X. 



TEMPERATURES OF THE CARIBBEAN, GULF OF MEXICO, AND 

 WESTERN ATLANTIC. 



Having given the reader a general sketch of the configu- 

 ration of the sea - bottom in the districts traversed by the 

 "Blake," we may now pass to an examination of the tempera- 

 tures and currents of the sheet of water covering: that regfion. 

 (Fig. 140.) The temperature sections of the Gulf of Mexico 

 were obtained mainly by Lieutenant-Commander Sigsbee ; those 

 of the Caribbean and along the Gulf Stream, with the exception 

 of the few observations made by the " Albatross," were taken 

 by Commander J. R. Bartlett on the " Blake." They are here 

 reproduced as they have been kindly sent to me by Professor 

 J. E. Hilgard, Superintendent of the Coast Survey.^ 



Of course, during the cruises, sound- 

 ings were taken with Sigsbee's modifica- 



1 In addition to the graphic method of representing 

 each temperature section which has been adopted on 

 many of the maps of this vohime, it has been found 

 convenient to construct curves (Fig. 141), showing at a 

 glance the temperature at any depth. By su- 

 perposition the curves of separate observations 

 may be readily compared ; in the same way, 

 we may, by means of curves, bring 

 to the eye at once the thermal 

 conditions of such distant points 

 as we wish to contrast. In at- 

 tempting thus to set forth the 

 temperature of currents, we 

 should not forget that at every 

 moment they are changing in di- 

 rection and intensity, much as are 

 the atmospheric currents ; and 

 their graphical representation merely gives us their most general features, leaving 

 the local disturbances to be more or less accurately defined. 



Fig. 141. — Temperature Sections. (Curves.) 



