1545 



ATLANTIC OCEAN. 



ATLANTIC OCEAN. 



616 



its waters to the Caspian Sea. No European river of the first or 

 second class flows immediately into the Atlantic Ocean ; the largest 

 being probably the Rhine, whose course does not exceed 700 English 

 miles. But three rivers of the second class, the Nile, the Danube, and 

 the Dnieper, enter the Mediterranean Sea or its branches. The 

 boundary line which marks the region from which the waters run 

 into the Atlantic Ocean on the east is extremely irregular. On the 

 north it begins with the most northern extremity of the TJralian 

 Mountains, and follows that range to near the 61st parallel, where, at 

 the sources of the Kama, it suddenly turns to the south-west and then 

 to the west, in which direction it continues to the sources of the 

 Volga, hardly 160 miles distant from the Gulf of Finland. From this 

 point it runs nearly south to 55 N. lat., from which it extends 

 east-south-east between the tributaries of the Volga on one side, and 

 of the Dnieper and Don on the other. Having thus attained 

 to 45' of E. long., and nearly 62 of N. lat., it takes a due 

 southern direction between the rivers Don and Volga, and nearly 

 traversing the middle of the Caucasus, it declines to the south-west, 

 and K-paratea the upper course of the Euphrates from the small 

 rivers which fall into the Black Sea and the Gulf of Scanderoon. It 

 then runs along the coast of Syria at an average distance of less than 

 100 miles, and turns round to the Isthmus of Suez. In Africa it 

 incloses the valley of the Nile, the upper part of which is of unknown 

 extent. To the east of this river the boundary of the Atlantic runs 

 along the shores of the Red Sea, a branch of the Indian Ocean, and 

 at the sources of the Nile it is at least 1600 miles distant from the 

 Mediterranean Sea, and consequently from the Atlantic, the greatest 

 distance which it probably attains in the Old World. From near the 

 mouths of the Nile it runs due west, following generally the 80th 

 parallel till it arrives at the shores of the Atlantic, opposite the 

 Canary Islands. To the south of the 30th parallel the boundary of 

 the drainage of the Atlantic Ocean falls in with its shores ; the great 

 African desert not being included in it. What parts of Africa south 

 of the Sahara belong to the basin of the Atlantic Ocean our present 

 geographical knowledge does not enable us to decide with accuracy. 

 Perhaps we shall not much overrate it in supposing that the drainage 

 of half of its surface flows to the Atlantic. We therefore may sup- 

 pose that the basin of the Atlantic contains about three millions of 

 square miles in Europe, not half a million in Asia, and about six 

 millions in Africa; which all taken together do not amount to more 

 than nine millions and a half, or about one-fourth of the continent of 

 the ancient world ; but the new continent belongs almost entirely to 

 its basin. 



In South America, the watershed between the Pacific and Atlantic 

 i rung at a distance of from 25 to 200 miles from the shores of 

 the former, except in the very southern extremity of the Ande 

 f AXDBS] ; and the extensive plains which cover the greatest part of 

 the surface of that continent send their waters to the Atlantic Ocean. 

 Probably not less than six millions of square miles of the surface of 

 South America belong to the basin of the Atlantic, and only half a 

 million to that of the Pacific Ocean. In North America, the line 

 which separates the waters falling into both oceans lies at a much 

 r distance from the shores of the Pacific Ocean ; but even here 

 the great plains to the east of the Stony Mountains send their rivers 

 to the Atlantic : so that if we assign to the Pacific Ocean even the 

 northern region traversed by the Mackenzie River, the area drained 

 by the rivers falling into the Atlantic may amount to upwards of six 

 millions of square miles, whilst those falling into the Pacific probably 

 flu nut dniin more than two millions. According to this account the 

 basin of the Atlantic Ocean comprehends above twenty-one millions of 

 square miles on both continents ; and the remainder, amounting to 

 about twenty-seven or twenty-eight millions, belongs to the basins of 

 the Pacific and Indian seas, and to those of a few inland lakes, or to 

 a few deserts which have no water. 



The Atlantic Ocean being in the present state of the commercial 

 world the most frequented high-road of communication, has been 

 examined more completely than the other seas with respect to its 

 facilities for navigation. The dangers and difficulties produced by 

 numerous and intricate groups of islands are of less frequent occur- 

 rence in this sea than in any other, for if we except the chain of 

 islands which separates the Gulf of Mexico and the Caribbean Sea 

 from the Atlantic, and which therefore are to be considered as 

 forming part of the shores of the ocean, it can hardly be said to 

 contain any group of islands between 50 N. lat. and 50 S. lat. 

