xlv 



instruments, and a history of the pendulum observations which he 

 inaugurated, two convertible pendulums having been lent to him by 

 the Imperial Academy of Sciences of St. Petersburg. 



While Colonel Walker conducted, to the very best advantage, the 

 most intricate and exact measurements, he also took a broad-minded 

 view of the rougher systems of exploration and reconnaissance. 

 Primarily he was a geodesist, but he was also an enthusiastic geo- 

 grapher. Survey parties were, in his time, carefully organised to 

 accompany every military expedition. Native explorers were 

 trained as surveyors, and despatched into unknown parts of Central 

 Asia and Tibet. Their work was reduced, critically examined, and 

 utilised on their return. Numerous valuable general maps were 

 published at the office of the survey at Dehra Dun, and Walker's map 

 of Turkistan, which went through many editions, was the leading 

 authority for upwards of twentv years. Walker also established 

 friendly relations with the Russian surveying authorities, there was 

 an exchange of publications, India was well supplied with geo- 

 graphical information from St. Petersburg, and there was a cordial 

 feeling of co-operation between the surveying officers of the two 

 countries. During his short periods of leave in England, Colonel 

 Walker did not cease to work zealously for his department. On one 

 of these occasions he fixed the difference of longitude between 

 London and Tehran ; on another he investigated the condition of 

 the plates of the Indian Atlas, and wrote an important memorandum 

 on the scale of the atlas and on the projection. From 1878 Colonel 

 Walker undertook the onerous and difficult post of Surveyor- 

 General of India, in addition to his laborious and absorbing duties as 

 Superintendent of the Great Trigonometrical Survey. At last the 

 strain became too great. His health broke down, and although the 

 Viceroy was most anxious that he should remain, it became absolutely 

 necessary for him to leave India. He retired in 1883, and became a 

 General in 1884. 



In his retirement, General Walker continued to "live laborious 

 days." He conducted a large correspondence with geographers and 

 explorers, and with officers connected with geodetic surveys in various 

 parts of the world, always being ready to furnish all the information 

 and advice that his great experience could "suggest. He became a 

 Fellow of the Royal Society in 1865. He was also a very active 

 member of the Council of the Royal Geographical Society for upwards 

 of ten years, and wrote several valuable papers on subjects relating to 

 the geography of Central Asia and Tibet. He had a happy knack of 

 communicating his knowledge to others unostentatiously, and in the 

 most effectual way. His kindness and patience in this respect were 

 much appreciated by the officers who served under him. While he 

 raised the standard of high excellence of the geodetic work in India, 



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