, from passing over the bank of that name at the S. extremity of Africa.

Tracks of Vessels. — In proportion as our knowledge of the prevailing winds and of the strength and direction of the currents has increased, the tracks have been fixed with more precision, which vessels should follow in sailing from or to a country lying on the shores of the Atlantic. In a few cases they follow the same route, whether outward or homeward bound; but in most cases they follow different routes. We shall notice a few of those which are most frequented.

1. Between Europe and the W. coast of N. America vessels keep clear of the gulph stream, sailing along its N. border, between 440 and 500 N. lat. If, in sailing from E. to W., they were to enter the gulph stream and to stem its current, they would be delayed in their course, perhaps, not less than a fortnight. If, in sailing from W. to E., they were to enter it, they, doubtless, would arrive four or five days sooner in Europe; but the vessels would suffer, from the continual gales which prevail within the borders of the stream, so muchdamage in wear and tear, that it hardly could be compensated by the gain of a few days. In sailing to the United States N. of the gulph stream, vessels have the advantage of a counter current, which runs from the Nantucket and St. George Banks to Chesapeak Bay, and perhaps to Cape Hatteras.

2. In sailing from Europe to the West Indies, and the countries S., W., and N. of the Columbian Sea, different tracks are followed, outward and homeward. In sailing from Europe, the trade-winds are taken advantage of. The vessels pass Madeira and the Canary Islands, and sail S. as far as 210 N. lat., where they are certain to find a constant trade-wind. In this course they must avoid approaching too near the coast of Africa between Cape Nun and Cape Blanco, because the N. African current sets in towards the shores of the Sahara, and the winds blow continually from the sea towards the land. Many navigators who hoped to make the island of Teneriffe, according to their dead reckoning, have been carried so far to the E., that they have been cast on these inhospitable shores, where most of them have perished. Between 1790 and 1805, not less than 30 vessels are known to have been thus lost; and it is supposed that many others had the same fate, without its being known. Having got a constant trade-wind at 21° N. lat., the vessels sail W., and enter the Columbian Sea commonly by one of the straits lying between the islands of Martinique and Trinidad.

In sailing homeward ships sometimes go through the Mona (between Puerto Rico and Haïti) and windward (between Haiti and Cuba) passages; but more commonly they pass round the island of Cuba on the W., and sail through the Straits of Florida. As soon as they have got clear of the strait, they sail E. to get clear of the gulph stream. They then direct their course across the Atlantic, S. of the Bermudas, till they come into the longitude of the island of Flores. They then sail N., either passing between Flores and the other Azores, or to the E. of the group.

3. In sailing from Europe to the coast of Guyana (Demarara, Surinam, and Cayenne), and to those pro

vinces of Brazil which are situated W. of Cape St. | Roque, ships go S. till they meet the trade-wind, and then shape their course to the place of destination, but keeping a few degrees farther to the E.; for, on approaching the New Continent, they meet the Guyana current, which carries them W. If, therefore, they make land somewhat too far to the W., they find it very difficult to attain their place of destination, having to bear up against the current.

In returning to Europe, the vessels sail along the shores of America, where they are favoured by the Guyana current, as far as the island of Trinidad. Then they keep to the windward of the Antilles, till they get into the variable winds, where they follow the track of the vessels returning from the W. Indies.

4. Sailing from Europe to S. America, S. of Cape St. Roque, ships have to pass through the region of calms, and to traverse the Equatorial current. The first retards their progress, and the second carries them forcibly to the W. If they cut the equatorial line W. of 255 W. long., they cannot make Cape St. Roque, and fall in with the Guyana current, which carries them still farther W., and along the N. coast of Brazil. Then they can only get back to Cape St. Roque by a toilsome voyage of many days, and even weeks. To avoid this, vessels traverse the line between 180 and 23° W. long. Having done this, they are assisted by the Brazil current in making, with ease, any part of the coast they please. Vessels homeward bound from this coast take different tracts, according to the seasons. From March to September, when the monsoons blow, and the currents run, from S. to N., between the Brazil current and the continent of S. America, they sail along the shores, till, at Cape St. Roque, they meet the Guyana current; and then they follow the track of the vessels returning from Guyana to Europe. But, from September to March, the periodical winds and currents blow and run from E. to S. W., in the direction of the Brazil current. Ships then sail across the currents, and try to get into the middle of the Atlantic, where they follow the track of the vessels returning from the East Indies.

5. In sailing to the East Indies, it is now the general practice to avoid the numerous difficulties met with in navigating along the coasts of Africa, S. of the equator, and to follow the tracks of the vessels bound to Brazil. Afterwards, the vessels proceed along the coast of S. America to 320 or 33° S. lat., where they get out of the range of the S. E. trade-winds, and are certain to meet with the S. Atlantic current, which carries them eastward. They do not touch at the Cape of Good Hope, but follow the current until they enter the Indian Ocean.

In returning from the East Indies to Europe, vessels enter the Agulhas current near Madagascar, and are carried by it to the Cape of Good Hope, where they commonly stop for some time. From the Cape, the same current takes them by its N. W. course to the middle of the Atlantic. They then shape their course N., so as to traverse the line between 22 and 240 W. long., where they meet the N.W. current, which takes them to 200 or 250 N. lat.; whence they proceed to the Azores.

