-11- 



In the last line of the tables the data for the 

 different zones of each cruise are added together. This corresponds 

 to an additional averaging in space along a line at right angles 

 to the current over a distance of about 80 km. A mean eddy 



heat flux with a range from 1 to 4 C cm sec" and a mean eddy 



? -1 -2 



density flux of -0. 2 to -1. 8 x 10" gm sec cm is found. 



The reliability of the measured covariances 

 is estimated by use of the standard error of the mean, computed 

 as the standard deviation divided by the square root of the 

 number of observations, e. g. , S. £.(^77^)= ^i^"^')^-i.^^^) //sF . 

 Twice the standard error of the mean gives the value of the 95% 

 confidence limit. It is assumed that the observations are in- 

 dependent, which is not exactly true since the observations 

 in each zone are taken in the most favorable case 12 hours 

 apart. There will be some correlation in time between the 

 different observations, which will tend to give too small 

 standard errors of the mean. In the average of all data for 

 a cruise, there will be a correlation of the observations in 

 space as well as in time. However, the close resemblance 

 of the results of three independent cruises, which were made 

 in different years and different parts of the Gulf Stream, 

 supports the suggestion of an existing positive transport of 

 heat and negative transport of density in the layers 



