1910] McEwen: Preliminary Hydrographic R< port. 203 



graphical conditions of temperature, density, and current at 

 each place and at each depth, and then to learn the changes or 

 fluctuations that these conditions undergo during the year or 

 during longer periods." (2) Seen from the standpoint of spe- 

 cific biological investigations, the hydrographic problem may be 

 stated thus : Assuming a large body of knowledge answering 

 the demands and desires indicated under (1) to have been 

 secured, the problem then becomes : What particular condi- 

 tions, agreements with, or deviations from, the average condi- 

 tions, already found, prevail at the particular time and place at 

 which any particular biological observations are made? 



Methodologically considered it will be noted that investiga- 

 tions designed to answer the needs indicated under (1) might 

 be strictly, i.e., exclusively, hydrographic, while those designed to 

 answer the needs indicated under (2) would be always primarily 

 biological, i.e., the hydrographic observations would always be 

 made concomitantly with and subordinate to, the biological 

 observations. 



Stanford Univi rsity, March, 1910. 