Ice. Both extremities of the Atlantic Ocean are invaded by great masses of ice. They either have been detached from the enormous masses, which inclose the poles to a great distance, or from those countries, which are situated so near the poles, that their coasts are covered with ice for the greater part of the year. In the N. seas, the ice consists of icebergs, ice-fields, and icefloes. The icebergs are enormous masses of ice, sometimes several hundred and even thousand yards long and broad; their summits being, in some cases, 100 ft. and more above the level of the sea, though only a seventh part of the whole mass rises above it. They are properly glaciers, formed along the high and snow-covered coast of Greenland, and which have afterwards been precipitated into the sea. The ice-fields and ice-floes are considered as having been detached from the ice surrounding the pole. This ice is commonly of the thickness of from 20 to 30 ft., and rises from 3 to 4 ft. above the sea. These masses are called fields, whenever they are so extensive that their limits cannot be discovered from the mast-head; and floes, when their extent may be overlooked from it. In the S. Atlantic only, fields and floes are found, icebergs never having been met with. It is further worth remarking, that the ice advances much nearer to the N. than to the S. tropic. The ice-floes at Cape Horn are far from being numerous; and Capt. Weddell says, that at 55° 20' S. lat., there is no fear of falling in with ice. In the N. hemisphere, we always find great ice-masses at some distance from the E. shores of Newfoundland from January to May and June; and icebergs are annually seen grounded on the Great Bank. It even sometimes happens that icebergs are met with in the gulph stream, 400 N. lat. and 320 W. long., as was the case in 1817. Miscellaneous Remarks. Fish seem to be much more plentiful in the seas near the arctic, than in those surrounding the antarctic, pole. This is probably to be

accounted for by the greater number and greater extent of banks found in the N. seas, and these, besides, wash a far greater extent of shores, which many species of fish resort to in quest of food. Another remarkable fact is, that the seas near the equator, and, in general, those lying in lower latitudes, are much richer in species than the N. parts of the ocean; but that, in the latter, the number of individuals belonging to each species is far greater. Hence we find that the most extensive fisheries are those, which are carried on to the N. of 450 N. lat.; as the cod fisheries on the Great Bank of Newfoundland, and at the Laffoden Islands, the whale fishery at Spitzbergen and on both sides of Greenland, the herring fishery along the coasts of Great Britain, and the pilchard fishery in the British Channel. The most important fisheries S. of 45°, if we except the whale fishery near the S. pole, seem to be that in the Caribbean Sea along the coasts of Venezuela, and that which the inhabitants of the Canary Islands carry on in the sea surrounding Cape Blanco in Africa.

The temperature of the water is greater in the N. than in the S. hemisphere. In the seas N. of the Equatorial current, the thermometer indicates 80° or 81°, and S. of it 770 and 78°, at the time when the sun approaches the line. This difference may, perhaps, be satisfactorily accounted for by the sun's remaining annually seven days longer to the N. than to the S. of the equator. The specific gravity and saltness of the sea-water is, doubtless, greater near the equator, than in the vicinity of the poles; but the experiments which have been made to determine the exact difference, have given such different results, that we must still consider this question as undecided. According to Capt. Scoresby, the specific gravity of the sea-water near the coasts of Greenland varies between 1·0259 and 1·0270. Between the tropics, some have found it 10300, or nearly this much; and near the equator, even 1.0578, but the last statement is, with reason, regarded as doubtful.

In a part of the Atlantic, the gulph-weed, or fucus natans, occurs in great quantities. This region extends nearly across the whole ocean, beginning on the E. at the 30th meridian, and terminating on the W. in the sea washing the E. side of the Bahama Bank. In width, it occupies the whole space between 200 and 360 N. lat.; but the whole extent of the surface between these lines is not equally crowded with weed. The most crowded part extends between 300 and 320 W. long. ; where, in the neighbourhood of the island of Flores, one of the Azores,-it forms first only a small stripe; but farther to the S. expands to a great width. In this part of the Atlantic, which is called by the Portuguese, Mar de Sargasso (Weedy Sea), the fucus covers, like a mantle, far and wide, the surface of the sea, extending from N. to S. more than 1,200 m. Another part of the sea, covered with fucus in a very crowded state, occurs between the meridians of 700 and 720, and the parallels of 220 and 260, towards the W. end of the region. The sea lying be tween these two crowded districts, is, in some parts, only lightly strewed with sea-weeds; but, in others, it occurs in dense masses.

Many conjectures have been formed as to the origin of the name given to this great sea. Of these, the most probable seems to be that which derives it from Mount Atlas. Being first navigated by Phoenician and Carthaginian adventurers, they would naturally designate it by the most conspicuous feature in the limited space with which they were acquainted; and would, therefore, call it Mare Atlanticum, or Sea of Atlas.

ATLAS (MOUNT), according to Herodotus, was a single isolated mountain of great elevation, on the W. coast of N. Africa. This information was probably obtained from the first navigators of these seas, who observed the elevated mountain which forms at Cape Geer (30° 40′ N. lat.) the western extremity, and as it were the gableend, of that extensive range, now comprised under the name of Mount Atlas.

The principal and according to our present knowledge the highest range of Mount Atlas, is that which begins at Cape Geer (near 100 W. long.), and extends E., with a slight declination to the N., as far as 50 W. long., where it approaches 32° N. lat. As to cross it requires two days journey, its width may be estimated at from 30 to 40 m. Its height nowhere seems to exceed the snowline; for its highest summit, the Miltsin, 27 m. S. E. from the town of Marocco, has been measured by Lieut. Washington, and found to have an elevation of 11,400 feet above the sea. It is only once in about 20 years free from snow; during the winter months the N. declivity of this range is frequently covered with snow for several weeks; we do not know whether this be also the case with the S. declivity, but as it is turned towards the great African desert (the Sahara), and towards the hot winds blowing from that quarter, it is likely that snow falls rarely there, even on the highest summits. This range is called by the natives Djibbel Telge.

From the E. extremity of the Djibbel Telge a chain branches off on the S. side, which runs in a W.S.W.

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