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The Great Arc: The Dramatic Tale of How India Was Mapped and Everest Was Named

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The Great Indian Arc of the Meridian, begun in 1800, was the longest measurement of the earth's surface ever to have been attempted. Its 1,600 miles of inch-perfect survey took nearly fifty years. Hailed as one of the most stupendous works in the history of science, it was also one of the most perilous. Snowy mountains and tropical jungles, floods and fevers, tigers and scorpions all took their toll on the band of surveyors as they crossed the Indian subcontinent carrying instruments weighing half a ton.Willian Lambton, an endearing genius, had conceived the idea; George Everest, an impossible martinet, completed it. This saga of astounding adventure and gigantic personalities not only resulted in the first accurate measurement of the highest peak in the world but defined India as we know it and significant advanced our scientific understanding of the planet.

224 pages, Paperback

First published January 1, 2000

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About the author

John Keay

51 books252 followers
John Stanley Melville Keay FRGS is an English journalist and author specialising in writing popular histories about India and the Far East, often with a particular focus on their colonisation and exploration by Europeans.

John Keay is the author of about 20 books, all factual, mostly historical, and largely to do with Asia, exploration or Scotland. His first book stayed in print for thirty years; many others have become classics. His combination of meticulous research, irreverent wit, powerful narrative and lively prose have invariably been complimented by both reviewers and readers.

UK-based and a full-time author since 1973, he also wrote and presented over 100 documentaries for BBC Radios 3 and 4 from 1975-95 and guest-lectured tour groups 1990-2000. He reviews on related subjects, occasionally speaks on them, and travels extensively.

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Profile Image for Piyush Bhatia.
134 reviews260 followers
January 9, 2026
I was fascinated. An excellent chronicle.

The book gives a detailed account of the hitherto obscure project viz. The Great Trigonometrical Survey which was aimed to measure the entire Indian subcontinent with scientific precision.

The survey began with William Lambton, was continued by George Everest ( best known for having Mount Everest named in his honor), Andrew Scott, and was finally culminated by James Walker.

This survey successfully measured the height of the Himalayan giants: Everest, K2, and Kanchenjunga despite facing a number of challenges; accusations of voyeurism, and mobility, to name a few.

The Great Arc, since then, has been the backbone of the maps of India.


There's one line that describes this book more clearly :
"Where History is oblivious, Geography is tenacious."
Profile Image for Zuberino.
430 reviews81 followers
October 2, 2017


রাধানাথ শিকদারের নাম প্রথম পড়েছিলাম পিটার হপকার্কের কোন এক বইয়ে - বাঙালি, ঊনবিংশ শতকের ডাকসাঁইটে গণিতবিদ। কাশ্মীর থেকে কন্যাকুমারী পর্যন্ত ভারতবর্ষের ভৌগোলিক নাড়ি-নক্ষত্র নির্ণয়ের জন্যে সাহেবদের যে বিশাল উদ্যোগ, সেই গ্রেট ট্রিগোনোমেট্রিকাল সার্ভের শ্রেষ্ঠ "কম্পিউটার" ছিলেন তিনি, আর পৃথিবীর সবচেয়ে উঁচু পর্বতমালার উচ্চতা পরিমাপের পেছনে যে প্যাঁচালো মাপজোঁক, তার অনেকটাই বেরিয়েছিল তার হাত দিয়ে।

রাধানাথ শিকদার, গ্রেট ট্রিগ সার্ভে - এই নামগুলো মগজের কোথাও গেঁথে ছিল অনেক বছর। হঠাৎ যখন কয়েকদিন আগে পুরোনো বইয়ের দোকানে জন কী'র এই বইটি হাতে উঠে আসলো, পূর্বপরিচয়ের পুলক অনুভব করলাম। জন কী সম্পর্কে একটু সন্দেহ ছিল - তার সবচেয়ে নামী বইটি ইস্ট ইন্ডিয়া কোম্পানীর ইতিহাস, তিনি সাহেবদের সাফাই গাইবেন কিনা, লরেন্স জেমস বা নায়াল ফার্গুসনের কায়দায় ঔপনিবেশিকদের প্রশংসায় পঞ্চমুখ হবেন কিনা সে সংশয় ছিল। পড়ে বুঝলাম যে ভয় অমূলক ছিল, তেমন কোন উৎকট এজেন্ডা নিয়ে লিখতে বসেননি তিনি - মোটামুটি ভারসাম্য বজায় রেখেই বয়ান করেছেন তার ন্যারেটিভ।

