198 University of California Publications. [Vol. 6 



density measurements taken. The minimum temperature was 

 9.9 and the maximum density was 1.02525. 



Usually the temperature is found to decrease continually 

 with increase of depth and the rate of change decreases rapidly 

 as the depth increases, and the density increases as the depth 

 increases. The following table of temperatures and densities 

 which applies to a station ten miles west of La Jolla is a good 

 illustration of the above rule : 



There were, however, several striking variations from the 

 normal relation of temperature and density to depth. V«v ex- 

 ample, a rise of 1.1°, from 9.4° at two hundred and fifty fathoms 

 to 10.5° at three hundred and eighty-five fathoms, was observed 

 on June 15. 1908. The densities were 1.02543 and 1.02511 re- 

 spectively. A rise of 3°. from 7.5° at five hundred and sixty 

 fathoms to 10.5 7 ' at five hundred and eighty-five fathoms, was 

 noted on June IS, 1908, twenty-five miles west of La Jolla. 

 Similar phenomena were observed during the summer of 1905 

 bet wren La Jolla and San Clemente Island. In nearly every 

 ease where the temperature rose with increase of depth, the 

 density diminished. 



The error in the above temperatures due to heating of the 

 bucket was eliminated by taking the temperature of the coldest 

 portion of the water, so the temperature variations found above 

 could nut be due to the method of measurement. 



THE OCCTJRKENCE AND PROBABLE SIGNIFICANCE OP COLDER 

 IN-SHORE SURFACE WATER.-' 



As will be seen from the map. page 191, from latitude 28° 36', 

 longitude 115° 9', northward to the coast and thence along a line 

 from two to ten miles from the coast, swinging off towards 



-All temperatures referred to under this title were observe 1 during the 

 summers of 1908 and 1909. 



