The Great Arc – The dramatic tale of how India was mapped and Everest named.(book review)

Title :- The Great Arc – The dramatic tale of how India was mapped and Everest named.

By :- John Keay

Published :-Harper Collins  (2000), Paperback (170 pages)

Outline :- The British control over India was very much in part to the British undertaking a monumental survey over India, including parts that had yet to be brought into the British sphere of influence. The survey if roads meant the first maps of India could be prepared, that was useful for trade, sending news and for military garrisons. The British survey started out with very simple survey instruments of the time, some being French. The concept of a “standard” unit of length ( a foot) had to be undertaken in all temperature conditions. Base lines took days to calibrate etc. Once the survey got under way it progressed by triangulation over large distances, with an army of math’s to determine closure & accuracy often meant resurvey. Eventually protocols and training settled down, but the heat haze meant surveying was very limited. Then they discovered surveying at night using bonfires in round buildings with a slit enabled them much faster progress. Some stories of elephants teams being swept away, and others taken by tigers. Towards the end they reached the Himalayas and through triangulation over vast differences and from different points they established the height of Mt Everest and other mountains. This survey was a significant first in cadastral corrections, and found the planet was not round but pear shaped.

A magnificent tale of persistence, accuracy, and devotion to the task