GREAT TRIGONOMETRICAL SURVEY OF INDIA. 45 



celebrated native explorers who have obtained so much new 

 geography in Trans-Himalayan regions. 



On being appointed Surveyor- General, Colonel Walker proceeded 

 to carry out the amalgamation of the three branches of the Survey 

 referred to above. 



Colonel "Walker held the Surveyor-Generalship until 1883, when 

 he was succeeded by Colonel George Charles De Pree. The latter 

 officer had entered Addiscombe in 1848, and was appointed Second 

 Lieutenant of the Bengal Artillery in 1850. He served with the 

 Pegu Field Force in the following year, and examined the Tonghup 

 pass between Arakan and Burma, and reported on its practicability 

 for elephants. For this he was thanked by Lord Dalhousie, the 

 Governor-General, and he also gained the Pegu war medal. In 

 1854 he joined the Survey Department and was deputed to take up 

 topography in Ganjam, where he worked for many years, being 

 afterwards attached to the contiguous survey of the Chota Nagpur 

 Division. On the disbanding of No. 4 Topographical Party (see 

 p. 74), he was placed in charge of No. 7 Party (Bajputana and 

 Simla). He officiated as Surveyor- General in 1883-84, and in the 

 latter year was confirmed in the appointment, which he held up to 

 his death, in Jersey, on the 18th February 1887. He was a talented 

 and indefatigable officer, and his early death was undoubtedly due 

 in great measure to the inclement and unhealthy tracts in the 

 eastern part of the Peninsula where he had so long and energetically 

 laboured. He was succeeded by Colonel H. P. Thuillier, R.E., (son 

 of the former Surveyor-General of that name) who obtained his 

 commission in 1857, and whose good services have admirably 

 sustained the traditions and reputation of the Department. 



During the year 1876-7, at which period our review of these 

 operations begins, three' parties were engaged on principal triangula- 

 tion, on the Madras Coast Series, the Eastern Frontier Series, 

 and the Eastern Sind Series, and two parties in the Assam Valley 

 and British Burma on secondary triangulation. The primary 

 object of the Madras Coast Series was the completion of the 

 principal triangulation in Southern India by a regular series between 

 Madras and Cape Comorin, with a branch series via Palk straits 

 connecting Ceylon with India. Triangulation had been carried into 

 this region by Colonel Lambton in the beginning of the century, 

 but on leaving the hills of the central peninsula and entering a 

 vast plain covered with trees and vegetation, it met with difficulties 

 which the early appliances of the survey were inadequate to 



