176 V. WALFRID EKMAN. 



were any constant currents found, and it was impossible to decide 

 whether the variations were due to untrustworthiness in the 

 apparatus, or whether the irregularity in the currents really 

 existed. In order that the instrument might certainly come to 

 rest, it was allowed to hang quietly for % 3, or even 5 mi- 

 nutes before being arrested. 



When, however, observations were made nearer the surface, 

 the true facts were revealed. It then appeared that near the ice 

 perfectly regular currents were to be found, extending to various 

 depths, generally to about two metres below the ice. Within 

 these depths, the apparatus did not need more than half a 

 minute to come to rest, and give concordant results. It was 

 thus evident that the irregularities at greater depths lay in the 

 currents themselves. To allow the apparatus a longer time in 

 which to come to rest, was rather harmful than otherwise, as 

 the time between the observations was then also lengthened. 



P'igs. 5 — 7, PL XVIII, show the currents observed on the 

 9th April at Station I, nearest the mouth of the river. At a depth 

 of 0'5 metres below the ice, there is a perfectly regular current, 

 flowing in a southerly direction, with a mean velocity of 3'2 cm. 

 per sec. This is probably produced by the river-water flowing out 

 here. Even at a depth of 1*4 m. the current is quite inconstant 

 to its direction; but nevertheless the southern main direction can 

 be distinctly recognised beside a tendency towards the west. 

 The mean current is about SW. by S., 1 cm. per sec. At a 

 depth of 13 m. (near the bottom), the current is altogether irre- 

 gular. The mean resultant of all the observations in this depth, 

 gives only 0"9 cm. per sec. towards the NNE., while the mean 

 of the velocities is 3'3 cm. per sec, and the former, 0"9 cm. 

 per sec, is altogether too small to be regarded as other than 

 accidental. 



The same transition to irregular movement in deeper water 

 is also shown by the observations at Stat. II, on the 10th April 

 (PI. XVIII, figs. 8—13). Here, however, the regular currents extend 



