1. IOR/V/19/20 Reference (shelfmark): IOR/V/19/20 Title: Account of the Operations of the Great Trigonometrical Survey of India, Vol 19, Levelling of precision in India (1858-1909). S.G. Burrard. Dehra Dun, 1910 Collection Area: India Office Records and Private Papers Languages: English Date Range: 1910 Extent: 1 volume