36 AKSEL S. STEEN. [2nd arc. exp. fram 



THE OBSERVATIONS. 



The following tables contain, in chronological order, all the deflec- 

 tion and vibration observations made, and the value of the horizontal 

 intensity, H, calculated from each separate series. 



OBSERVATION OF DEFLECTION. 



The deflector, magnet V or VI, was first placed upon the western 

 half of the deflection rod with its north pole towards the west, and was 

 then moved over to the eastern half of the rod with the north pole as 

 before. The deflector was then turned round so that the north pole 

 pointed east, and was finally, in the same position, moved across to 

 the western half of the rod. With each of the four positions of the 

 deflector, a setting of the decUnation needle was made, with the accom- 

 panying reading of the horizontal circle, and temperature reading. 

 t = the temperature read. 

 M = reading of the horizontal circle (the mean of the two ver- 

 niers). 

 6 = correction for the angular inequahty^. 

 (p = angle of deflection corrected for angular inequahty. 

 % = correction to be added to log sin (p for reduction to 0° ac- 

 cording to formula (4), p. 29. 



' Nansen Expedition. T. M., p. 66. 



