72 



FRIDTJOF NANSEN. 



M.-N. Kl. 



Stat. 41. This may be the reason why the surface-drift at Stat. 20 had a 

 more southerly direction than at Stat. 41. 



The most striking difference is, however, that according to our dia- 

 grams, Fig. 64, the average real movements at 10 metres and 20 metres 

 do not seem to have differed very much from the drift of the ship, and 

 there cannot have been any reaction-current at 10 metres similar to that 

 found at Stat. 41. The explanation is obviously that at Stations 19 and 20 

 there was no such well-marked surface-layer with low salinity and low 



density as was observed at Stat. 41. 

 The salinity at the surface was in most 

 cases above 33 %o. and at 10 metres 

 it was even, as a rule, about 33.50 ^'qq 

 or more. The salinity and density 

 gradually increased downwards without 

 any sharp boundary between a light top 

 layer and the heavier underlying water. 

 Thus a special system of currents could 

 not be developed in the top layer. 

 Fig. 64. Progressive Vector Diagrams of By means of our progressive dia- 



the relative movements at 10, 20, 50, and grams of the relative movements, Fig. 

 520 (and 54O1 Metres, at Stat. 20. The r , ^ r ■,, ■ 



64, we nnd the lollowmg average velo- 



100 cm./S€c. 



curves give, for each hour, the direction 



(with velocity) towards which the water 



moved relatively to the ship, between 



Aug. 5 I p. m. and Aug. 6 i a. m. 



cities and directions of the real move- 

 ments between noon and midnight on 

 August 5th: 



At the Surface 7.8 cm. per second towards Ssi^W (S44"W magn.l 



10 metres 8.4 „ „ „ S 31 «^ W (S 44» W „ ) 



„ 20 „ 9.2 „ „ „ S 35OW (S48OW „ I 



50 „ 7.5 „ „ „ S 25O E (S 12OE „ I 



The average direction of the current at 50 metres would consequently 

 have been deflected about 56^ towards the left of the average surface drift 

 and the current at 10 metres, and 60*^ towards the left of the average 

 direction of the current at 20 metres. This is quite different from our 

 experiences at Stat. 41. It is an interesting fact that at the latter station 

 the great deflection of the current towards the right from 20 metres to 

 50 metres, coincides with a great decrease in its velocity; while at Stat. 

 20 there seems to have been no great difference between the velocities of 

 the currents at the surface, at 10, 20, and 50 metres. There is also no 

 deflection towards the right (except the doubtful 4" from 10 to 20 metres), 

 the deflection being in the opposite direction, towards the left, from 20 

 to 50 metres. 



