56 EEPORTS ON THE STATE OF SCIENCE, 



Geodetic Arc in Africa. — Jxeiwrt of the Committee, consisting of Sir 

 Geoege Darwin (Chairman), Sir David Gill (Secretary), Major 

 C. F. Close, ami Sir George Taubman Goldie, appointed to 

 co-operate in the Measurement of a further portion of the Geodetic 

 Arc of Meridian North of Lalce TanganyiJm. (Draum up hij the 

 Chairman.) 



On May 7, 1907, Sir David Gill, Sir George Goldie, and Sir George 

 Darwin wrote a joint letter to the Secretary of State for the Colonies 

 suggesting that advantage should be taken of the presence of a Boundary 

 Commission in Uganda to measure a further portion of the arc of 

 meridian of the 30 th degree of east longitude, and offering, on behalf of 

 the Royal Society, the Royal Geographical Society, the Royal Astro- 

 nomical Society, and the British Association, to contribute the sum of 

 1,000Z. towards the cost of the work. 



This Committee was appointed at the meeting of the Association lield 

 at Leicester. 



On August 5 and August 20 the Secretary of State wrote to Sir David 

 Gill agreeing to the proposal, and offering the post of skilled observer to 

 Mr. G. T. McCaw. 



On September 4 the Foreign Office suggested to the Government of 

 the C-^ngo Free State the desirability of their co-operation. This was 

 agreed to on December 13, and that Government agreed further to send 

 and pay for a skilled observer, namely, M. Dehalu, of Liege. 



It was agreed that the whole operation of measuring the arc should 

 be under the joint control of the Boundary Commissioners. 



Technical instructions were handed to Mr, McCaw on his departure 

 from England, and he arrived at Toro, a point on the arc, on March 14, 

 1908, having with him all his instruments. He was joined by M. Dehalu 

 at Toro on April IG, 1908. 



The state of the work, as described in letters from Colonel Bright, 

 the officer in charge of the Boundary Commission, and from Mr. McCaw 

 on May 9, was as follows : — 



The arc-measuring party consists of Captain Jack, R.E. ; Mr. 

 McCaw ; two British non-commissioned officers ; one Belgian officer ; and 

 M. Dehalu. 



The preliminary reconnaissance of the arc from Lake Albert to 1° of 

 S. latitude had been completed by the Commission. The final recon- 

 naissance of two figures had been completed and six stations had been 

 built. The base had been selected and marked and observations at one 

 station had been completed. 



On the annexed map the portion of the survey, for which the stations 

 are built and the corresponding triangles measured, are shown with firm 

 lines. The proposed triangles for the rest of the arc are shown in dotted 

 lines. 



The information contained in this report has been furnished by thp 

 Wfir Office through Major C. F. Close, R.F,. 



