SCIENTIFIC RESULTS OF ZIEGLER POLAR EXPEDITION 



Corrected distances on new brass deflection bar at o" Centigrade : 



r log r log J4t^ log C 



30.003 cm. I. 47716 4-13045 5.86889 



40.003 cm. 1.60209 4-50524 5-49441 



For an increase in temperature of 1° Centigrade log C decreases 0.000025 



One division of scale = i'.57 



Temperature coefficient : ^=0.00030 for i" Centigrade 



Induction coeffident : i" = 5.63 ; 



When r= 30 cm. log (i +-j J = 0.00018 

 = 40 cm. = 0.00008 



Distribution coefficient : /*=: — i.oo ; 



When r = 30 cm. log ( i 5 j = 0.00048 



These constants are adapted for the methods of computation in use by the Coast and 

 Geodetic Survey, where the following formulae are used in computing horizontal intensity : 



H C ^ 2 , 



log H= y^ (log — + log mfr^ . 



In these formulae, 



H = horizontal intensity 



m = magnetic moment of magnet 



T' = observed time of one oscillation corrected for rate of chronometer 



A = angle through which magnet is turned by turning the torsion head through an 



angle / 

 /' = temperature of oscillations 

 i = temperatpre'of deflections 

 u = deflection angle 



