452 PHYSICAL GEOGEAPHY OF THE SEA, AND ITS METEOPtOLOGY. 



our co-operators "wiio will enter upon the investigation patiently and 

 ■^'ith diligence.* 



882. The observations that we possess do not prove that the 

 The warmest waters warmcst watcr of intertropical seas is not at the 

 i'Jc'Sev?Tto''rbSow^"-'^^^ce: thoj go no farther than to show that it 

 the surface ? is somctimes not at the surface, and to suggest that, 

 in all probabihty, it is generally below, especially in "blue water." 

 Eeason suggests it also. Supposing that, as a rule, the hottest 

 water is below the surface, we may, in order to stimulate research, 

 encom-age investigation, and insure true progress, propound a theory 

 in explanation of the phenomenon, looking to futm-e observations to 

 show how far it may hold good : — 



883. The flow of heat from the sun is held to be uniform, and 

 The annual supply of tlic quantity that is annually impressed upon the earth 

 solar heat uniform, jg considered as a constant. The sun spots may make 

 this " constant " a variable, but the amount annually received by 

 the earth is so nearly uniform, that our best instruments have not 

 been able to show us any variation in its uniformity. Some maintain 



* On the 26th of March, 1852, the late Passed Midshipman A. C. Jackson, 

 U. S. N., bein.o: in the Gulf Stream, lat. 84° 55' N., long. 74° 8' W., found the 

 temjjerature of tlie water 74'5^ at the surface, 79^ at the depth of six feet, and 

 86-5^ at the depth of 16| feet. Again, on the oOth, in lat. 24^ ]0' N , long. 80= 11' 

 W. (near the edge of the Gulf Stream), he tried the temperature of the water by 

 another carefully conducted set of observations, and found it 78^ at the surface, 

 and 795^ at the depth of 16J feet. The sea was rough, and he did not, for that 

 reason, observe the temperature at six feet. The temj^erature of the air in the 

 shade was 69-53 on the 26th, and 79-^ on the 30th. {Vide p. 59, 5th ed., Maury's 

 Sailing Directions, 1853.) 



Extract of a Letter from J. Bermingham, Chief Engineer of the American Steamer 

 "Golden Age," dated Bay of Panama, June 29, 1860, and addressed to Lieut. 

 John M. Brooke, U. S. N. 



*'0n- our late trip from San Francisco (June 5tli) to this port we experienced the 

 most remarkably fine weather and smooth sea that I have ever witnessed on the 

 Pacific, or anywhere else, 



" On the 14tl), wliile crossing the Gulf of Tehuantepec, we found the tempera- 

 ture of the sea water on the surface (where it had not been disturbed by the 

 progress of the vessel) 88^, and upon taking the temperature at the same time 

 ten feet below tlie surface the mean of three thermometers gave 90^^. Tempera- 

 ture of atmosphere 93^. 



•'I do not exactly understand why the temperature of the sea water should be so 

 much greater at a distance of ten feet from the surface than it was immediately 

 upon the surface, 



••Mr. Agassiz (a son of Professor Agassiz) was on board, and he and myself 

 made repeated tests of the temperature of tlie water during the four hours we 

 were running through it — the warm belt, 



♦• Ninety degrees is the highest temperature that I have ever known the water of 

 the ocean to attain." 



