Reductions to Standard Instruments 69 



The adopted logarithms of the total-intensity constants resulting from least-square 

 adjustments of all available data are given in Table 15. 



Table 15. — Intensity Constants for Sea Dip-Circle 169. 



Number of- 



Suspended 

 Needle 



Deflecting 

 Needle 



Deflection 

 Distance 



No. of 



Weight in 



Loaded 



Needle 



Logarithms of Intensity Constants 



For observations during Cruise I 



4 

 3/) and R 

 4 



3D 

 3fl 

 3D 

 3fl 



One only- 



One only 

 One only 

 One only 

 One only 



^C = 9 . 50920 during Aug. 2 to 23, 1905' 



Ci = 9.41866 - 0.00012 (20°- () from Aug. 24, 1905' 



Ctf = 9.60033 + 0.00012 (20 - () during Aug. 24 to Sept. 14, 1905' 



Ci = 9.60238 + 0.00012 (20 - () during Aug. 24 to Sept. 14, 1905' 



Ci = 9.59564 + 0.00012 (20 - () from Nov. 18, 1905' 



Ci = 9.59821 + 0.00012 (20 - () from Nov. 18, 1905' 



For observations during Cruise III; At = (x — 1908.00) 



8 



7D 



7/J 



7D 



7R 



Short 

 Short 

 Long 

 Long 



31 



C, = 9.67097 + 0.01204 At + 0.00566 (At)' - 0.00010 (20°- 

 Ci = 9.50033 - 0.00794 At - 0.00222 (At)' + 0.00010 (20 - 

 Ca = 9.50129 - 0.00794 At - 0.00222 (At)' + 0.00010 (20 - 

 Ca = 9.35638 - O.OOSIO At - 0.00379 (At)' + 0.00010 (20 - 

 Ct = 9.35722 - 0.00810 At - 0.00379 (At)' + 0.00010 (20 - 



'Values of H computed by these constants were reduced to C. I. W. Standard (see p. 77) by applying a correction of -0.00047//. 



Sea dip-circle 189.— Sea dip-circle 189, of the improved type and provided with 

 arrangements for two deflection distances (see p. 22), was used during Cruise III, beginning 

 at Sitka, August 1907. The adopted formulae resulting from least-square adjustments of 

 all available data for corrections to observed inclinations are given in Table 16. 



Table 16. — Inclination Corrections for Sea Dip-Circle 1S9. 



The adopted half polarity-differences, determined from gi-aphs based on all available 

 data, are given in Table 17. 



Table 17. — Half Polarity-Differences for Sea Dip-Circle 189. 



