202 University of California Publications. [Vol.6 



Location Temperature Density 



Whistling buoy, just outside of the entrance to the bay 17.6 1.02500 



La Playa, five miles from the buoy 1.02514 



Spreekel'a wharf, three miles from La Playa 19.4 1.02538 



Perry landing on Coronado side 20.0 1.02547 



East end of Glorietta Bight 23.0 1.02592 



West end of Glorietta Bight 24.3 1.02598 



National City, one-quarter mile from shore 26.5 1.02670 



The fluctuation of the above values due to the tides is illus- 

 trated by the following observations. At low tide on July 18, 

 at 8 a.m., the temperature and density were 20.8° and 1.02564 

 respectively, near Spreckel's wharf; four hours later at the same 

 place, during high tide, the values were 18.0° and 1.02513. 



On a line from Spreckel's wharf to the west end of Glorietta 

 Bight. Coronado, July 18. 1908. there were five observations of 

 temperature and density. The minimum temperature was 20.0° 

 in the channel, the maximum was 24.3°, the average being 21.22°. 

 The minimum density was 1.02513. the maximum was 1.02598, 

 the average being 1.02562. Along the same line on July 17. 

 1909, there were seven observations taken. The minimum tem- 

 perature was 20.8°, the maximum was 24.3°, the average being 

 22.1°. The minimum density was 1.02644, the average being 

 1.02581. 



On July 14, 1908, there were five observations taken at 

 National City, about a fourth of a mile from the coast. The 

 minimum temperature was 24.8°, the maximum w.as 27.5°, the 

 average being 26.37°. The minimum density was 1.02670, the 

 maximum was 1.02704, the average being 1.02690. For the sum- 

 mer of 1908 the average temperature and density of San Diego 

 Hay were 23.79° and 1.02620. 



It may be profitable to state briefly, in concluding this pre- 

 liminary report, what the general hydrographic problems before 

 the Station are : ( 1 ) In its exclusively hydrographic aspect the 

 problem cannot be better worded than w T e find it in the Second 

 Report of the North Sea Investigations, 1904 to 1905 : "We want 

 to know the physical conditions under which marine life exists. 

 and we should like to know the conditions at all parts and all 

 depths of the sea at all seasons of the year, and from one year 

 to another. We want to learn the general, or average, hydro- 



