1. IOR/V/19/10 Reference (shelfmark): IOR/V/19/10 Title: Account of the Operations of the Great Trigonometrical Survey of India, Vol 9, Electro-telegraphic longtitude operations executed during the years 1875-77 and 1880-81 by Lt Col W.M. Campbell and Major W.J. Heaviside. J.T. Walker. Dehra Dun, 1883 Collection Area: India Office Records and Private Papers Languages: English Date Range: 1883 Extent: 1 volume