How the British Empire Mapped the Himalayan region in the 1860's

(This article first appeared in Measurement News Issue No. 82 March 1997)

According to Peter Hopkirk in The Great Game (OUP, Oxford, 1991) "The idea of using native explorers to carry out clandestine surveys of lawless regions beyond India's frontiers had arisen as a result of the Viceroy's strict ban on British officers venturing there. Because of this the Survey of India, which had the task of providing the government with maps of the entire sub-continent and the surrounding regions, found itself greatly hampered when it came to mapping northern Afghanistan, Turkestan and Tibet. Then a young officer working for the Survey, Captain Thomas Montgomerie of the Royal Engineers, hit upon the solution. Why not, he asked his superiors, send native explorers trained in secret surveying techniques into these forbidden regions? They were far less likely to be detected than a European, however good the latter's disguise. If they were unfortunate enough to be discovered moreover, it would be less politically embarrassing to the authorities than if a British officer was caught red-handed making maps in these sensitive and dangerous parts.

"Surprisingly perhaps, in view of the British and Indian governments' determination not to become entangled in Central Asia, Montgomerie's bold plan was approved, and over the next few years a number of Indian explorers, including Nain Singh and Kishen Singh, were dispatched in great secrecy across the frontier. All of them were hillmen, carefully chosen for their exceptional intelligence and resourcefulness. The word "pundit", which suggests a man of certain learning, became the generic name by which they were referred to. Because discovery, or even suspicion, would have spelt instant death, their existence and activities had to be kept as secret as possible. Even within the Survey of India they were known merely by a number or cryptonym. They were trained personally by Montgomerie at Dehra Dun, the Survey's headquarters in the Himalayan foothills.

"Montgomerie trained his men through exhaustive practice to take a pace of known length - 33 inches in the case of Nain Singh - which would remain constant whether they walked up hill, downhill or on the level. Next he taught them ways of keeping a precise but discreet count of the number of such paces taken during a day's march. This enabled them to measure immense distances with remarkable accuracy and without rousing suspicion. Often they travelled as Buddhist pilgrims, many of whom regularly crossed the passes to visit the holy sites of the ancient Silk Road. Every Buddhist carried a rosary of 108 beads on which to count his prayers, and also a small wood and metal prayer-wheel which he spun as he walked. Both of these Montgomerie turned to his advantage. From the rosary he removed eight beads, not enough to be noticed, but leaving a mathematically convenient 100. At every hundredth pace the Pundit would automatically slip one bead. Each completed circuit of the rosary therefore represented 10,000 paces - five miles in the case of Nain Singh.

"The totals of the day's march, together with any other discreet observations, had to be logged somewhere safe from prying eyes. It was here that the prayer-wheel, with its copper cylinder, proved invaluable. For concealed in this, in place of the usual handwritten scroll of prayers, was a roll of blank paper. This served as a log-book, which could easily be got at by releasing a secret catch and removing the top of the cylinder. Some of these prayer-wheels are still preserved in the Indian State Archives. Then there was the problem of the compass, for the Pundit was required to take regular bearings as he journeyed. Montgomerie concealed this in the lid of the prayer -wheel. Thermometers, which were needed for calculating altitudes, were hidden in the tops of the pilgrims' staves. Mercury, essential for setting an artificial horizon when taking sextant readings, was hidden in sealed cowrie shells and poured into a pilgrim's begging bowl when required. Concealed pockets were added to the Pundit's clothing and false bottoms, in which the sextants could be hidden, were built into the chests which most native travellers carried. All this work was done in the Survey of India's workshops at Dehran Dun under Montgomerie's supervision.

"The Pundits were also thoroughly trained in the art of disguise and in the use of cover stories. In the lawless lands beyond the frontier their safety would depend on just how convincingly they could play the part of holy man, pilgrim or Himalayan trader. Their disguise and cover had to stand the test of months of travelling, often in the closest intimacy with genuine pilgrims and traders. Some were away for years. One became the first Asiatic to be awarded the Royal Geographical Society's gold medal, having contributed `a greater amount of positive knowledge to the map of Asia than any other individual of our time.' At least two never returned, whilst a third was sold into slavery, although he eventually escaped. In all, their clandestine journeys were to provide a wealth of geographical intelligence over twenty years which Montgomerie and his fellow cartographers at Dehra Dun used to fill in many of the no-go areas on the British maps of Central Asia."

