152 Land Magnetic Observations, 1914-20 



sity. The interior of Angola is a plateau of considerable elevation where the weather is 

 cold from April to August and at least 3 blankets are necessary, besides a supply of heavy 

 clothing. A rifle and revolver are required for protection, not against the natives who 

 gave no trouble, but against lions. Food generally is scarce in Angola and supplies must 

 be brought from the coast. A water cask or water bag should be carried, for water is 

 scarce in places. The Portuguese paper money (there is no silver or copper coinage in 

 circulation) is accepted even in the most remote parts, though salt or calico are appre- 

 ciated more. Fever and veldt sores appear to be the chief ills of the white man, and quinine 

 should be taken every day (5 grains or 25 grams) . A thorough survey of Northern Rho- 

 desia is being made, and the survey sheets can be procured on application to the Survey 

 Department at Livingstone. 



G. F. Dodwell, on Magnetic Work in South Australia, 1914 to 1918. 



In 1914 arrangements were made by which the cooperation of Government Astron- 

 omer G. F. Dodwell was secured in extending the magnetic survey in parts of South 

 Australia. In accordance with this arrangement magnetic observations have been made 

 in different parts of the state by expeditions sent out by the South Australian Government 

 primarily for other purposes. 



The Musgrave Range Geological Survey Expedition 1 offered an excellent opportunity 

 of obtaining a valuable series of magnetic observations in a part of the state not readily 

 accessible, and it was accordingly arranged that the Government Astronomer should 

 accompany the expedition during the second half of the journey, and should carry out 

 a program of magnetic work supplementary to the general magnetic survey of Australia 

 being carried out by the Department of Terrestrial Magnetism. The instrumental outfit 

 for this work consisted of magnetometer No. 6, provided by the Department, Barrow dip 

 circle No. 38, loaned by the Government Astronomer of New South Wales, a theodolite- 

 compass for quick determinations of declinations, besides various astronomical instru- 

 ments, barometers, thermometers, and miscellaneous accessories. The expedition left 

 Adelaide in August 1914, and returned in December of the same year. Complete obser- 

 vations were made at stations Nos. 1 to 9 in Table 20. 



The country traversed was very drought-stricken, most of the creeks not having 

 run for the past 7 years. The scarcity of water hampered the expedition a good deal, 

 so that the number of stations at which it was possible to obtain magnetic observations 

 was smaller than had been anticipated. Cautionary warnings regarding the natives had 

 been given, but no mishap or trouble occurred. Musgrave blacks had attacked previous 

 expeditions, but during this one they had been driven back farther than usual by the 

 drought. 



In addition to the 9 complete stations, declinations were obtained at 20 places en 

 route, using a trough compass-theodolite to which a solar attachment had been added, 

 making it essentially a small equatorial instrument mounted on a theodolite base. This 

 furnished a ready means of determining the meridian by pointing on the Sun, the declina- 

 tion then being obtained directly by the compass. The constant of the instrument was 

 obtained from time to time by comparisons with the magnetometer. The errors of 

 determination may be great, possibly amounting in some cases when the conditions were 

 unfavorable to as much as one-half degree; the observations are, nevertheless, useful 

 in showing that no great magnetic disturbances exist. Reports of other expeditions 

 indicate the existence of highly magnetic rocks in certain localities, but none was found 

 along the track of this expedition. The results of the compass observations are given 

 in detail in Table 19. 



During the years 1915 to 1918 the Government Astronomer made several journeys 

 to points within 200 miles of Adelaide for the purpose of determining latitude and longi- 



1 Seo Bulletin No. 5, Appendix 11, Geological Survey of South Australia, Adelaide 11)1.5. 



