THE GULT STREAIVT. 45 



129. The waters of the Gulf Stream form by no means the 

 Waters of the ocean onlj bodj of Warm Water that the thermo-dy- 

 Semi'o-d°nlmicJi ii^mical forces of the ocean keep in motion. Kearly 

 means. all that portion of the Atlantic which lies between 

 the Gulf Stream and the island of Bermuda has its surface covered 

 vdth. water which a tropical sun and tropical winds have played 

 upon — with water, the specific gravity of which has been altered 

 by their action, and which is now drifting to more northern climes 

 in the endless search after lost equilibrium. This water, more- 

 over, as well as that of the Gulf Stream, cools unequally. It 

 would be sm'prising if it did not : for by being spread out over 

 such a large area, and then drifting for so great a distance, and 

 through such a diversity of climates, it is not probable that all 

 parts of it should have been exposed to like vicissitudes by the 

 way, or even to the same thermal conditions ; therefore all of the 

 water over such a smiace cannot be heated ahke ; radiation here, 

 sunshine there ; clouds and rain one day, and storms the next ; 

 the miequal depths ; the breaking up of the foimtains below, and 

 the bringing then' cooler or their warmer waters to the surface 

 by the violence of the waves, may all be expected, and are well 

 calculated, to produce unequal heating in the torrid and unequal 

 cooling in the temperate zone ; the natm-al result of which would be 

 streaks and patches of water differing in temperature. Hence it 

 would be sm-prising if, in crossing this drift and stream (Plate YI.) 

 with the water-thermometer, the observer should find the water all 

 of one temperature. By the time it has reached the parallel of 

 Bermuda or " the Capes " of the Chesapeake, some of this water 

 may have been ten days, some ten weeks, and some perhaps 

 longer on its way from the "caldron" at the south. It has 

 consequently had ample time to arrange itself into those diflerently- 

 tempered streaks and layers (§ 127) which are so familiar to 

 navigators, and which have been mistaken for "forks of the Gulf 

 Stream." 



130. Curves showing some of these variations of temperatm-e 

 Fig. A, Plate VI. havo been projected by the Coast Survey on a 



chart of engraved squares (Fig. A, JPlate YI.). These curves 

 show how these waters have sometimes arranged themselves ofi' 

 the Capes of Yirginia into a series of thermal elevations and 

 depressions. 



131. In studpng the Gulf Stream, the high temperature and 

 drift of the waters to the east of it are worthy of consideration. 



