Maureen recommended some online books that detail (and I mean detail) survey efforts in India. I looked at one (approx 1840 to 1860) Among other things, there is quite a bit of biographical information about people associated with the ongoing surveying. In the front is a table of contents and an index at the rear. Although, online word search is not enabled, the index seems fairly complete. For anyone who has ancestors who might have been involved these volumes are worth investigating. The volume I perused was over 600 pages and it is quite readable. For an Aussie, Maureen deserves credit for sharing this information. Ed (Falcon)