286 CARNEGIE INSTITUTION OF WASHINGTON. 



DETAILS OF OBSERVATIONAL WORK. 

 OCEAN-SURVEY WORK.i 



After sailing from Washington on October 9, 1919, the Carnegie 

 proceeded down the Potomac to Chesapeake Bay, where the usual 

 "swinging-ship" operations were carried out on October 11. The 

 vessel then proceeded to Solomons Island, where simultaneous obser- 

 vations of the potential-gradient of atmospheric electricity were carried 

 out on board and on shore, with the vessel's sails in the various posi- 

 tions occupied during observations at sea. Here the Director of the 

 Department joined the vessel for a final inspection. Upon the comple- 

 tion of the atmospheric-electric work, the Carnegie sailed for Old 

 Point Comfort, where the Director bade farewell to the party. Mr. 

 J. A. Fleming, chief of the Magnetic Survey Division, and Dr. S. J. 

 Mauchly, chief of the Section of Terrestrial Electricity, left the vessel 

 to return to Washington after all matters in their respective charges 

 had been arranged. 



After a few days' delay at Old Point Comfort, during which a 

 steward was signed on and seven seamen were replaced, the Carnegie 

 finally sailed from Hampton Roads, bound for Dakar, Senegal, on 

 October 19, 1919. 



Soon after leaving Old Point Comfort the vessel encountered the 

 usual Gulf-Stream weather, consisting of heavy winds from various 

 quarters, accompanied by rain-squalls and wet weather. Similar 

 weather continued all the way to Dakar, with only a few pleasant days 

 intervening. Two heavy storms were encountered, but no damage 

 was done to the vessel. Upon approach to the African coast, the usual 

 northeast trade wind was replaced by winds from the southwest to 

 southeast, making it necessary to keep well to the eastward in making 

 the approach to Dakar. During the four days before arrival at Dakar 

 heavy easterly winds, the harmattan, blew fine sand from the African 

 desert and moisture forming about the dust-particles developed into 

 a fog which obscured the Sun while below 10° to 15° of altitude. At 

 the same time the horizon was nowhere more than one-half mile 

 distant, which made navigation extremely uncertain and the approach 

 to land particularly hazardous. Altitudes of the Sun were measured 

 from a position as near the sea-surface as possible and were then cor- 

 rected for an estimated distance of the horizon. In spite of these 

 uncertain conditions, the landfall was made as expected, and after 

 standing off and on for 36 hours the Carnegie entered the harbor of 

 Dakar under her own power when the haze lifted for a few hours on 

 November 22, 1919. 



' From Commander J. P. Ault's reports. 