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সঙ্গত কারণেই বইটি যেহেতু বিজ্ঞানের ইতিহাস - অর্থাৎ আসমুদ্রহিমাচল ভূভারতের আগপাশতলা হিসাব করার বিস্ময়কর প্রয়াসের বিবরণ - তাই এই বিজ্ঞান এবং তার পেছনে দুঃসাহসী মানুষগুলোর গল্পই প্রাধাণ্য পেয়েছে বেশী। উইলিয়াম ল্যাম্বটন এবং জর্জ ঈভরেস্ট আজ মোটামুটি বিস্মৃত। ল্যাম্বটন মরে পড়ে আছেন হিংগানঘাট নামের কোন এক অজানা গঞ্জের ততোধিক বেনামী এক কবরে, লেখক পরিশ্রম করে খুঁজে বের না করলে বোধ করি আজো কেউ জানতো না, তদুপরি কেয়ারও করতো না। অথচ কি বিস্ময়কর মানুষ। তার ধ্যানে-জ্ঞানে শুধু ছিল বিজ্ঞান - ১৯শ শতকের শুরুর দিকে যোগাযোগ ব্যবস্থা বলতে যখন ছিল শুধু হাতি ঘোড়া বা গরুর গাড়ি, মালবহনের জন্যে বোবা পশু অথবা কুলি, পাশের গ্রামের সঠিক দূরত্ব পর্যন্ত কারো জানা নেই, তখন তিনি ঠিক করেছিলেন যে ভারতবর্ষের প্রতিটি ইঞ্চির হিসেব থাকা চাই, প্রতিটি গ্রাম আর গঞ্জ, প্রতিটি নদী খাল বিল, পাহাড় পর্বত, জলা জঙ্গল আর মরুভূমির সঠিক অবস্থান এবং বিস্তার জানা জরুরী।

বহু সময় লেগেছিল, প্রায় পঞ্চাশ বছর। বহু অর্থব্যয় হয়েছে, প্রাণনাশ হয়েছে, ম্যালেরিয়া কলেরা ডিসেন্ট্রি আর বসন্তরোগে মরেছে ডজন ডজন সার্ভেয়র, বাঘে খেয়েছে বা পানিতে ডুবেছে, গ্রামের বামুন পুরোহিত থেকে শুরু করে হায়দ্রাবাদী নবাব সবার তরফ থেকে বাধা-বিপত্তি এসেছে, কেন না জাত গেল, কুল গেল, দেব-দেবী থেকে শুরু করে অন্দরমহলের মেয়েছেলেদের সম্ভ্রম সবই বুঝি গেল সাহেবদের থিওডোলাইট আর কম্পাস, লগ-চার্ট আর ক্যালকুলাসের কারণে। বইয়ের শেষে এসে লেখক দেখিয়েছেন ১৮৫৭ সালের সিপাহী বিদ্রোহের পেছনে কিঞ্চিৎ হলেও ভূমিকা রেখেছিল গ্রেট ট্রিগোনোমেট্রিকাল সার্ভে। এর প্রয়োগ তো শুধু বিশুদ্ধ বিজ্ঞানের ক্ষেত্রেই হয়নি, ভারতবর্ষের শোষণ-প্রক্রিয়া আরো মসৃণ আরো মোক্ষম করে তুলতে এমন একটা সর্বাঙ্গীণ সার্ভের আদৌ কোন বিকল্প ছিল না।

