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the great arc

On the face of it, surveying and map-making don’t sound like intriguing fare for a book, right? But what if the real intention of the map-makers is to determine the shape of the Earth itself? What if their efforts also have the side-effect of accurately measuring (or even “discovering”) the tallest peak on Earth? And what if one of the map-makers is called Everest? In his book The Great Arc: The Dramatic Tale of How India Was Mapped and Everest Was Named, John Keay talks about these events from about two centuries ago, and infects us with his fascination for them.

I wonder if there is something similar in the way astronomers and historians are wired. Neither are apparently interested in the here and now — the former are fascinated by objects that are at a great spatial distance, the latter by events that are at a great temporal distance. I think what ties them back to the rest of us is that their findings can sometimes shed light on who we are, and how we came to be that way. Keay’s two main protagonists are as dedicated to the cause of geodesy as today’s scientists and engineers are to, say, designing space shuttles. William Lambton and George Everest keep abreast of the latest discoveries regarding the shape of the Earth and related experiments from other parts of the planet, and are keen to feed back to the scientific community their own results. Like today’s scientists, they too need to justify their work in terms of practical usefulness (to the British, map-making was a well-understood instrument of policy; it also had usefulness for navigators) rather than as scientific research alone, and like today’s engineers they too need to favourably impress the powers that be, so that their project is supported. Cost-cutting exercises and the need to work with limited resources are also familiar themes to them.

If a lot of this sounds similar to today, some things are definitely not. Everest laughs at the natives for thinking that malarial fevers arise from witchcraft rather than natural causes, while he himself believes that they come from the air, or unwholesome soils. It would be seventy years before the anopheles mosquito would be pinned down as the cause of malaria, in the same part of the country where Everest suffered from it. Keay also argues that Lambton’s death was caused in part by medical ignorance. Some of the advice Lambton got from his doctor, and the blood-letting that was part of his treatment (as was common practice at the time) seem completely antiquated to us today. It is probably a related fact that the average life expectancy of a European man in the tropical climate of India was about 45 years, and certain regions and seasons would be especially harsh on them physically and even mentally.

Lambton’s grave is at Hinganghat in India, and in as obscure a location as certain parts of the man’s life. (Keay and his wife (re)discovered this grave, in a nice bit of historical detective work.) Having spent many years in North America, possibly through official oversight, he had a reversal of fortune, and came to India under the orders of the future Duke of Wellington, victor at Waterloo. (Other famous figures of the time, such as physicist Henry Kater, also intersect the lives of Keay’s protagonists.) Though the stories of Lambton’s life in North America are lost in time, it is clear that while there, he taught himself mathematics and other sciences, which later led to his becoming the originator of geodesic work in India. Highly regarded for his scientific abilities and integrity, and well-known for his care with the half-ton theodolite that was central to his work, Lambton was also beloved by his crew, thanks to his mild manner, simplicity and kind treatment of them.

Not so his successor Everest (pronounced Eve-rest, rather than Ever-rest). Keay describes his career as “illustrious but controversial”, and he come across as a cantankerous man, ready to criticize and not generous with giving credit. Born in Greenwich, on the prime meridian, he was keen on taking over Lambton’s job, and was ready to take desperate measures to prove his worth for it. Unlike Lambton, whose notes included no personal commentary, Everest wrote about many of the events and non-technical details that were part of his work and so we know his story far better. (It is interesting that men from a wide variety of fields wrote so extensively back then. It is a tradition worth reviving.) He also lived much longer than Lambton, and, having returned to London, became feted in his lifetime.

It was well after Everest’s main work on the meridian (the great north-south arc that formed the backbone of the survey of India) was done that the eastern end of the Himalayas was accurately mapped. It was a former assistant of Everest’s who determined the tallest peak in the Himalayas, and only after doubly and triply verifying the observations and computations was it announced as such in 1856, along with the proposal to name it after his boss. It was a somewhat controversial choice, and one of the reasons it stood was that the Indian mutiny of 1857 distracted from matters such as names of peaks.

The ironic part is that the trignonometric survey was never primarily interested in determining whether the Himalayas contained the tallest peak on the planet (rather the peaks of the Andes or Europe that had been accurately measured before), and if so which one it might be. Their focus was very much on geodesy — Everest even wanted to extend all the way into Russia the meridian that already extended to the southern tip of India. Other parties were directly interested in measuring the heights of Himalayan peaks, but to determine heights accurately one needed an inch-perfect (or at least foot-perfect) measurement of heights all the way from sea-level, and this was only possible through the meticulous and scientific methods of the survey.

The fact that Everest’s name is ‘placed a little nearer the stars’ is thus a quirk of history. He never sought that honour, but neither was he modest or humble enough to object to it. In this sense, Keay (and we) are given a hero who we never really warm to, though his scientific achievements are impressive without doubt. His predecessor, Lambton, is far more likeable, and no less impressive, yet history has placed him much lower in the fame-stakes than Everest.

As someone who mostly reads fiction, this account of history was a surpsisingly engaging read. (Thanks to the anonymous librarian who put it out on the “Staff Picks” shelf. Oh and could fiction also start having an index of terms at the end of the book?! That would be really useful.) History is perhaps better suited to story-telling than other topics of non-fiction anyway, but Keay has great facility with language and a wonderful ability to convey a lot of information compactly, mixing in just the right amount of interesting detail (“base-line romances became a cliche of Survey life”) and wit to keep the reader interested. Another thing that helps is that characters from the past easily get imbued with an air of sepia-tinted innocence and romance, at least in my eyes: we know about them, their achievements and follies, while they know nothing about us. Here too Keay plays the romance card sparsely and well. In his description of the ruins of Hathipaon (Everest’s Dehradun residence), we see his tenderness towards things of the past, but overall, rather than getting nostalgic, his focus remains firmly on the story.

I also enjoyed the scientific and engineering aspects of surveying and geodesy described in the book: the effects of the irregular shape of the Earth, observations of stars to accurately establish location, the precision and care in establishing base-lines, the problems with plumb lines, the use of and problems caused by refraction, the common practice of climbing up on temples, gopurams and other structures (even St. Paul’s in London) to get good sightlines at great distances (the lower pollution levels back then must have helped there!), the bringing down of towns or cutting off of peaks of hills to get a good sightline, the use of talented humans as “computers” to perform and update computations constantly, the back and forth between scholars regarding research results, the later use of barometers and the boiling point of water to determine altitude etc. A comment in the book that I liked especially is that when experienced observers consistently came up with the same discrepancy in their results, they were probably ‘on the verge of some important discovery’.

Science is slow and full of drudgery at times, as any scientist will attest to, especially the experimentalists. This book conveys that this fact has always been true, even in what was a century of great discoveries. But it also describes the passion of these men for their work (and they are all men), and how that work translates to something we take for granted today, such as accurate maps and topographical information. John Keay’s book is a worthy and engaging tribute to this particular chapter of history and of science.