418 MISCELLANEOUS STUDIES 



below the 40 meter level and the solution of the original differential 

 equation for surface temperatures after adding a term giving the rate 

 of temperature change due to upwelling. The monthly values deduced 

 in this way for the San Diego region agree very well with those 

 afforded by the observations. 



From the magnitude of the vertical velocity found from tempera- 

 tures and from certain results deduced from Ekman 's hydrodynamical 

 theory, the distribution of the horizontal and vertical velocity of the 

 water in a vertical plane perpendicular to the coast was deduced and 

 represented graphically. 



An independent estimate of the velocity of upwelling made from 

 the distribution of salinities in the upper 30 meter layer and of the 

 rate of evaporation at the surface agreed well with the other two 

 estimates. Moreover, the estimates of the velocity of upwelling from 

 the temperature or salinity distribution did not depend upon the 

 cause of the upwelling ; but it is an interesting fact that such a vertical 

 current would be expected along the California coast from Ekman 's 

 hydrodynamical theory. 



I wish to express my obligation to Dr. W. E. Ritter of this institu- 

 tion, and to my laboratory assistant, Mr. Nephi W. Cummings, for 

 his aid in making the computations and for his suggestions while 

 preparing the manuscript. 



Transmitted June 26, 1918. 

 Scripps Institution for Biological Research 

 of the University of California, 

 La Jolla, California. 



