322 



ATLANTIC OCKAN ATLANTIDES. 



plied when tin- ships U-nr against each other, or 

 when they nre at a small disumce ; the tran^erM- 

 position of the former to tin- latter Iwinjj principally 

 underwood. Athwart the fore-foot denotes the flight 

 of a cannon-ball from one ship across the course of 

 another, to intercept the latter, ami oblige her to 

 shorten sail, that the former may come neur enough 

 to examine her. 



ATLANTIC OCEAN ; the mass of water between the 

 western coast of Europe and Africa, and the eastern 

 coast of America; the only considerable aquatic 

 communication between the polar extremities of the 

 earth, if we do not give to both its extremities the 

 name of the Frozen ocean. The name is derived 

 from Atlas, (q. v.) The Atlantic, in its narrowest 

 lart, between Europe and Greenland, is upwards of 

 1000 miles wide, and opening thence to the S.W. 

 with the general range of the bounding continents, 

 spreads, under the northern tropic, to a breadth of 60 

 decrees of longitude, or 4170 miles, without estimat- 

 ing the gulf of Mexico. Beyond the torrid zone, the 

 A. inflects to the N. W. and S. E., again complying 

 with the bearing of the adjacent continents, which 

 correspond with great exactness to each other. The 

 A. and its gulfs occupy about the seventh part of the 

 superficies of the globe, curving round the western, 

 southern, and northern part of the eastern continent, 

 from 72 N. lat, to 35' S. lat., or through 107 degrees 

 of latitude. This immense strait is limited, on the 

 west, by the most lengthened land-line, extending 

 north and south, that can be drawn on the earth. 

 " When we cast an eye over the Atlantic," says 

 Humboldt, in his Personal Narrative, " or that deep 

 valley which divides the western coasts of Europe 

 and Africa, from the eastern coast of the new conti- 

 nent, we distinguish a contrary direction in the mo- 

 tion 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 hun- 

 dredths 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 hemis- 

 pheres, with those which are laid down in the Voy- 

 ages of Cook, la Perouse, d'Entrecasteaux, Vancou- 

 ver, Macartney, Krusenstern, and Marchand, I found 

 that the swiftness of the general current of the tro- 

 pics varies from 5 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 asfar 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 

 3() and 48 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 northward, 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 Carib- 

 bean sea, and thence, between Cuba and Yucatan, 

 into the Gulf of Mexico. In the latter reservoir, it 

 lias 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 United 



States ami Nova Scotia, to about 50 N. lat., mctta 

 the Arctic currents from Davis's straits, and from 

 li.e Northern Atlantic ocean, is turned towards Fu- 

 rope 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 gvlf- 

 stri'ttm. It is the second most extensive, and iniu-li 

 the most strongly marked whirlpool on the globe, 

 having an outline of about 15,000 miles. The mean 

 motion of the gulf-stream is, no doubt, changeable, 

 even at the same points. The time of its periodical 

 revolution is about 2J 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 2Gth und 

 27th degrees of latitude, a celerity of 80 miles in 24 

 hours, or 5 feet 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 some- 

 times 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 endeavoured 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 six or seven metres higher than that of the lat- 

 ter (nineteen or twenty-two 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. e. 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 neighbourhood of the 

 British isles, the salt has been stated at one-thirty- 

 eighth of the weight of the water ; and, according 

 to Dr Thomson, the proportion of saline contents 

 does not appear to differ much, whatever may be the 

 latitude in which the water is examined. The varia- 

 tion resulting from all the observations of Pages, 

 Phipps, and Baume, is from 0451 to 0-35 saline 

 matter. The temperature of the A. is highest be- 

 tween 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 be- 

 tween North America and Europe. We do not 

 know that there exists an exact comparison of the 

 natural history of the A. with that of other oceans. 



ATLANTICA, Atland eller Manheim ; a work, in La- 

 tin and Swedish, by O. Rudbeck, in which the 

 author, with great learning, labours to prove a ludi- 

 crous hypothesis, that the Atlantis of the ancients 

 was Sweden, and that the Romans, Greeks, English, 

 Danes, and Germans, originated from Sweden. The 

 work is a typographic rarity. The first volume ap- 

 peared in 1675-79, at Upsal ; several editions of it 

 followed. The last Latin edition is of 1699, and 

 bears a high price. Written copies of it are in seve- 

 ral European libraries. 



ATLANTIDES ; pillars, in the form of a man, used 

 in building, to support a projection or a cornice. See 

 Caryatides, 