কিন্তু এর পেছনের প্রধান দুই চালিকাশক্তি, ল্যাম্বটন আর ঈভরেস্টের জীবনী অন্তত এখানে যতটুকু দেখানো হয়েছে, মনে হয়নি যে উপনিবেশিক লুটপাট বা সাহেবী বর্ণবাদ/জাত্যাভিমান এদের মূল মোটিভেশন ছিল। "ম্যাড সায়েন্টিস্ট" এর আদর্শ মডেল ছিলেন দুজনেই। রোদ-বৃষ্টি ঠান্ডা-গরম কোন কিছুতেই কোন বালাই নেই, হোক ধুধু মরু বা গহীন জঙ্গল, চোখ দুটি সর্বদাই থিওডোলাইটের কোণ-মাপকে, ম্যাপের পরবর্তী ত্রিভুজের উপরে। ডাকাতে মারলো নাকি ম্যালেরিয়া জ্বরে শরীর অর্ধেক হয়ে গেলো, তোয়াক্কা নেই, কাজটা যে শেষ করতে হবে, যেতে হবে এর পরের গ্রামে, পরের জেলায়, দ্রাঘিমাংশ আর অক্ষাংশগুলো টুকে ফেলতে হবে এক এক করে, ডিগ্রির প্রতিটি মিনিট প্রতিটি সেকেন্ড ওঠাতে হবে মানচিত্রে।

সার্ভে-বিজ্ঞানের টেকনিক্যাল খুঁটিনাটি দারুন দক্ষতায় তুলে ধরেছেন লেখক। দূরত্ব আর কোণ সঠিক মাপতে প্রয়োজন উঁচু জায়গা, পরিষ্কার আবহাওয়া। আর তাই বেশ গ্যাঞ্জাম হলেও বর্ষাকাল পছন্দ করতেন সার্ভেয়র মহোদয়গণ। বৃষ্টি -বিধৌত নির্মল বাতাসে দৃষ্টি প্রসারিত হয় অনেক দূর। যাতায়াত সমস্যা, নানা রোগবালাই সবই বর্ষাকালে প্রকট আকার ধারণ করে - কিন্তু উপায় কি? তবে ল্যাম্বটনের মৃত্যুর পরে জর্জ ঈভরেস্ট বুঝলেন শক্তিশালী ল্যাম্প জ্বালালে দিন-রাত আর ব্যাপার থাকবে না, ধীরে ধীরে শীতের অপেক্ষাকৃত অনুকূল আবহাওয়ায় সার্ভে করা সম্ভবপর হয়ে উঠলো, দুঃসহ গ্রীষ্ম-বর্ষা হয়ে গেল জিরোবার মৌসুম, পরবর্তী প্ল্যান-পরিকল্পনা করার উৎকৃষ্ট সময়।

আর উচ্চতার সন্ধান, সে তো আরেক কাহিনী - পাহাড়-টিলা, উঁচু গাছ, মন্দিরের মাথা আর মসজিদের মিনারত কিছুই বাদ যায়নি, রশি আর পুলি দিয়ে উঠে গেছে আধ-টন ওজনের থিওডোলাইট। সেই রশি ছিঁড়ে মন্দিরের চূড়া থেকে মাটিতে পড়ে ভেঙে গেছে মহা দামী যন্ত্র, ১৮০৮ সালের শুরুতে দক্ষিণ ভারতের তাঞ্জোরের রাজরাজেশ্বর মন্দিরে ঘটনাটি ঘটেছিল। তবুও সার্ভে থামেনি। বাঁশের টাওয়ার, কয়েকতলা ইটের পিলার, এইসব নির্মিত হয়েছে, এমনকি আগ্রায় সম্রাট আকবরের সমাধির মাথায় পর্যন্ত উঠে গিয়েছিল সাহেবদের মাপকযন্ত্র।

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১৯শ শতকের প্রথমার্ধে দেশটির বিবরণগুলো ভালো লেগেছে। আমাদের পূর্বপুরুষরা সাদা মানুষের এইসব কান্ড-কারখানা কি চোখে দেখেছিলেন, তার কোন লিখিত বিবরণ বা লোকস্মৃতি আছে কি না জানা নেই। এখনো সার্ভের নির্মিত কিছু উঁচু টাওয়ার পরিত্যক্ত টিকে আছে ভারতের আনাচে কানাচে। যেমন পরিত্যক্ত পড়ে ছিল জর্জ ঈভরেস্টের হিমালয় হেডকোয়ার্টার "হাতিপাও"। ঐ নীচে দেখা যায় ডেহরাডুন আর মুসুরি, আর পেছনেই একের পর এক আকাশছোঁয়া শৃঙ্গ।

