Comparisons of Magnetic Standards, 1905-14 



269 



'See Tables 27 A, 27 B, pp. 262-263, giving results of comparisons at Washington. 



The corrections accordingly adopted for C. I. W. magnetometer No. 5 for the observa- 

 tory comparisons referred to, were -f-O'.l for dechnation and 0.00090i7 for horizontal 

 intensity. The instrument unfortunately sustained a fall during the comparisons at 

 Washington upon Mr. Pearson's return in 1910, necessitating extensive repairs and altering 

 the constants. However, the various checks appUed (see, for example, Table 30 D) show 

 that, during the two years tliis instrument was used in field work of the most severe character, 

 its constants remained unaltered within the errors of observation. See also the results of 

 comparisons at the Kew Observatory (Tables 14 A, 14 B, p. 241), before and after this 

 field work. 



No. 31. VARIOUS ADDITIONAL OBSERVATORIES. 



During 1905-1907, comparisons were obtained by the observers of the Department of 

 Terrestrial Magnetism at the following adchtional magnetic observatories: Baldwin (Kan- 

 sas), Honolulu (Hawaii), and Sitka (Alaska). These observations were, however, pri- 

 marily intended to serve as a control on the constants of the instruments used in the mag- 

 netic survey work (chiefly the work of the Galilee in the Pacific Ocean). It might also be 

 remarked that the magnetic instruments at Baldwin, Honolulu, and Sitka are referred by 

 the United States Coast and Geodetic Survey to the standards of the Cheltenham Magnetic 

 Observatory, for which direct comparisons are given on pp. 226-229. 



During the period 1907-10, two important series of comparisons at certain magnetic 

 observatories in Europe and Asia were obtained bj^ observers of other organizations, the 

 results of which it will be desirable to include in this report. 



Table 31 A. Prdiminary Results of Comparisons between the Pavlovsk Magnetic Standards and Certain Observatory 



StaTidards. 



[The following series of comparisons was made bj' the Russian observers, Messrs. W. Dubinsky and S. Savinov, in 1907-08, 

 and referred by them to the magnetic standards (Declinometer, Wild-Freiberg magnetometer No. 1 and earth inductor) 

 of the Pavlovsk Magnetic Observatory, near Petrograd. Their results as published in W. Dubinsky's preliminary 

 report' have been modified here as follows: (a) the signs of the declination differences (AD) have been reversed in order 

 to correspond with east dechnation taken as positive; (h) the horizontal-intensity differences (AH) have been e.\pressed 

 in parts of H with the aid of the appro.Kimate value of // at the observatory compared.) 



'Bericht iiber die Versammlungen des Internationalen Meteorologischen Komitees uud dessen Kommission fur 

 Erdmagnetismus und Luftdektrizittit. VcrSff. Met. Inst., No. 227, BerUn, 1910, Anhang IV. p. 88. 

 'The figures after the number of dip circle designate the needles used. 



