46 FRIDTJOF NANSEN. M.-N. Kl. 



per second towards S yo'^W (magn.), assuming that the water at 400 metres 

 had no movement. Thus the observations with the two methods agree 

 fairly well in this case. 



On the whole, it would naturally have been desirable to have had a 

 greater number of observations at smaller intervals at all depths, but this 

 was difficult to attain as I had to read all the instruments myself, and some 

 rest proved necessary during the many consecutive hours, day and night, 

 that the observations lasted. 



In addition to the current-measurements I also repeatedly took the 

 temperature and water-saples at different depths during the same time, in 

 order to follow the vertical oscillations of the strata, and compare them 

 with the changes in the current. There was altogether so much work for 

 one man that it would have been difficult to do more. 



The current-observations were made with 3 Ekman current-meters. 

 No. 49, 52, and 53. No. 52 got out of working-order on August 4th, in 

 the evening, and No. 53 was used instead after that time. The formulae 

 for computing the velocity, directly observed with the different instruments, 

 were the following: 



For current-meter No. 49, if the velocity be between 3.5 and loi 



cm. /sec. : 



V = 0.9 -\- 26.0 X n 



The current-meter No. 52, if the velocity be between 3.3 and too. 5 

 cm. /sec. : 



V =^ 0.7 -|- 26.7 X n 



For current-meter No. 53, if the velocity be between 3.3 and 30.7 

 cm. /sec. (or less than 1.3 revolutions of the propeller per second): 



V ^= 1-3 4" 26.6 X n 



If the velocity be between 30.7 and loi cm. /sec. the formula is: 

 !-• = o.i + 27.5 X n 



n is the number of revolutions of the propeller of the instrument per 

 second. 



The original observations and the velocities thus computed are given 

 in the six first columns of Table II. The latter values with the true direc- 

 tion of these observed movements are collected in special tables for each 

 depth, pp. 47 and 48. 



These observations give directly the differences between the move- 

 ments of the ship and at the depth where the observations were taken. 



