Free The Great Arc by John Keay Page B

good for it. The badly rutted roads caused constant vibration and seldom went anywhere near the pre-selected heights. Infinitely preferable were porters, who were trained to treat their load with the care it deserved. But for half a ton of machinery that meant having at least two relays, each of twelve men, dedicated solely to this job. A military escort was also found necessary, partly to overawe hostility as in the case of the poligars, and partly to prevent the theft of instruments whose brass fittings were easily mistaken for gold. The escort comprised the Indian equivalent of a sergeant, two corporals and two dozen privates, another twenty-seven mouths to feed.
    Additionally many of these men – including, it seems, Lambton himself – might summon their families whenever the Survey made a prolonged stop, usually to measure a base-line. If one of Lambton’s two European assistants happened also to be present along with his own train of dependants, the concourse would be considerable. To men who spent most of their working lives humping loads up hills in the back of beyond, such tented gatherings in the open country were a welcome relief. They were both the social and professional climax of the surveyor’s year. Discipline could be more relaxed; base-line romances became a cliché of Survey life.
    In 1804, having carried his triangles from Madras to Bangalore, Lambton pushed on to the west, leaving themeasurement of his second base-line to his senior assistant, Lieutenant John Warren. Warren, a fellow-officer in the 33rd Foot, had transferred from Mackenzie’s topographical survey much to the latter’s regret. His easy-going charm cemented a lasting friendship with Lambton and, as another self-taught astronomer and mathematician, he enjoyed his superior’s complete confidence. Nor did he disappoint. The Bangalore base-line took forty-nine days to measure and provided triumphant vindication of Lambton’s meticulous methods. For it was found that the measurement of the base by chain along the ground differed from that calculated by the triangulation brought up from the Madras base-line, all of two hundred miles away, by just 3.7 inches in the total length of 7.19 miles. Whatever critics thought about the need for Lambton’s Survey, they could hardly be unimpressed by its extraordinary accuracy.
    Happily, troublesome poligars were not found west of Bangalore. Across the Karnataka plateau, the going was easier and admitted of the largest triangle yet measured. It is a good fifty miles from Savendroog on the outskirts of Bangalore to Mullapunnaletta, a hill just west of what Lambton calls ‘the Great Statue’ at Sravana Belgola (a prominent Jain figure, bolt upright and stark naked, which is still the world’s largest monolithic sculpture). Yet in the excellent visibility the hilltop statue and then the survey flag were clearly sighted through the theodolite’s telescope, and this line duly formed one side of a giant triangle.
    Under such conditions a trigonometrical survey could move much faster than its topographical counterpart. Mackenzie, whose relations with Lambton were more correct than warm, was urging forward the men of his Mysore Survey so as to reach the west coast first. The breadth of the peninsula was ‘much wanted’, as Mackenzie put it, and he was ‘very desirous of having this closed first by our Survey for early communication to England’. Specifically ‘it would give me great pleasureif [reaching the coast] was effected before Captain Lambton’. In fact, his surveyor who was nearest to the coast was to make a dash for it as soon as Lambton hove into sight; but ‘ do not ,’ Mackenzie underlined, ‘ mention this to anyone whatever as I confide in yourself alone. ’
    Mackenzie’s men had been in the field two years longer than Lambton’s. It seemed only right that their Mysore Survey should have the honour of crossing Mysore first and so completing the first trans-peninsular