320 



CARNEGIE INSTITUTION OF WASHINGTON. 



were observed at sea, besides carrying out an elaborate program of 

 observations in atmospheric electricity. Observations for determina- 

 tion of the amount of atmospheric refraction have been continued, as 

 also the usual meteorological observations. 



Table 1 contains a summary of the magnetic declinations and chart 

 corrections observed on the Carnegie from Brooklyn to Dutch Harbor, 

 Alaska, during the period March-July 1915. It will be seen that there 

 is a steady improvement in the nautical charts since the data obtained 

 during the past cruises of the Galilee and the Carnegie became available 

 to hydrographic bureaus. The chart corrections, shown in the table, 

 reach a maximum value of about 1?5 in the region of the Pacific, 

 between Panama and Honolulu, not previously covered by these 

 vessels. For a general summary of the results in the Pacific Ocean, 

 obtained during the period 1905-1915, see abstract, pages 331-334. 



Table 1. — Magnetic declinalions and chart corrections observed on the Carnegie from Brooklyn, 

 New York, to Colon, Panama, from Balboa, Canal Zone, to Honolulu, and from Honolulu 

 to Dutch Harbor, Alaska, March-July 1916} 



Observers: J. P. Ault, commanding the Carnegie, H. M. W. Edmonds, I. A. Luke, H. F. Johnston, 

 and H. E. Sawyer. Minus sign indicates west declination, and plus, east declination. 



»For previous tables, see Terr. Mag., vol. 15. pp. 57-82. 129-144; vol. 16, pp. 133-136; vol. 17, 

 pp. 31-32, 97-101. 141-144, 179-180; vol. 18, pp. 63-64, 111-112. 161-162; vol. 19, pp. 38. 126, 

 204, 234-235. 



»From British Admiralty Chart No. 2598 for 1912, referred to 1915, 



'From Reichs-Marine-Amt chart No. 383, Tit. xiv. No. 1, for 1915, and Tit. xiv. No. 2, for 1910, 

 referred to 1915. 



*From lines of equal magnetic declination for 1915 on U. S. Pilot Chart No. 1400 of North 

 Atlantic, and on U. S. Pilot Chart No. 3500 of the Central American Waters, and from U. S. 

 Hydrographic Office Chart No. 2406 for 1910, referred to 1915. 



•From United States Isogonic Chart of the West Indies for 1915. 



