It is among the lesser known facts of the history of science that one of the major scientific projects of the Nineteenth Century took place in India.
This project was the measurement of the Great Indian Arc of the Meridian undertaken in 1802. It was the longest measurement of the Earth’s surface ever to be attempted.
It began at the turn of the Century lasted almost fifty years covered over 1600 miles cost more lives than are lost in wars and involved complex mathematical equations which would have given modern computers minor headaches.
This project was undertaken by The Survey of India and was subsequently put under the charge of a separate institution created for this purpose called the Great Trigonometric Survey of India (GTS) .
Through exceedingly rigorous triangulation in inhospitable conditions, the project not only succeeded in mapping and measuring the Great Arc, but also made possible the first comprehensible and accurate mapping of India. In the sense, this made possible, for the first time, a scientific mapping of what had been called India.
The survey also made possible the measurement of the Great Himalayas. It first claimed and then provided definitive proof that Mount Everest was indeed the highest peak in the world.
It is a measure of the rigour and precision of the work that modern day satellite images confirm, almost to the inch, the work done by the GTS between 150-200 years ago.
Though many British officers were involved in the triangulation project, it was Major William Lambton whose brainchild it actually was and who was responsible for the precision with which the work was carried out.
In spite of the fact that what he was attempting was so exacting and difficult, he insisted on precision instruments, checking and counter-checking calculation after calculation, in the midst of high fever, torrential rains, attacks by wild animals and mutinous workers. From the inception of the project in 1802 till his death in 1823, Lambton worked ceaselessly at his triangulation, for which he received recognition not only in India but from the world s scientific community.
George Everest took charge of the Great Trigonometric Survey after Lambton s death and decided that he would not only complete Lambton’s project but also extend the scope of the triangulation to 400 miles beyond Agra to include Delhi and the mountains beyond the plains.
For over two decades, Everest pursued Lambton s dream with a commitment that was remarkable. He completed the Arc in 1843 leading the President of London s Royal Geographical Society to declare that it was one of the most stupendous works in the whole history of science .
The film by Pankaj Butalia, ‘Tracing The Arc‘ deals with the period associated with both Lambton and Everest. It looks at what motivated the British to undertake such extensive mapping of India in the first place.
To what extent were these maps necessary for expansion of the empire, and to what extent were these devices with which to access remote areas of India to see what they had to offer which was of commercial benefit to the East India Company are questions the film addresses.
The film also attempts to understand the extent to which our perceptions of ourselves as Indians originates with a conception of the geographical space that links us, as well as of the manner in which it links us.
It touches upon the way in which imperialist / expansionist policies underlay the entire project – the way in which map making by the Survey of India went hand in hand with the measurement of the Great Indian Arc of the Meridian by the Great Trigonometric Survey of India. In a sense the history of Cartography was linked up to both the history of science as well as to the ideology of British India.