Descriptions of nineteenth-century map-makers hauling their instruments up peaks of unknown altitude proved excellent value. Pelted by hailstones, their tents ablaze from the lightning and their trail obliterated by blizzards, the men of the Survey would dig in and wait. Survival depended on merino drawers, Harris tweeds and alpaca overcoats. Their boots were leather, and they ate mostly rice. They might be marooned for weeks. Then, without warning, in the chill first light of a day when the cloud had unaccountably overslept in the valleys, their patience would at last be rewarded. Sailing a sea of cumulus beneath an azure sky, a line of glistening summits would loom remotely from the ether.
With luck, from two or more of these summits tell-tale pinpricks of light would advertise the presence of other survey teams. If the theodolite was up and ready, sightings would be taken, bearings recorded and signals exchanged. The job was done. A speedy retreat down to the fleshpots of basecamp followed. Then it was on and up to the next peak.
Or so it seemed; but taking such bearings enabled the surveyors to plot the positions and heights of the distant peaks only if the location of their own peak was already known. Otherwise it was like seeking directions from a street map without first having identified your whereabouts. Fixing the positions of the other peaks depended on knowing that of the one from which one observed; its global location in terms of the world’s grid of longitude and latitude had to have been established, and so did its height above sea-level.
Obviously this information could have been obtained from prior observations taken at other vantage points in the rear. And those vantage points could in turn have been similarly established from somewhere in the foothills. But the Himalayas were hundreds of miles from any observatory capable of supplying a fix from astronomy; and they were even further from the sea, in terms of whose mean-level heights were expressed. Working back, then, somewhere there had to have been a starting point, a benchmark series of locations whose co-ordinates and heights had been deduced with a superior precision and were known with unimpeachable certainty.
I asked around, I dug out books, and the trail led back to the Great Arc – or, to give it its full title, ‘the Great Indian Arc of the Meridian’. I had never heard of it; but the Arc was indeed that benchmark series of locations. It was like the trunk of a tree, the spinal column of a skeleton. It ran for 1600 miles up the length of the subcontinent; and on the inch-perfect accuracy of its plotted locations all other surveys and locations depended.
Clearly, too, the Great Arc was something rather special. The mathematical equations involved in its computation seemed to fill enough volumes to line a library, while the instruments used to gather the raw data were man-size contraptions of cast iron and well-buffed brass which were still lovingly displayed in the Survey of India’s offices.
I ferreted further and I read on. Evidently the Great Arc was way ahead of its time. No scientific undertaking on such a massive scale had previously been attempted. Outside the regulated confines of Bourbon France and Georgian Britain, it was also the most minutely accurate land measurement on record. The accuracy was all-important because the Arc had as much to do with physics as with surveying. It was not simply an attempt to measure a subcontinent but also, incredibly, to measure and compute the precise curvature of the globe.
More prosaically, it was conceived by an elusive genius called William Lambton and was inspired by the first British conquests in the extreme south of India. The year was 1800. In North America Meriwether Lewis and William Clark had yet to set out on their epic journey across the continent. Australia was barely a penal colony; Napoleon still held Egypt; and most of the rest of Africa remained shrouded in that mysterious ‘darkness’ which was simply Europe’s ignorance.
Only in Asia, and especially India, was an embryonic imperialism detectable. Already the infant was outgrowing the womb of trade, stretching and kicking prodigiously, and taking its first unsteady strides towards dominion. Just so the Great Arc. Mirroring the progress of empire, it would forge tentatively and then inexorably inland. During forty years of high-risk travel, ingenious improvisation and awesome dedication it would come to embrace the entire length of India. And when Lambton, its endearing founder, died in central India, it would be carried to its grand Himalayan finale by the bewhiskered and cantankerous martinet who was Colonel George Everest.
At the time the scientific world was frankly amazed. The Arc was hailed as ‘one of the most stupendous works in the whole history of science’. It was ‘as near perfect a thing of its kind as has ever been undertaken’. Lambton and Everest ‘had done more for the advancement of general science than … any other body of military men’. Their celebrity was assured. Lambton was internationally fêted. George Everest was knighted by Queen Victoria; and in his honour that peak, whose discovery and measurement the Arc had made possible, was duly named.
Yet today they are utterly forgotten. Lambton is not even among the fifteen thousand worthies included in Chambers’ Biographical Dictionary. Everest is just a mountain. The progress of nineteenth-century invention was such that their science was almost instantly superseded. It now features only in histories of cartography, in academic critiques of imperialism, and in the dusty records of the Indian Survey. The Great Arc, like the great auk, has been consigned to oblivion.
Which is a pity, for it deserves better. At a time when to foreigners India was more a concept than a country, a place of uncertain extent and only fanciful maps, the Great Arc and the surveys based on it were indeed tools of imperial dominion as well as scientific enterprises. But thanks to that voluminous documentation and to George Everest’s published memoirs, the story of the Great Arc transcends both its science and its politics. Uniquely for an official scientific venture, we can savour the setbacks, share the excitement, discern the personalities. In writing this book the challenge has not been that of embroidering bare facts with vivid shades of plausible detail but of stitching into the riot of authentic adventure a thread of scientific and political plausibility. Given half a chance, jungle mishaps would have put paid to the science, personal vendettas would have obliterated the politics, and the tigers would have made off with the narrative.
If the impression given is less that of a scientific set-piece and more of a monumental example of human endeavour, then so it was. Travelling India with an eye on the Arc, I found it impossible not to become obsessed by the sheer audacity of the enterprise. Like Mount Everest, which seen from afar looks a respectable peak but not obviously the world’s highest, so the Arc viewed from a distance of two hundred years looks impressive but slightly quixotic. Get up close, though, breathe the sharp air and sense the monstrous presumption, and the Arc like the mountain soars imperiously to dwarf all else. Measuring the one, like climbing the other, is revealed as the ultimate challenge of its age.
The word ‘jungle’ comes from India. In its Hindi form of jangal, it denotes any area of uncultivated land. Indian jungles are not necessarily forested, and today less so than ever. But well away from centres of population there do still survive a few extensive and well-wooded jungle tracts, especially in eastern and central India. Often they are classed as game sanctuaries, a designation which implies few facilities for the visitor but some much-advertised protection for the wildlife.
Here tigers and elephants yet roam, hornbills flap about in the canopy like clumsy pterodactyls, and hump-backed boar rootle aggressively through the leaf mould. In the dry season a safari might seem an attractive prospect. But be warned: ‘dry’ is high-baked. Like splintering glass, dead leaves explode underfoot to alert the animals. The tracks of crumbled dirt are hard to follow, spiked with ferocious thorns, and spanned by man-size webs patrolled by bird-size spiders.
The wet season is worse still. Then, the vegetation erupts. The tracks become impassable, and the air fills with insects. Only fugitives take to the jungle in the monsoon. Fugitives and, in days gone by when maps were rare, surveyors. In the year 1819, in just such a tract between the Godavari and Kistna rivers in what is now the south-eastern state of Andhra Pradesh, an English Lieutenant, lately attached to the Great Trigonometrical