MAGNETIC OBSERVATIONS. 



77 



Scale Readings. 



Mean local 











time. 



Febraary 11-12. 



February 18-19. 



February 25. 



March 4^5. 



8 A.M. 



34''. 3 



R. 



34^6 



K. 



-36^8 



S. 



39M 



R. 



9 " 



36.9 





35.9 





35.4 





38.1 





10 " 



36.7 





36.5 





35.1 





37.7 





11 " 



31.1 





36.1 





35.3 





37.8 





Noon 



3T.3 





Instrument moved 



36.8 





35.4 





1P.M. 



33.9 



S. 



31.0 



R. 



37.0 



K. 



35.9 



S. 



2 " 



35.8 





30.1 





38.3 





35.1 





3 " 



36.Y 





33.3 





37.1 





35.0 





4 " 



35.1 





35.8 





35.8 





35.2 





5 " 



36.0 



K. 



35.1 



S. 



38.6 



R 



36.8 



K. 



6 " 



38.6 





35.2 





38.5 





38.1 





1 " 



38.3 





37.3 





38.7 





38.5 





8 " 



39.0 





37.8 





38.8 





38.0 





9 " 



38.8 



R. 



37.9 



K. 



38.8 



S. 



39.3 



R. 



10 " 



39.7 





37.4 





38.7 





39.2 





11 " 



39.3 





38.6 





38.6 





38.9 





Midnight 



41.6 





40.3 









39.5 





1A.M. 



43.1 



S 



37.2 



R. 







39.1 



S. 



2 





39.9 





36.6 









39.3 





3 





39.8 





36.5 









39.4 





4 





36.6 





36.7 









38.5 





5 





38.3 



K. 



37.0 



S. 







37.2 



K. 



6 





38.0 





36.2 









38.1 





t 





37.4 





35.5 









38.5 





8 " 



35.9 





33.0 









38.8 





Circle Readings. 





8 A. M. 26° 20' 



8 A.M. 



26° 20' 



8 A. M. 26° 20' 



8 A. M. 26° 20' 





Light wind and snow 



1 P. M. 



" " 



Wind blowing heavy 



Clear, with wind from 





from S. W. (true) 



Calm and clear dur- 



from N. (true), 



N. E. (true) dur- 





until 8 P. M., when 



ing the above ob- 



and snow drifting. 



ing the above ob- 





the wind blew 



servations. 



Observations dis- 



servations. 





stronger and snow 





continued at 11 







drifting. 





P. M. on account 

 of wind. 





"We have now to express the preceding nmnbers in units of the same scale, and 

 to refer them to the same zero for each day. The determination of the scale value 

 at Washington gave 1 division = 10'. 14 since in the present record the last figure 

 is noted as a decimal. The given reading of the circle is taken to refer to the 

 centre of the reflected scale or to the division 30, the excess above 30 converted 

 into parts of a degree, has been added to the circle reading and the defect below 

 30, after conversion, has been subtracted from the circle reading, the latter being 

 expressed in degrees and fraction of a degree. 



Inci'easing scale numbers correspond to an easterhj movement of the north end 

 of the magnet ; increasing circle readings are likewise in the direction from north 

 to east. The correction for torsion (for deviations beyond 30.0 divisions) lias been 

 rejected by the observer as too small to affect the results. 



