THE GULF STBEAM. 385 



breadth of 150 miles. This portion of its course, from the channel within 

 the Matanilla, is about 590 miles in length. 



To the Northward of this, its N.W. edge still follows the edge of the 

 bank of soundings, and being diverted more to the East by the obstacles 

 lying off it, gradually winds more to the Eastward towards the parallel of 

 40°, to a line transverse to its course trending S.E. from Cape Cod, which 

 will be about 480 miles beyond the Cape Hatteras section. It is here 

 from 250 to 300 miles broad. Beyond this it pursues an Easterly course 

 for 1,150 miles to the meridian of 40° W., which is 350 miles East of the 

 Great Newfoundland Bank. After skirting the Southern edge of the Banks 

 of Newfoundland, it proceeds with diminished velocity and temperature 

 to about the meridian of 40° W. just named, when its farther drift to 

 the Eastward cannot be distinguished from that of the whole surface 

 of the Ocean to the North and South of it. The total distance we have 

 thus gone over will be about 2,600 miles, throughout the whole of which 

 ipts characteristics may be distinctly traced, although its lateral boundaries 

 are not so easily defined. 



It has been usual to extend its independent existence some 1,200 or 1,500 

 miles farther to the shores of Western Europe, as before stated, but when 

 its volume in the outset, or in its narrowest part, is considered, it will be 

 no great sacrifice of previously formed opinions to curtail it of its more 

 extended features. Although thus deprived of a large portion of the 

 magnitude with which it was formerly believed to be invested, it is not the 

 less a wonderful stream, as it is able, so expanded and thinned out, to 

 maintain its course and character unimpaired over the counter-currents oi 

 a totally different origin and nature wnich flow beneath it. 



(371.) Throughout the latter part of its course its left-hand margin 

 carries the greatest strength. In the Gulf of Florida its Southern side is 

 the most powerful. Northward of the Gulf its Eastern and South-Eastern 

 side is difficult to define, as it is found that the Gulf Stream may be said 

 to consist of several longitudinal bands of water of different temperatures 

 as presently described. To the Southward of British North America its 

 force gradually disappears till it is lost in the central still water of the 

 Sargasso Sea. 



The diagram of the Currents, which elucidates this section, will give a 

 clearer idea of its relation to the great circulatory system, than any long 

 description can do. 



(372.) Breadth. — As stated above, it is difficult to define the exact 

 boundaries of the Gulf Stream, especially its Southern side, where, owing 

 to the accession of the warm drift outside the islands (366), temperature 

 observations form no guide. Whilst the more minute examinations which 

 have been made have added much to our knowledge of its features, they 

 have not hitherto been sufficiently extensive to fix its limits, either by an 

 average, or to give us the position of its margin in different seasons. How- 

 ever, as numerous observations have been given on its drifts, we may give 

 a rude approximation to its extent from the positions where the drift has 

 been found to be appreciable. In the narrowest part it is about 40 miles 

 broad — a breadth it maintains to abreast Cape Canaveral. Off Charleston 

 ^V. A. 0. 50 



