Vol. 4] 



Hohvay.—Cold Water Belt. 



269 



Southward of San Francisco the temperatures in the table 

 do not show such marked variations. The first three lines — all 

 north of Point Conception — are in harmony with the existence 

 of an inshore belt of cold water. South of Point Conception 

 there is no evidence of such a cold belt. As indicated in the 

 table the length of the lines south of San Francisco is less than 

 that of those to the north. The Point Sal and the San Nicolas 

 lines also vary greatly from east and west lines. 



South of Point Conception, the submarine plateau or con- 

 tinental shelf is much wider ; that is, there is a much broader 

 area of comparatively shallow water. This wider continental 

 plateau and the bend in the coast line at Point Conception are 

 probable elements in the causes which determine the absence of 

 a marked inshore belt of cold water off southern California. 



The temperatures in the table with those obtained by the 

 Tuscarora in the cable survey from San Diego to Honolulu have 

 been laid off on the coast survey charts; the cable survey tem- 

 peratures, like the others already considered, give no indication 

 of a cold belt near shore, south of Point Conception. For the 

 first 150 miles from San Diego, the surface temperatures vary 

 from 58° to 59°. Beyond that, the temperature slowly rises as 

 the line runs to the west-southwestward to the Hawaiian Islands 



TEMPERATURE OBSERVATIONS OP THE ALBATROSS. 



In 1891-2 two surveys were made by the U. S. S. Albatross, 

 between Monterey Bay and Honolulu — the one on a great circle, 

 the other on a rhumb line. On the great circle line, the surface 

 temperatures for the first 150 miles vary from 54° to 56°. It 

 then rises to 59°, drops to 57°, and rises to 62°. After that it 

 rises slowly as the line runs toward the tropics. The observa- 

 tions on the Monterey end of the survey were made in October, 

 1891. On the rhumb line in January, 1892, the temperature 

 off Monterey Bay was 52°, rising to 59° in 140 miles. Even 

 with a liberal allowance for the southing made on these lines, 

 the surface temperatures near shore are distinctly lower than 

 further to the westward. 



