396 THYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. 



being assumed that the drift or flow is from the poles when the 

 temperature of the surface water is below, and from the equatorial 

 regions when it is above that due the latitude. Therefore, in a 

 mere diagram, as this plate is, the numerous eddies and local 

 currents which are found at sea are disregarded. Of all the 

 currents in the sea, the Gulf Stream is the best defined ; its limits, 

 especially those of the left bank, are alwaj's well marked, and as 

 a rule, those of the right bank, as high as the parallel of the 

 thirty-fifth degree of latitude, are quite distinct, being often 

 visible to the eye. The Gulf Stream shifts its channel (§ 124), 

 but nevertheless its banks are often very distinct. Ships, in 

 crossing! the edges of it, can sometimes know it by the colour of 

 the water ; at other times they find, as they pass along, the 

 temperature of the water to change 8° or 10° in the course of as 

 many minutes ; as an example of this, I quote from the abstract 

 log of the " Herculean," in which Captain William M. Chamber- 

 lain, being in latitude 33° 39' north, longitude 74° 56' west (about 

 one hundred and thirty miles east of Cape Fear), remarks : 

 " Moderate breezes, smooth sea, and fine weather. At ten o'clock 

 fifty minutes, entered into the southern (right) edge of the 

 Stream, and in eight minutes the water rose six degrees ; tho 

 edge of the stream was visible, as far as the eye could see, by 

 the great rippling and large quanties of Gulf weed — more * weed ' 

 than I ever saw before, and 1 have been many times along this 

 route in the last twenty years." In this diagi'am, therefore, I 

 have thought it useless to attempt a delineation of any of those 

 currents, as the Kennell Current of the North Atlantic, the 

 *' connecting current" of the South, "Mentor's Counter Drift," 

 " Eossel's Drift of the South Pacific," etc., which run now this 

 way, now that, and which are frequently not felt by navigators 

 at all. In overhauling the log-books for data for this chart, I 

 have followed vessels with the water thermometer to and fro 

 across the seas, and taken the registrations of it exclusively for 

 my guide, without regard to the reported set of the currents. 

 When, in any latitude, the temperature of the water has appeared 

 too high or too low for the latitude, the inference has been that 

 such water was warmed or cooled, as the case may be, in other 

 latitudes, and that it has been conveyed to the place where found 

 through the great channels of oceanic circulation. If too warm, 

 it is supposed that it had its temperature raised in warmer 

 latitudes, and therefore the channel in which it is found leads 



