ON A NEW CURRENT-METER. 



173 



pendulum. The influence of this asymmetry was determined 

 to be equivalent to a current-pressure of 0*35 or 0*45 gr. ; and 

 thus all the current-observations incur the chance of an error of 

 as much as 0"45 gr. 



It appears, therefore, that it is necessary to carefully adjust 

 the pendulum before an instrument is taken into use, as also 

 to control it from time to time; and special care should be ex- 

 pended upon its construction. In the experiments in question, 

 the error was adjusted by balancing the pendulum with a small 

 lead weight near its upper end. 



As the pressure of the current in these experiments was too 

 small, the results of the separate observations could not be put 

 down on the diagram, but only their means for each of the 4 

 velocities examined. 



They are: 



Velocity 

 Current-pressure 



0-464 

 0045 



0-695 

 0-11 



0-93 

 0-25 



1-39 

 0-64 



The result of the experiments is, that the pressure, P, varies 

 with the velocity, v, nearly according to the equation 



P = 0-243 t;!-^^ 



and thus the curve is drawn on the diagram. 



2. The Current-Observations and their Results. 



The author wishes to state at the outset that the current-ob- 

 servations made on the ice on Lysaker Fjoi'd, of which the pri- 

 mary object was to find out the practicability and adaptability 

 of the instrument, have not given any hydrographie results in 

 the form of a complete representation of the currents in the fjord. 

 Only scattered, small observations and indications concerning the 

 "biology" — so to speak — of the currents have been gained; but 



