278 CARNEGIE INSTITUTION OF WASHINGTON. 



has been accomplished during the current year by conscientious and 

 zealous performance of duties assigned (see pp. 286-29 0) . Reference to 

 plate 1 will also be found of interest. By following on the map the 

 ocean track marked VI, it will be seen how satisfactorily large gaps in 

 our ocean work are being filled in and how much useful information 

 respecting the changes in the Earth's magnetism is being secured by 

 the frequent intersections of the present cruise with the previous ones. 



Considering the difficulties of operating a ship under the present 

 adverse conditions, especially one engaged in scientific work, the success 

 of the Carnegie must be regarded as specially gratifying. It has again 

 become possible to supply establishments engaged in the preparation 

 of the magnetic charts used by mariners with the principal results of 

 the Carnegie's observations within two or three months after they 

 have been made. Tables of these results up to August 31, 1920, or 

 up to the Carnegie's arrival at Fremantle, will be found sununarized 

 on pages 310-311. 



The ports and dates of arrival will serve to indicate in a general way 

 the portion of Cruise VI accomplished during the present year : Dakar, 

 Senegal, November 24, 1919; Buenos Aires, January 19, 1920; James- 

 town, St. Helena, March 27; Cape Town, April 24; Colombo, Ceylon, 

 June 30; Fremantle, August 31, and Lyttelton, New Zealand, Octo- 

 ber 20. The length of the cruise from Washington to Lyttelton is about 

 34,000 nautical miles, which, added to the total length of the cruises, 

 1909-1918, 189,176 miles, gives an aggregate length of the Carnegie's 

 cruises, 1909-1920, of about 223,176 nautical miles, or about 256,998 

 statute miles. Combined with the cruises of the first vessel, the char- 

 tered Galilee, 1905-1908, 63,834 nautical miles, gives a grand total of 

 our ocean cruises, August 1905 to October 1920, 287,010 nautical miles, 

 or 330,506 statute miles, which is somewhat over 13 times the Earth's 

 circumference, and exceeds the mean distance of the Moon from the 

 Earth by about 92,000 miles, or nearly three times the Earth's cir- 

 cumference. (For a summary of the Pacific Ocean work prepared for 

 the First Pan-Pacific Scientific Congress at Honolulu, see p. 316.) 



OCEAN ATMOSPHERIC-ELECTRIC WORK. 



Investigations concerning the electrical state of the atmosphere over 

 the oceans have been successfully resumed on the Carnegie. Daily 

 observations are made of the potential-gradient, ionic content, con- 

 ductivity, penetrating radiation, and radioactive content of the 

 atmosphere. In addition, diurnal-variation observations consisting of 

 hourly observations for 24 consecutive hours are made at least twice 

 per month for as many of the elements as possible, usually potential- 

 gradient, ionic content, and penetrating radiation. Meteorological 

 observations are also made to accompany the foregoing in order to fur- 

 nish data for a study of their interrelations with atmospheric-electric 

 phenomena. 