 The groups of the Azores, Canaries, and Cape de Verde Islands, as 

 well ag those of Guinea and the Bermudas are small, and present 

 few difficulties to navigators. The Canaries including Madeira are 

 much resorted to by vessels, from their situation on the verge of the 

 regions in which the elements essential to navigation (namely, the air 

 and the water) undergo a change : for to the south of that group 

 the winds as well an the mutiini <>f the sea or the currents are 

 generally much less changeable than in the latitudes nearer to 

 the poles. 



winds and currents of the Atlantic require a more specific 



<pecting them then Inn) 1 |,,it comparatively few and 



iitions made to our knowledge from the publication 

 of the elaborate investigations and generalisations of Major Rennell 

 in 1833, until the last year or two, .when the results of a new and 



most important series of observations made under the direction of 

 the government of the United States were made known. These 

 results are very important, and the nature and extent of the obser- 

 vations and investigations now hi progress justify us in anticipating 

 still further and more important results. The system of observations 

 originated with Lieut. M. F. Maury, Superintendent of the Obser- 

 vatory at Washington, who in 1842 submitted to the Chief of .the 

 Bureau of Ordnance and Hydrography a scheme which was at once 

 adopted, for the making regular and systematic daily observations by 

 the captains and masters of vessels of the naval and merchant service 

 of the United States. They are directed to enter in their logs the 

 direction of the wind at least once in every eight hours ; the direction, 

 velocity, depths, and limits of the various currents, the temperature 

 of the air, and at the same time that of the water at the surface, and 

 when practicable at various depths of the sea ; and also to note 

 down all remarkable phenomena which may appear to have any 

 bearing on the main objects of inquiry. The masters of whaler* 

 have also special instructions given them to note down the regions 

 where whales are found, and particularly the limits within which 

 the ' right whales ' are met with. Each of the captains at the end 

 of his voyage transmits to the proper office what is termed his 

 ' Abstract Log,' which is the record of the series of observations he 

 has made. These logs are then by a staff of officers appointed 

 for the purpose examined, discussed, and the results tabulated, and 

 finally embodied in charts of the winds and currents, and in ' sailing 

 directions ' to every part of the globe. Of these abstract logs enough 

 had been collected at the date of Lieutenant Maury's Report (1851) 

 " to make 200 large manuscript volumes, averaging each from 2000 to 

 3000 days' observations ; " and the number has since been constantly 

 and rapidly increasing : the logs of a large number of whalers and 

 other vessels navigating the Atlantic for several years previous were 

 also examined and tabulated. At first the scheme met with a cold 

 reception from masters of vessels generally, but the great practical 

 value of the results soon caused them to enter upon their part in it 

 with much zeal and earnestness, and now there are said to be above 

 1000 of them engaged in making these observations. In return for 

 their labours they receive freely copies of the wind and current 

 charts and of the sailing directions corrected up to the latest dates ; 

 and the value of these will be perceived when we add that by these 

 directions the routes to all the most frequented ports have been 

 considerably shortened, in the instance of that from New York to 

 San Francisco for example nearly one-third, and in that to Rio 

 Janeiro about 700 miles. The course and limits of currents and 

 trade-winds have been determined with singular accuracy, and the 

 most serviceable information registered respecting the bounds of the 

 haunts of the 'right whales.' The great success of this system of 

 co-operation and the importance of extending it as widely as possible, 

 led the United States government to request the co-operation of the 

 British government in carrying out a similar system of observations 

 and their mutual interchange. The President and Council of the 

 Royal Society of London, to which our government applied for its 

 opinion on the desirableness of such a uniform system of observations, 

 in a Report dated July 1852, strongly urged its importance upon the 

 Board of Admiralty. " We possess," they observe, " in our ships of 

 war, in our packet service, and in our vast commercial navy, better 

 means of making such observations, and a greater interest in the 

 results to which they lead, than any other nation ; for this purpose, 

 every thip which is under the control of the Admiralty should be 

 furnished with instruments properly constructed and compared, and 

 with proper instructions for using them : similar instructions for 

 making and recording observations, as far as their means will allow, 

 should be given to every ship that sails, with a request that they 

 will transmit the resiilts of them to the Hydrographer's Office of the 

 Admiralty, where an adequate staff of officers should bo provided 

 for their prompt examination, and the publication of the improved 

 charts and sailing directions to which they would lead. Above all 

 it seems desirable to establish a prompt communication with the 

 Hydrographer's Office of the United States, so that the united labours 

 of the two greatest naval and commercial nations of the world may 

 be combined, with the least practicable delay in promoting the 

 interests of navigation." Such a union would indeed be most 

 desirable. As yet, we learn by a statement recently made by Earl 

 Granville in the .House of Lords, that no positive steps have been 

 taken by the English government, but that the subject is under the 

 consideration of the Treasury we may fairly hope with a view to 

 the most efficient means of carrying out the plan. 



We now proceed to our more immediate object, the nature of the 

 winds and currents of the Atlantic. 



With respect to the winds, the whole surface of the Atlantis 

 Ocean may be divided into three regions, in one of which the winds 

 maintain a constant course from east to west, and have obtained thv 

 name of trade-winds. This region extends to about 80 of lat. on 

 both sides of the equator. The two other regions to the north and 

 south of the 80th parallel in both hemispheres are subject to n 

 continual change of the winds, and are therefore called the rri'ion 

 of variable winds. To these ought perhaps to be added the region 

 of equatorial monsoons recently ascertained. 



It is not here our object to enter into an explanation of the 



