DEPARTMENT OF TERRESTRIAL MAGNETISM. 243 



Washington, District of Columbia. — The investigations and control of 

 magnetic standards in the Standardizing Magnetic Observatory at Wash- 

 ington were continued throughout the year. Extensive series of comparisons 

 were made during February and March between sine galvanometer 1, standard 

 magnetometer 3, and magnetometer inductor 27, the last being the instru- 

 ment so extensively used for observatory comparisons in 1922 (see p. 279 

 of last year's report) . The results indicate that the provisional International 

 Magnetic Standard, adopted by the Department for horizontal intensity in 

 1914, is in substantial agreement with intensities determined electromag- 

 netically by the sine galvanometer (see p. 256) ; the 1923 results also confirm 

 the constancy of the adopted standard, as they are in practical agreement with 

 those obtained in June and August 1921.^ The 1923 series afforded also 

 an indirect comparison of standards with the Schuster-Smith magnetometer 

 (electromagnetic) of the National Physical Laboratory, Teddington, Eng- 

 land, and with the Watanabe electric magnetometer of Japan through the 

 comparisons with C. I. W. standardized magnetometers made by Messrs. 

 Parkinson and Brown in 1922 at Teddington and Kakioka. The results, 

 abstracted on page 257, furnish additional evidence of the constancy within 

 all practical and theoretical requirements of the Department's standard in 

 intensity. The compilations of the extensive comparisons obtained at 23 

 magnetic observatories in different parts of the world during 1922 were 

 finally completed and prepared for publication by Messrs. Fleming and Park- 

 inson. Further comparisons of standards were made in 1923 by Department 

 observers at the following observatories: Apia, Samoa; Batavia, Java; Huan- 

 cayo, Peru; Kakioka, Japan; Mount Lofty (Adelaide Observatory), South 

 Australia; Pilar and La Quiaca, Argentina; and Watheroo, Western Aus- 

 tralia. 



At its annual meeting in April 1923, the American Geophysical Union 

 passed the following resolution: 



"That the American Geophysical Union designate the Cheltenham Magnetic Observatory 

 of the United States Coast and Geodetic Survey and the Standardizing Magnetic Observa- 

 tory of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, 

 working in conjunction, as the observatories in the United States to function in accordance 

 with resolution No. 4 adopted by the International Section of Terrestrial Magnetism and 

 Electricity at its Rome meeting in 1922." " 



The experimental atmospheric-electric observatory on the deck of the Labor- 

 atory at Washington was continued in operation throughout the year (see 

 abstract of results, p. 265). 



Miscellaneous. — Besides the extensive cooperative work already men- 

 tioned elsewhere, the Department cooperated with Professor W. Uljanin, of 

 Kazan University, Russia, in his development of electromagnetic instru- 

 ments, supplying him with normal cells and standardization certificates from 

 the Bureau of Standards. 



Reduction of observatory records obtained at the Watheroo Magnetic Observa- 

 tory, 1919-21. — Dr. H. M. W. Edmonds, with the assistance since September of 

 Mr. W. F. Wallis, has completed about three-fourths of the final compilations 

 from the magnetic data for the Watheroo Observatory during the years 1919 

 to 1921. He also did some experimental work in the Laboratory at Wash- 

 ington to check the adopted formula for the scale-value for the declination 

 variometer (see p. 252). 



1 See Res. Dep. Terr. Mag., vol. iv, pp. 416-417. 



* "That national committees be requested to designate, if possible, one observatory in their 

 respective countries for international intercomparisons of magnetic instruments, and to secure 

 intercomparisons of magnetic instruments within their own countries at least once within the 

 course of three years." 



