Comparisons of Magnetic Standards, 1915-21 



431 



1 All values are referred to A'; A' = B + 1'.3. 



2 The observations with the 2 instruments on February 17 and 18 were simultaneous, Mr. Evans observing the first 

 and second sets and Mr. Jeffries the third set with No. 71. Mr. Brown used both instruments on February 19 observing with 

 each alternately. 



SUMMARY. 



Table 8D summarizes the chief results as already published in Volume 11 and as 

 given above. 



Table SD. Summary of Corrections on Standards for Hongkong Observatory. 



Hence we obtain weighted mean values as follows : 



(8) I. M.S. -Hongkong (Elliott magnetometer No. 55) = +0'.9 (1908-1915). 

 (8a) I. M.S. -Hongkong (Elliott magnetometer No. 55) = +0.00109/7 (1907-1915). 

 {8b) I. M.S. -Hongkong (Dover dip circle No. 71, needles 3 4, 7.8)= -0'.8 (191 1-1915). 



NO. 9. HONOLULU OBSERVATORY, HAWAII. 

 Series I, 1915. 



Comparison observations were obtained during May 27 to June 22, 1915, by the 

 Carnegie party at the Honolulu Magnetic Observatory near Sisal, Oahu Island, Hawaii. 

 This observatory is operated by the United States Coast and Geodetic Survey. Three 

 stations were occupied: Absolute Observatory, the pier in the absolute observatory regu- 

 larly used for absolute work; A, 18.46 meters due north of the station Absolute Observa- 

 tory and 6.4 meters beyond a stone fence surrounding the Observatory inclosure, and B, 

 12.50 meters south 32. 7 west of the southwest corner of the absolute observatory and 

 18.01 meters east 1.2 south of the southeast corner of the entrance-vestibule of the 

 variation-observatory building. When C.I.W. earth-inductor No. 3 was used at the 

 station Absolute Observatory, it was mounted on a framework 20 cm. above the center of 

 the pier since, for this instrument, the rotating device for the coil requires a free space 

 below the instrument. It has been assumed that for this change in elevation there is 



See Res. Dep. Terr. Mag., Vol II, pp. 238-240. 



