Electro-telegraphic longitude operations executed during the years 1881-82, 1882-83 and 1883-84 /
Strahan, George,1839-
Heaviside, William James,1840-
Survey of India.Trigonometrical Branch.
Dehra Dun : Office of the Trigonometrical Branch, Survey of India,
1887 .
India. Great Trigonometrical Survey.
Longitude