i8 



SCIENTIFIC RESULTS OF ZIEGLER POLAR EXPEDITION 



The time of one oscillation being about lo seconds, the observer commenced at lo seconds 

 of the recorded time, and noted the scale reading at the end of the oscillation then occurring* 

 whether left or right ; then the opposite extreme reading of the following oscillation. The 

 recorded time is, therefore, within 5 seconds of the time corresponding to the mean reading. 



During magnetic disturbances the ten-second oscillation sometimes disappeared and the 

 scale appeared motionless for ten seconds or more. This is indicated in the original by the 

 remark " Quiescent," but in the published record it is shown by identical readings, scale right 

 and left. Again during these disturbances the scale occasionally moved steadily and slowly 

 (recorded "slowly decreasing" or " slowly increasing") for 10 or even 60 seconds, and the 

 record then shows the division that transited at the recorded time. Where the note "slowly 

 increasing" appears in record, the reading, as tabulated on pages 41 «/ seq., is followed by the 

 letter a, thus : 25.8a; where the note "slowly decreasing" appears in record, the tabulated 

 reading is followed by the letter b, thus : 2S.U. As the observer had to glance at the watch 

 in this case, the observation may be in error 5 seconds of time. 



Axis Observations 

 Observations for axis were made immediately before and after the declination observation 

 for the day, unless the disturbances were too great. Magnet No. 4, used in declination read- 

 ings, is cylindrical, requiring some two minutes to place the scale truly horizontal. It was 

 considered advisable to make these axis observations as rapidly as possible, owing to the fact 

 that the changes in declination do not, in general, vary uniformly with the time, even over the 

 short interval (sixteen minutes) usually consumed in making axis observations (United States 

 Coast and Geodetic Survey method) . Accordingly in the three positions of the scale £, I, E, 

 or /, E, I, the ends of consecutive oscillations were read as soon as the magnet was made 

 nearly stationary instead of waiting for consecutive two-minute periods. Even then some 

 very discordant results were obtained, and these have been arbitrarily rejected, and the mean 

 of the remaining results for the week ending Sunday 8 A. m. are the values used in the final 

 reductions. The values adopted at Teplitz Bay are shown in the following tabulation : 



