186 Land Magnetic Observations, 1914-20 



will not go below Ibi, so I was compelled to wa it for the next steamer, which arrived 

 July 31, and Abinsi was reached August 3. Confirmation of the news of the declaration 

 of war was found in the crowded conditions of the boats, which made it difficult to secure 

 passage. Lokoja, at the junction of the Benue with the Niger River, was finally reached 

 on August 16. 



Ascending the Niger River in a steamer to Baro, I occupied a station there August 

 28, and returned to Lokoja. Continuing down the Niger, stops were made at Onitsha 

 and at Abo where I arrived October 1. The rains had greatly increased since leaving 

 Lokoja and the supply of boats diminished as the government was using them for the 

 transportation of troops to Yola and Garoua and for the operations against Douala. 

 No regular mail service was ma'n'ained. On October 30 the Forcados station was 

 occupied, and on November 5, I embarked for Plymouth en route to Washington. 



Table 29 (see p. 185) gives a list of the points occupied, together with dates and 

 geographical positions. The magnetic data for stations of 1913 are given in Volume II 

 of these Researches, and those for the other stations are given in the Table of Results in 

 the present Volume. 



The total time in obtaining the observations was 500 days, including 36 days' travel 

 to the Office, making an average of about 8 days per station. Approximately 6,000 miles 

 were covered by field traveling, of which one-third was railroad, one-third ocean, one- 

 fourth river, and one-twelfth bush travel. The average distance between stations is 

 about 100 miles. The average field expense was about $51 for a station. The actual 

 living expenses were very small in comparison with the cost of transportation. 



The success of the expedition was contributed to by the Lieutenant-Governor of 

 the Ivory Coast, who extended free transportation on the French government railroad 

 in that colony; also by the courtesies extended by Mr. Cleminson, Director of Cadastral 

 Surveys of the Southern Provinces, and Mr. A. S. Collard, Director of Survey of Northern 

 Provinces, Nigeria. 



H. E. Sawyer, on Magnetic Work in Southern, Central, and Northeastern Africa, 



December 1915 to December 1918. 



This expedition comprises preliminary work in Australasia, and a few stations in 

 Asia at the conclusion of the more extended travels in Africa along the entire length of 

 the continent from Cape Town to Suez. The more detailed narrative of the entire ex- 

 pedition is given under titles corresponding to the following brief outline: 



I. Preliminary observations in Australasia, including intercomparisons of instruments in New Zealand and 

 Australia before commencing the African work. 

 II. Repeat stations for secular variation in South and Southwest Africa, principally those of Dr. J. C. Beattie's 

 survey of South Africa, with others of the Department of Terrestrial Magnetism along the west coast 

 of Africa to the mouth of the Congo. 



III. The Gabon expedition, going overland from Stanley Pool on the Congo River to the head waters of the 



Ogoue River and down this river to the Atlantic coast at Libreville. 



IV. From the Congo to the Nile, going up the Ubangi River to Bangui, thence overland to the head waters 



of the Chari River, down that river to the region of Lake Tchad, and by caravan eastward across Dar 

 Massalit, Dar Fur, and Anglo-Egyptian Sudan to Khartum. 

 V. Along the Nile River and Red Sea coast, first ascending the White Nile from Khartum to Gondokoro, then 

 making an overland journey from Khartum to the Red Sea, concluding with a reoccupation of sta- 

 tions of the Egyptian Survey along the rail and river trip down the Nile to Cairo. 

 VI. Return to America via the Orient, going by way of the Suez Canal, Red Sea, India, and Japan, and 

 observing at repeat stations along the homeward journey. 



I. Preliminary observations in Australasia. Following the instructions dated Novem- 

 ber 5, 10, and 19, I was transferred from the Carnegie to land duty. Field work was 

 started upon the departure of the Carnegie from Port Lyttelton, December 6, 1915. 

 My outfit comprised theodolite-magnetometer No. 17; Dover dip circle No. 223, with 

 needles Nos. 1, 3, 5, 6; tripod; observing tent; kodak; and various other accessories. 



