The Great Arc

From S. Muthiah's Madrascapes column in today's The Hindu:

I'VE JUST heard that 200 years of mapping in India, from Cape Comorin to the Himalayas, is to be celebrated in Britain from July 12 till January 7 next year as an `Indian Festival of the Great Arc.' That's a festival that started in Delhi and Dehra Dun on April 10, last year, on the day Captain William Lambton - his colonelcy still a long way in the future - began his epic work, the Great Trigonometrical Survey of India 200 years ago...

The Great Arc: The Dramatic Tale of How India Was Mapped and Everest Was Named by John Keay is a very readable account of this feat. Lambton's survey began at St. Thomas' Mount, here in Chennai. As the jacket blurb says,

... Through hill and jungle, flood and fever, an intrepid band of surveyors carried the Arc from the southern tip of the Indian subcontinent up into the frozen wastes of the Himalayas... With instruments weighing half a ton, their observations had often to be conducted from flimsy platforms ninety feet above the ground or from mountain peaks enveloped in blizzard. Malaria wiped out whole survey parties; tigers and scorpions also took their toll...