Instruments used to accomplish the monumental task of mapping India in the 19th century are displayed here, including some designed especially for the mission by its leader, George Everest. See beautiful brass transits and scopes, plus a part-iron part-brass bar, which allowed surveyors to compensate for inaccuracies in measurements caused by the expansion and contraction of their instruments in heat and cold. The museum is not officially open to the public – you'll need permission to visit.
To get permission, go to the Surveyor General’s office at the Survey of India Compound in Harthibarkala. There, you’ll have to write a brief letter explaining why you want to view the collection. Permits are given only to those with an academic or professional interest in the subject – like a geography student or a historian – but proof of your vocation or college major isn’t demanded.