258 CARNEGIE INSTITUTION OF WASHINGTON. 



of Magellan. Observer J. M. McFadden left Washington the middle 

 of September to report for duty on the Carnegie at Buenos Aires. 



The ship's personnel during November 1916 to October 1917, was 

 as follows: J. P. Ault, magnetician and in conmiand of vessel (to June 

 1, 1917) ; Dr. H. M. W. Edmonds, magnetician and surgeon and second 

 in command (to June 1, 1917), in command (from June 1, 1917); A. 

 D. Power, B. Jones, L. L. Tanguy, and J. M. McFadden (from October 

 1917), observers; N. Meisenhelter, stenographer-recorder; A. Beech, 

 first watch officer; M. G. R. Savary, engineer; L. Larsen and A. 

 Erickson, second and third watch officers, respectively; C. Heckendorn, 

 mechanic; 8 seamen, 2 cooks, and 2 cabin boys; the complete personnel 

 at any time consisting of 23 persons. 



For an account of the atmospheric-electric work aboard the Carnegie 

 see pages 253 and 254. 



Table 2 contains the preliminary results of Ocean Magnetic Observa- 

 tions on the Carnegie from San Francisco to Easter Island and Buenos 

 Aires, November 1916 to March 1917. This table supplements the 

 preliminary results for Cruise IV of the Carnegie, March 1915 to Sep- 

 tember 1916, pubhshed in Volume III (Researches of the Department 

 of Terrestrial Magnetism), pages 286-293. Since Cruise IV was com- 

 pleted at Buenos Aires on March 2, 1917, the results, sufficiently ac- 

 curate for all practical purposes, are now in print for the entire cruise. 

 While these preliminary results are subject to future revision, it is not 

 probable that there will be many cases in which the values of declina- 

 tion, or of inchnation, will be changed by more than 0?1, and the values 

 of the horizontal intensity by more than 0.001 c. g. s. 



The chart corrections for the principal charts in use are likewise 

 given in Table 2. Before deriving them, the values of the magnetic 

 elements as scaled from the various charts were referred to the date of 

 the Carnegie observations with the aid of whatever annual-change data 

 were given on the charts; the chart corrections as tabulated are thus 

 affected in part by errors in the pubhshed annual changes. On the 

 avei'age, the declination corrections are smallest for the very recent 

 British Admiralty charts (1917), in the construction of which all the 

 values of the Galilee and the Carnegie contained in Volume III were 

 available. 



