SIR DAVID GILL— EDDIKGTOiT. 521 



by the various parties of observers; and, indeed, these geodetic re- 

 sults proved to be the most important outcome of the whole work. 

 Gill's share was a chain of telegraphic longitudes connecting Berlin 

 with Malta, Alexandria, Suez, and Aden, Before returning home he 

 proceeded to Egypt, in response to an invitation from Gen. Stone, 

 chief of the military staff of the Khedive, in order to measure a base 

 line for the proposed survey of the country. This work made slow 

 progress at first, as Gill had no trained assistance on which he could 

 rely; but in the end, with the help of Prof. Watson, he carried it 

 through satisfactorily. No permanent outcome of this work has 

 survived, for the defining marks of the base line were afterwards 

 destroyed by Arabs, 



It would serve little purpose here to enter into the details of the 

 work which Gill succeeded in accomplishing in South Africa, Be- 

 sides the more practical uses of an accurate survey, Gill kept ever in 

 view the object of the ultimate measurement of the great arc of the 

 meridian of 105° from the North Cape to Cape Agulhas — the long- 

 est measurable arc of the meridian in the world. Colonial and for- 

 eign Governments, the Chartered Company, and the scientific socie- 

 ties were all in turn pressed and persuaded. Difficulties of funds, 

 of personnel, of war, interposed obstacles; but there was no resisting 

 Gill. His indomitable persistence always won in the end. Worried 

 ministers would ultimately come to terms with their genial perse- 

 cutor. Still active in this great cause after retirement from the 

 Cape, he had the satisfaction of getting the last link of the South 

 African chain filled in. The great measured arc along the meridian 

 of 30° E. now extends from Cape Agulhas to within a short distance 

 of Lake Tanganyika, near the boundary of British territory, a 

 length of 24°, at which point it awaits the other chain of triangida- 

 tion that will some day be pushed clow^n from Egypt. 



We have now passed in review- the most important of Gill's scien- 

 tific investigations. To these may be added some miscellaneous 

 contributions, of which w^e can not here give any detail. A triangu- 

 lation by heliometer of the southern circumpolar stars was made 

 under his direction in 1897-1900, but he was not very satisfied with 

 the consistency of the observations. A series of meridian observa- 

 tions of the lunar crater Mosting A, organized by him jointly with 

 Sir William Christie at Greenwich, led to a good determination of 

 the lunar parallax and figure of the earth.* The arrangements for 

 a catalogue of zodiacal stars were placed in his hands by the Inter- 

 national Astrographic Congress. 



In October, 1906, Sir David Gill left the Cape. Owing to ill 

 health he had anticipated by rather more than a year the date of 

 compulsory retirement. But there were no signs of failing vigor 

 when he returned to England; on the contrary, he plunged into a 



