Appendix III. 

 MAGNETIC OBSERVATIONS. 



BY 



HARRY FIELDING REID. 



The instruments for this work were supplied by the United States 

 Coast and Geodetic Survey. They were a small magnetometer, known 

 as the Bache Fund magnetometer ; a dip circle (number 12) of about 12^^ 

 diameter ; and a mean time chronometer. 



The magnetometer was not adapted for determining the magnetip 

 moment of the needle ; and as this was not done until some time after 

 my return, the resulting value of the intensity cannot be considered very 

 accurate. The moment of inertia was, however, detei'mined in the field. 

 JJ is given in c-g-s units [i.-e., in centimetre-gramme-seconds). 



Special tents wei-e erected for the instruments. The magnetometer was 

 85 yards and the dip circle 65 yards from our tents. During the observa- 

 tions with the former, the latter was about 100 yards distant. 



* The negative sign means that the north end of the needle points to 

 the east of astronomical north. 



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