376 



MISCELLANEOUS STUDIES 



From table 6, which gives the observed temperature averages at 

 different depths and months, the constants of equation (116) or the 

 simpler approximate form equation (117) will now be determined. 

 The mean annual temperature 6 m is given by the first two terms 



}-D = e m (iis) 



(119) 



which can be put in the linear form 



e (e m Z>)= Log e + \y. 



Assuming different values of D, plotting the results, and selecting the 

 value of D, for which the points fell most nearly on a straight line, 

 resulted in the following values of the constants: 



= 5.6, = 8.3, X = .004 



or 



(120) 



where y is the depth in meters. 



The satisfactory agreement between the computed and observed 

 values of m , shown by table 7, proves that the form of the function 

 deduced from theory differs but little from the true form. 



TABLE 7 



Computed and observed mean annual temperatures at a series of depths from 



40 to 700 meters 



The time of minimum wind velocity is in December, that of the 

 maximum is in July (McEwen, 1912, p. 265), and the magnitude of 

 the wind velocity, and therefore the vertical velocity of the water, 



is approximately proportional to 1 -|- r cos - where t = 12 corre- 

 sponds to the time halfway between June and July and r = 0.2. 

 Also since, as shown by table 6, the temperatures have the same period 



as the wind, ai = a = ^ in equation (117). In order to determine 

 o 



the remaining constants substract from the observed temperature for 