কত উঁচু হবে ওগুলো? তখন পর্যন্ত বৈজ্ঞানিকরা জানতেন পৃথিবীর সবচেয়ে উঁচু পর্বতমালা দক্ষিণ আমেরিকার আন্দেজ, আর সর্বোচ্চ শিখর ছিল চিম্বোরাজো। ঈভরেস্টের নিজের তেমন কোন আগ্রহ ছিল না এই বিষয়ে, রেকর্ড-ফেকর্ড সৃষ্টি তার কাছে পোলাপান-মার্কা বাতুলতা ছিল কেবল। নেপালে তখন ব্রিটিশ রাজত্বের প্রবেশাধিকার নেই - তাই মাপজোঁক করতে হয় পাদদেশের অঞ্চল গাড়োয়াল আর কুমায়ুন থেকে। তবুও ধীরে ধীরে বোঝা গেল কি লুকিয়ে আছে উত্তরে - সাগরপৃষ্ঠ থেকে কম করে হলেও পাঁচ মাইল উঁচু তো হবেই নন্দদেবী আর কাঞ্চনজঙ্ঘা, ধবলগিরি আর অন্নপূর্ণা! আর একটি চূড়া আছে - দূরে, নেপাল তিব্বত সীমান্তে। নাম জানা নেই, সার্ভেয়রবৃন্দ নাম দিয়েছিলেন ১৫ নম্বর শৃঙ্গ (Peak XV)। ক্রমশ বোঝা গেল, এই সেই, সমগ্র পৃথিবীতে এর থেকে উঁচু স্থান আর দ্বিতীয়টি নেই।

ঈভরেস্ট তদ্দিনে অবসর নিয়ে ফেলেছেন। ত্রিশটি বছর তিনি ছিলেন সায়েব-ভারতীয় নির্বিশেষে সকলের জন্যে সাক্ষাৎ ত্রাস! বড়লাট থেকে নাদান কুলি, কাউকে ছেড়ে কথা বলতেন না, যদি তার প্রাণের সার্ভের কাজে বিন্দুমাত্র বাধা সৃষ্টি করতো কেউ। তিরিক্ষি মেজাজ, ছুরির মতো তীক্ষ্ন জিভ - তার কোমলমতি পূর্বসূরী ল্যাম্বটনের সম্পূর্ণ বিপরীত ছিলেন এসব দিক থেকে। তিন দশক ভারতবর্ষ কাঁপিয়ে, সার্ভে নামের মহাযজ্ঞ প্রায় গুটিয়ে এনে, নিজের শরীর-স্বাস্থ্য একাধিকবার ধ্বংস করে ঈভরেস্ট ফিরে গেলেন বিলেতে। অতঃপর ১৫ নম্বর শৃঙ্গের নাম তার উত্তরসূরীই ঠিক করে দিলেন - মাউন্ট এভারেস্ট - কাব্যিক ভাষায় "placed his name just a little nearer the stars than that of any other."

(রগচটা ভদ্রলোকের নাম আসলে ছিল ঈভ-রেস্ট। ওভাবেই বলতেন তিনি নিজে আর তার সমসাময়িকেরা। কিন্তু শিগগিরই সেটা ভুল উচ্চারণ করে সবাই বানিয়ে ফেললো এভারেস্ট, সেই উচ্চারণ আজ অব্দি চলে আসছে সবার মুখে। আরেকটা কথা - তিব্বতীদের দেয়া একটি নাম আছে, বহু পুরোনো চীনা ম্যাপে লিপিবদ্ধ করাও আছে সেটি, চোমোলংমা। কিন্তু এভারেস্ট নামটা বেশ দশাসই, হয়তো সে কারণেই চোমোলংমা তেমন লোকপ্রিয়তা পেলো না।)

