ON A NEW CURRENT-METER. 177 



to a greater depth than at Stat. I. They are still quite distinct 

 at a depth of 3 metres, but less so at 5 metres. On the other hand, 

 the currents are of undiminished force down to the very bottom. 

 At 29 m. (1 m. from the bottom), there are irregular currents 

 of the same velocity as the current at the surface. 



In tlie surface-current we can trace a slower, but as con- 

 siderable a change going on all the time (3V2 hours), and most 

 marked at a depth of 1*4 metres. It will be seen that the results 

 agree well within each group of observations separated from one 

 another on the dial, but that from 10 a. m. to 2 p. m., a complete 

 change in the current takes place at a depth of 1 or 2 metres. 

 In one group of each of the two depths, 1*4 and 2*2 m., the 

 changes follow regularly, as will be seen from the annexed tables, 

 in the order indicated by the fine lines connecting the various 

 points on the dials. This gives rise to the supposition that even 

 the small variations in the other groups are partly due to changes 

 in the current itself, only so rapid that the continuity cannot be 

 proved, as each observation takes at least from 1 to 5 minutes, 

 according to the depth. 



In the following table, the first column gives the hour at 

 which the messenger was released, and the second column, m, 

 the number of minutes during which the apparatus was previ- 

 ously left undisturbed in order to come to rest. The sixth col- 

 umn contains the coefficient, k, by which the displacement of 

 the pendulum must be multiplied in order to obtain the pressure 

 of the current. The meaning of the other columns is clear. 



Nyt Mag. i. Naturv. XXXIX, II. 12 