In Trespassers on the Roof of the World, Hopkirk described some such journeys, the following of Nain Singh. He started in the company of his cousin, Mani, but they then went separate ways to reduce the chances of discovery.

"They calibrated their instruments in the small town of Bareilly, whose location was known exactly to the Survey authorities and crossed successfully into Nepal. Nain Singh managed to attach himself to a Ladakhi caravan approaching from the west and bound for Lhasa. At one stage, however, the Ladakhi traders transferred their goods to coracles and shipped these and themselves some 85 miles down the River Tsangpo [Brahmaputra] to Shigatse, Tibet's second town. But Nain Singh, of course, had to continue the journey on foot (on what pretext is not known) so that there would be no gap in the secret route survey he had been conducting ever since leaving Bareilly - without any of his fellow travellers suspecting for a moment what he was really up to with his rosary, muttered prayers and spinning prayer-wheel.

"[In January 1866] Exactly one year after leaving Dehra Dun, Nain Singh reached Lhasa having counted every single pace of the way as well as taking innumerable clandestine compass bearings and other observations. He spent three months in the Holy City and took 20 separate observations, both solar and stellar, enabling him to establish its exact latitude (the pundits were not trained in the far more difficult skills required fro calculating longitude.) Nain Singh's observations showed Lhasa at 29.39' degrees. Today's atlases put it at 29.41'. Altitude calculations showed the Tibetan capital at 11,700 feet. Today it is generally given as 12,000 feet, the discrepancy possibly due to the readings being taken as different spots.

"In April 1866 Nain Singh learned that the Ladakhi caravan he had accompanied to Lhasa was ready to return home. The 500-mile march took over two months and followed the ancient Jong-lam trade route that stretched across Tibet from east to west, the most elevated highway in the world at 15,000 feet. Once again, Nain Singh paced every step of the way and took the necessary secret observations for his route survey, finally descending into British India after an absence of one and a half years.

"Montgomerie assimilated all his mileages, bearings and altitudes and latitudes into a map. `The Pundit I think deserves all praise, his work has stood every test capitally. ` Lhasa's longitude was calculated from the route survey, to within a quarter of a degree. Nain Singh's route survey, in which he had walked 1200 miles and counted 2,500,000 individual paces had disproved the notion that existing maps of Tibet might be correct in some respects."

"Montgomerie's full official report of the clandestine trip was sent to the Royal Geographical Society, and the Pundits' secrets were revealed to all and sundry in their Journal, including bogus prayer-wheels, doctored rosaries and concealed sextants. This elementary but massive breach of security is hard to understand, as it put both the Pundits' lives and future operations [at risk] The Journal, was only distributed to fellows of the Society , although these did include Russian explorers. But as long as it continued to publish such accounts and maps, St Petersburg remained happy. The Chinese would have had every reason to intervene, but their London Legation did not know of the Journal. It would only have needed one busybody to alert them, and simple checks at Tibetan border posts would have imperilled the entire enterprise.

"Just what drove men like Nain Singh and Kishen Singh [who undertook a five-million pace journey to Chinese Turkestan lasting four and a half years] to face such hardships and extreme dangers for their imperial masters has never been satisfactorily explained. Perhaps it was the inspirational leadership of Montgomerie, who took such a pride in their individual achievements, and who looked upon them as his sons. Or possibly it was the knowledge that they belonged to an elite, for each was aware that he had been handpicked for this great task. Or maybe Montgomerie had managed to imbue them with his own patriotic determination to fill in the blanks on the Great Game map before the Russians did. Sadly, little is known of these men as individuals, for none of them left memoirs of any kind. However, it is in Kipling's masterpiece Kim, whose characters so clearly come from the shadowy world of Captain Montgomerie, that they have their just memorial."

Other journeys and other pundits' stories are recounted by Hopkirk in the book, but what I've selectively transcribed above indicates some interesting points in common with our own less heroic methods of measurement. Calibration, counters (the rosary `rotates' with roughly the same frequency as a Jones counter), a chain of continuous measurements, temperature effects on measurement, a course map and Montgomerie sahib, the big white chief, as certifier."