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গ্রেট ট্রিগ সার্ভের বৈজ্ঞানিক অর্জন সেই সময়ে সারা দুনিয়ায় সমাদৃত হয়েছিল। রয়েল জিওগ্রাফিকাল সোসাইটির তৎকালীন প্রেসিডেন্ট একে বলেছিলেন "one of the most stupendous works in the whole history of science." অথচ আজ আমাদের কাছে কতটাই অজানা। জন কী-কে তাই অশেষ ধন্যবাদ, প্রায় সম্পূর্ণ বিস্মৃত অথচ ভীষণ গুরুত্বপূর্ণ এই ভারতীয় গল্পটির প্রাণবন্ত উপস্থাপনার জন্যে।
Profile Image for Lance Greenfield.
Author 42 books254 followers
June 18, 2015
As a surveyor, I was fascinated by the exploits of my forebears. It is an amazing account, and I saw many reflections of some of my own experiences. Of course, the equipment that I had access to was much more technologically based, but the principles were much the same. Also, there were a surprising number of things that have not changed over the decades.

I was in awe of these great men, and the lengths that they went to so that they could provide the baseline from which they could measure, and map, the rest of the sub-continent.

The narrative is a bit slow-going and tedious in places. Even so, I was gripped by the story, and so grateful to the author for bringing it to life for me.

This book won't interest everyone, but it is a bit of history and will interest anyone who wants to learn more about life in the 19th century, even if you don't have too much interest in the technical side of surveying.
Profile Image for Maurya.
103 reviews4 followers
May 16, 2016
A good book that loses steam in its second half. It starts off strong - describing the men, instruments of the great trigonometric survey and the perils facing them. Then it just settles into a rhythm of Everest bashing, malaria, scouting for high ground, Everest bashing, malaria...
Notably the book has exactly three lines on Radhanath Sikdar. The author believes that Sikdar's contribution to the survey has been overstated but how about introducing him first and then presenting some arguments about why he doesn't think he was relevant? And even if he was just the 'computer' for the survey who calculated the height of Mt. Everest doesn't he deserve a bit of background?
Profile Image for Maitrey.
149 reviews23 followers
July 4, 2013
The Great Arc is a wonderful little chronicle of the "Great Trigonometrical Survey" carried out in India roughly between 1800-1860 CE. Various teams surveyed India right from its southern tip, to the Himalayas.

What brings the book alive is John Keay's writing. Packed with meticulously researched details both in India and in England, Keay enriches it further with some things gained from his own recent traversing of the Great Arc.

The book is packed with memorable characters such as William Lambton, the meticulous and slightly eccentric father of the survey who also intended the Arc as a giant experiment to measure the geodesy of the globe (the "curve"), apart from mundane activities such as mapping India. Keay also recounts how he re-discovered Lambton's forgotten grave in the heart of India.

George Everest then takes over the narrative, and succeeds in connecting the Arc from Central India to the Himalayan foothills despite severe illnesses, marauding tigers and unreliable equipment. The final few chapters deal with the troublesome mapping of the Himalayas and the search for the highest mountain in the world, which was named in honour of the now retired Surveyor-General of India, Everest (which Keay says should actually be pronounced as EVE-rest, rhyming with CLEAVE-rest. Apparently, Everest himself was unhappy with the mispronounciations which dogged his life).

Overall, the book is now all the more poignant and important because the works of people such as Lambton and Everest (along with their life's work which was the Great Arc) are largely forgotten, both in India and England, which is a crying shame. During their time, they were richly feted as some of most pre-eminent men of science, and the Arc was hailed as the most scientifically exact and reliable operation undertaken anywhere in the world.

