120 Land Magnetic Observations, 1905-10 



in Persia after leaving Teheran, i at Gwadur, Baluchistan, 4 in Arabia, i at Basra, Asia Minor, 

 20 in Asiatic Russia, and 11 in European Russia, as also a rcoccupation of the station at Con- 

 stantinople. June 28 to July 3, 1909, he once more compared his instruments at the Tiflis Mag- 

 netic Observatory and in the following September made comparisons of his instruments with 

 those of the Tashkent Observatory. After an expedition along the southern coast of the Black 

 Sea in Turkey in Asia, he returned to Constantinople. Upon completion at Constantinople of 

 comparisons with instruments brought from Washington by Observer W. H. Sligh, he returned to 

 Washington, March 26, 1910. On his homeward journey he obtained a valuable series of com- 

 parisons of the standards of the Department of Terrestrial Magnetism with those of the obser- 

 vatories at Pola, Potsdam, Kew (a second time), and Cheltenham, Maryland. 



Mr. Pearson, in addition to the observations at magnetic observatories, had determined the 

 magnetic elements at about 130 stations, in regions chiefly where no previous data had been ob- 

 tained; some of his stations were reoccupations and hence secular changes were also obtained. 

 Much delay ensued at times, caused by the unsettled political conditions in Asiatic Turkey and 

 Persia when the expedition was in progress; the various difficulties were, however, successfully 

 overcome. 



Acknowledgment is due the representatives of the Turkish, Persian, Russian, English, and 

 American governments for special courtesies extended, as also to General M. Rykatcheff, and to 

 the directors of the various observatories, where the intercomparisons were made. The treasurer 

 of the American Missions in Turkey, Mr. W. W. Peet, assisted in the transfer of funds to the party. 

 Mr. Dimiter V. Pehlivanoglou accompanied the expedition as interpreter and assistant. After 

 Mr. Pearson left the field, the work was continued by Mr. Sligh in European and Asiatic Turkey, 

 about 75 stations having been occupied by the end of 1910; some of these were repeat stations. 

 Mr. Sligh 's work is still in progress. 



E. Kidson. Before joining the Carnegie at St. Johns, Newfoundland, Mr. Kidson, in August 

 and September, 1909, determined the magnetic elements at I station in New Brunswick, i in 

 Nova Scotia, and 17 in Newfoundland, 4 of which were repeat stations. 



C. C. Stewart. Beginning in August, 1910, a valuable scries of magnetic stations was secured 

 along the Amazon and Ucayali Rivers using the launch El Imdn purchased by the Department 

 of Terrestrial Magnetism. The first station was at Manaos, Brazil, at which observations had 

 been made previously by others. About 21 stations were then occupied between Mandos and 

 Iquitos, Peru. From Iquitos the work was extended along the Ucayali River, observations 

 having been made at 12 stations, also at 3 in Peru, along the Maraiion River. The work was 

 continued in 1911. [This series of stations across South America was completed in 1912 by 

 Mr. H. R. Schmitt of Mr. J. P. Ault's party.] 



