COMPAKISONS OF MAGNETIC STANDARDS, 1915-21 



457 



intensity, and (N SE) = +0'.30'.2 for inclination, are so small and so little in excess of the 

 observational errors that they may be disregarded for absolute observations and comparisons. 

 Outside of the absolute observatory there are piers Na a (15 meters north of N), Ea (15 meters 

 east of N), and Wa b (15 meters west of iV). Three meters northwest of JV there stood in 1907 a 

 wooden stump, Ha. Stations Ha and E were removed before 1917." 



Table 16H summarizes the station-differences as given by Dr. Angenheister. 



Table 16H. Summary of Station-Differences at Samoa Observatory, 1905 to 1917. 



SUMMARY. 

 Table 161 summarizes the results as given above. 



Table 16 I. Summary of Corrections on Standards for Samoa Observatory. 



i See Table 16G. 



Hence, we obtain weighted mean values as follows: 



(16) I. M. S.-Samoa (Tesdorpf magnetometer No. 2025, magnet 12)= -3'.0 (1905- 

 1921). 

 (16a) I. M. S. Samoa (Tesdorpf magnetometer No. 2025, magnets 38 and 12) = 



+0.0001 1H (1905-1921). 

 (166) I. M. S.-Samoa (Schulze inductor No. 2) = +0'.7 (1905-1921). 



NO. 1 7. STONYHURST COLLEGE OBSERVATORY, STONYHURST, ENGLAND. 



The comparisons of 1915 were obtained for the Observatory by Reverend E. D. O'Con- 

 nor, S. J., under the direction of Reverend W. Sidgreaves, S. J., Director, and for the Car- 

 negie Institution of Washington by Observer E. Kidson. Two stations designated A and 

 B were used. Station A was the wood-topped, sandstone pier regularly used for abso- 

 lute observations in the magnetic hut by the Observatory. The tent station B was on 

 the Observatory lawn, 39 feet northeast of the northeast corner of the north room of 

 the main Observatory building, and 87.4 feet northwest of the west corner of an observ- 

 ing pier in the east corner of the lawn. At A, the Observatory azimuth mark, a cross 

 painted on a slate roof, was used; the true bearing of the mark, supplied by Reverend 

 Sidgreaves, was 337 03'. 3 west of south. At B, the left edge of the infirmary, about 

 800 feet distant, was used as an azimuth mark; its true bearing, determined by Observer 

 Kidson, was 125 57'.7 west of south. 



The Observatory absolute instruments used were a Kew-pattern unifilar magnet- 

 ometer by Jones, and Dover dip circle No. 159 with needles 1 and 2. The magnetom- 



" The station designated Apia, North Pier, on page 100 of Volume I, lies. Dep. Terr. May., is .W and not A'. 



6 Station W, is designated West Pier or W in the C. I. W. results given in Volumes I and II, Res. Dep. Terr Mag. 



