3i8 



SCIENTIFIC RESULTS OF ZIEGLER POLAR EXPEDITION 



The following monthly mean values for the logarithm of the magnetic moment of magnet 

 No. 4 at 20° Centigrade {m.J and for magnetic horizontal intensity {H) result from these 

 observations : 



The above mean values of H, each being made up of determinations made at different 

 times on the days of observation, may be taken practically as applying to mean of day. As 

 will be noted, the difference between the extreme values is but sixty-five gammas, which, con- 

 sidering the frequent and rapid fluctuations of this element in high latitudes, is quite satisfac- 

 tory. From the fifty-six determinations as grouped together in the above tabulation the 

 resulting horizontal intensity at Teplitz Bay is 



6768 r for epoch J904.J6. 



Secui,ar Changs in Magnetic Horizontai, Intensity 



Observations were made for horizontal intensity, as noted in the tabulation of results, at 

 the magnetic station of the Italian Expedition of 1899 and 1900. Unfortunately opportunity 

 was afforded only upon this one occasion for observation there. The value obtained seems 

 somewhat unsatisfactory in view of the unusually low value of the magnetic moment of magnet 

 No. 4 resulting. A close inspection of the observational data does not, however, disclose any 

 irregularities of greater amount than the similar work at the hut indicates should be expected 

 in this region. It is furthermore confirmed in that the result given is derived from two sets of 

 deflection as well as oscillation observations. 



For the purpose of reduction to mean of day a mean curve for diurnal variation in 

 magnetic horizontal intensity was deduced from the International Observations of 1882 to 1883 

 at the stations Ssgastyr, Siberia ; Cape Thordsen, Spitzbergen ; Jan Mayen Island ; Karmakul 

 Bay, Novaia Zemlia, and Bossekop, Norway. Applying diurnal variation corrections so 

 obtained, the determination at the Italian station on June 28, 1904, becomes 6810 j' + 50 ;- = 

 6860 Y. The nearest corresponding observation at the Ziegler Expedition station in point of 

 time (being but four hours before) is that of the preceding date ; reduced for diurnal variation, 

 the resulting value is 6784 >- + 8 r = 6792 y- From these two determinations it appears that 

 the horizontal intensity at the Ziegler Expedition station is about 68 y smaller than at the 

 Italian station. 



