44 THE PHYSICiVL GEOGRAPHY OF THE SEA. 



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 surface can not be heated alike ; radiation here, 

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

 the unequal depths ; the breaking up of the fountains below, and 

 the bringing their cooler waters to the surface by the violence 

 of the waves, may all be expected, and are well calculated to pro- 

 duce unequal heating in the torrid and unequal cooling in the 

 temperate zone ; the natural result of which would be streaks and 

 patches of water differing in temperature. Hence it would be 

 surprising if, in crossing this drift and stream (Plate VI.) 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 has 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 differently -tempered streaks and 

 layers (§ 127) which are so familiar to navigators, and which have 

 been mistaken for "forks of the Gulf Stream." 



180. Curves showing some of these variations of temperature 

 Fig. A, Plate VI. havc bccu projcctcd by the Coast Survey on a 

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

 how these waters have arranged themselves off the Capes of Vir- 

 ginia into a series of thermal elevations and depressions. 



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

 The high tempera- drift of the watcrs to the east of it are worthy of 



tare and drift in the . ^ . _,, -_ . /a nrw i ti 



western half of North cousideratiou. Thc Japan current (§ oO) has a like 



Atlantic and Pacific n . ^ p i , o • , i /-r»i , ttt 



Oceans. driit 01 Warm water to the east oi it also (Plates V J . 



and IX.). In the western half, reaching up from the equator to 

 the Gulf Stream, both of the North Atlantic and North Pacific, 

 the water is warmer, parallel for parallel, than it is in the eastern 

 half On the west side, where the water is warm, the flow is to 

 the north ; on the east side, where the temperature is lower, the 

 flow is to the south — making good the remark (§ 80) that, when 

 the waters of the sea meet in currents, the tendency of the warm 

 is to seek cooler latitudes, and of the cool, warmer. 



132. The Gulf Stream of each has its genesis on the west side, 

 A Gulf Stream in ^^^ ^^ ^^^ coursc skirts the coast along ; leaving the 

 ^^^ coast, it strikes off to the eastward in each case. 



