Vol. 4] 



Hohoay.—Cold Water Belt. 



275 



Harm* accepts the theory that the rise of cold water along the 

 coast is caused by the "suction effect" of winds blowing off 

 shore. In his general discussion he incidentally remarks "that 

 the sharp deflection of an ocean current off shore may cause a 

 rise of cold water from below." He does not apply the latter 

 ideas to any of the areas which he discusses, which are substan- 

 tially those mapped by Andrees. The whole California coast is 

 mentioned among others as if it belonged in the area of constant 

 trade winds. 



Buchananf discusses this subject and gives some data for our 

 coast. During his voyage from Valparaiso to San Francisco 

 in 1885 he stopped at Mazatlan. He states that on getting under 

 way from that port the surface temperature was 75.8° and "the 

 cold water must have been close to the surface, for water taken 

 from the wash when the steamer was going astern had a temper- 

 ature of 72.8°." Thence across the Gulf of California the tem- 

 perature was 78° and the water a deep blue color. Approaching 

 Cape San Lucas the temperature of the water fell to 73.4° and 

 then to 64.4° close inshore. After passing* the Cape the temper- 

 ature rose to 66.8° as the shore was left. Thence northward to 

 San Francisco the water grew colder, falling to 50° degrees at 

 the entrance to the bay. The low temperature found in passing 

 Cape San Lucas is the most important part of this account. The 

 cold water he found on the further trip to San Francisco being 

 on a single line parallel to the coast furnishes little basis for dis- 

 cussion. Mr. Buchanan offers the following comment: "The 

 occurrence of these coast areas of abnormally cold water is ex- 

 plained when we recognize that they are the windward shores of 

 the oceans. The trade winds blow from them toward the equator 

 and in so doing mechanically remove water, which has to be 

 supplied from the readiest source. This source is the deep water 

 lying off the continental coast which is supplied by the gradual 

 drift of water from high latitudes. Hence, though the low tem- 

 perature of the coast water is referred to as due to the cold of 

 high latitudes, it is not supplied by a long surface current, but 

 * Harm, Julius. Handbook of Climatology, 1903. 



t Buchanan, J. Y. Similarities in the Physical Geography of the Great 

 Oceans. Pro. Eoy. Geog. Soc, 1886, p. 753. 



