Begun in 1800, the measurement of The Great Indian Meridian was the longest measurement of the earth’s surface ever to have been attempted. Its 1,600 miles of inch-perfect survey took nearly fifty years, cost more lives than most contemporary wars, and involved equations more complex than any in the pre-computer age.
Rightly hailed as “one of the most stupendous works in the history of science, ” it was also one of the most perilous. 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. William Lambton, an impossible martinet, completed it. Both found the technical difficulties horrendous. With instruments weighing a half-ton, their observations often had to be conducted from flimsy platforms ninety feet above the ground or form mountain peaks enveloped in blizzard. Malaria wiped out whole survey parties; tigers and scorpions also took their toll. Yet the results were commensurate. The Great Arc made possible the mapping of the entire Indian sub-continent.