232 HEADQUARTERS OF SURVEY DEPARTMENT. 



(5.) Turkestan. Scale, 32 inches = 1 mile. 6th edition. Photo- 



zincographed, in four sheets. 

 (6.) Afghanistan. Scale, 24 miles = 1 inch. Photo -zincographed, 



two colours, in four sheets. 

 (7.) Burma and Adjacent Countries. Photo-zincographed. 



Scale, 32 miles = 1 inch. 

 (8.) Atlas of India. Scale, 4 miles = 1 inch. Engraved. 

 (9.) Provincial maps. Engraved on the scale of 16 miles = 



1 inch. 

 (10.) Standard sheets of the Topographical and Revenue Surveys 

 on various scales from 2 inches = 1 mile to 4 miles = 

 1 inch. 1 inch = 1 mile is the standard. 

 (11.) District maps on various scales, usually 4 miles = 1 inch. 



Transferred to stone from the engraved copper plates. 

 (12.) Himalayan Route map. Scale, 32 miles — 1 inch. 



Engraved. 

 The Trigonometrical Branch Office, Dehra Dun. — Although the 

 three branches of the Survey (Trigonometrical, Topographical, and 

 Revenue) were amalgamated in 1877, it was nevertheless found 

 convenient to maintain the Trigonometrical Survey Office at Dehra 

 Dun, where important and special work had and still has to be 

 transacted. The principal part of this work has been the final 

 reduction and publication of the Indian and extra-Indian triangula- 

 tion, both principal and secondary, which was carried out for years 

 under the care of Mr. J. B. N. Hennessey and Mr. W. H. Cole. This 

 Department Las also had to publish the Topogi'aphical Surveys 

 executed by the parties formerly attached to the Trigonometrical 

 Branch, as well as those carried out by the Forest Survey Depart- 

 ment. Being located at a considerable distance from Calcutta, 

 the office has a small drawing, photo-zincographic, and printing 

 establishment of its own. as well as a depot of instruments and stores 

 attached to it, chiefly of the higher class of instruments appertaining 

 to the Great Trigonometrical Survey, such as several large theodo- 

 lites, the compensation bars, and apparatus for the measurement of 

 base-lines. &c. Other work pertaining to this branch has consisted 

 in the determinations of azimuths from celestial observations at many 

 of the stations of the triaugulation ; the observations of astronomical 

 latitudes, the determination of differences of longitude by the aid of 

 electric telegraph, and the determination of sea-level at many places 

 on I lie coasts of India, from which main lines of spirit-levelling are 