Overall the book was extremely enjoyable, mainly thanks to Keay's brilliant writing, particularly his pleasure in depicting eccentricity.
Profile Image for Kadri.
389 reviews51 followers
June 19, 2017
Just fabulous as far as a book on triangulation can be. It was interesting for me to read about the Great Indian Arc of Meridian and compare it in my mind to the Struve-Tenner Geodetic Arc (the Great Russian Arc) measured at the same time in Eastern Europe. The people who were involved in the triangulation were quite something, and obviously if you'd pair geodesy with tigers, malaria, and the highest mountains in the world, you're bound to get something interesting.
61 reviews
December 29, 2013
The Great Arc is an account of the Trigonometric Survey of India, a mammoth exercise to survey and map the Indian sub-continent from Kanyakumari (then Cape Comorin) to Kashmir and from the Indus delta to Burma, an exercise that commenced in 1802 and was completed only in 1870.
The book traces the history of the Trigonometric Survey from its conceptualisation and commencement in 1802 by its first superintendent William Lambton until the mid 1830's under his successor George Everest. In this time the primary arc tracing the 78 E longitude that passes through Delhi was surveyed in a series of interconnected triangles that stretched from Kanya Kumari in the south to Dehradun in the north.
The primary arc was to be the spine of the web of triangles that measured and surveyed the length and breadth of the country - secondary arcs branching off perpendicularly from the primary arc and these secondary arcs further lending to further arcs that then ran parallel to the primary arc, crisscrossing the length and breadth of the country.
Nothing as ambitious had been attempted before, for a survey of this magnitude in effect measured the very curvature of the earth. Mapping and measuring the heights of some of the highest peaks of the Himalayas: Nanda Devi, Kanchenjunga, Nanga Parbat, Mount Everest and others were a direct consequence of this survey.
In addition to the cartographical, geographical and wider scientific implications of the survey, the exercise had a significant political impact too. For this was a way for the East India Company that by now had clear territorial ambitions to exert its influence over the land it wished to govern. A survey of this magnitude was essential to map territories, delineate regions and divisions, build the web of infrastructure links so essential to effecting control over such a large region and above all to assert territorial superiority. Needless to add, it was a necessary aid to revenue collection, one of the primary reasons why India was attractive to the colonial ambitions of the British.
Large swathes of forest were cleared, hills flattened, monuments temples and mosques vandalized, villages razed, buildings and mansions in towns cut through... all in the name of obtaining clear lines of sight to measure the trigonometrical angles. Suffice to say the local populace and their princes were not amused. Nor did the arrogant and high handed approach of the superintendents of the Survey, George Everest included, help. Local resources were diverted, men and beasts put in the employ of the Survey and the harsh conditions of the dense jungles and working in the heat and rain claimed fatalities larger in number than wars. It would not be an exaggeration to say that this was one of the reasons contributing to the First War of Independence in 1857.
The subject matter of the book makes for interesting reading. Without complicating it with technical details, the author explains the basics of geographical survey and measurement, with its complexities and problems, in a simple enough manner. There would have been difficulties in researching a topic two centuries old, inspite of the copious amount of correspondence and publications that the mammoth effort must have generated. The book restricts itself to the first thirty or so years of the survey that took nearly seventy and traces the events during the course of its first two superintendents: William Lambton, an unassuming but much loved person with a zeal for perfection and his successor George Everest, a man with an equal zeal for perfection but loathed by his sub-ordinates for his abrasive and abusive ways. There is some reference to the administrative, logistical and practical difficulties that these men had to face, but the book is neither a humanistic account that presents the dynamics of the what-how-why nor a research treatise that delves into the technical details. It is an attempt at turning a mega event into a novel but ends up without strong characterisation with the exception of Lambton who is presented as a lovable old man and Everest as a loathable person. There is little detail on the social, political and cultural impact the survey had on the India of then. Even events that would have then been (and would now be too) sacrilegious, such as drilling a hole in the dome of a mosque, removing a pillar holding the cupola atop Akbar's tomb at Fatehpur Sikhri, mounting equipment tons heavy on the spires of temples are glossed over. Needless to add, such acts would have generated tremendous animosity and ill-will among the local population, with implications for the survey and the fledgling administration of the East India Company. An examination of these aspects would have made the book a far more absorbing read, for by the last third of the book, it gets repetitive: Everest's outbursts, the same challenges and problems in finding suitable spots for observation points etc.,
Nevertheless, the book is an interesting read on a subject matter that literally defined the world we live in. Full marks to the author for that.
Profile Image for Thom.
1,827 reviews75 followers
September 8, 2022
Interesting book about the mapping (and naming) of India by a team that included the namesake of the highest mountain on the planet.

John Keay is a really good writer, bringing in elements of history and humor. His books are informative and concise. This one slowed down a bit in the second half. I especially enjoyed the travelogue aspects as he visited a few important sites related to this work. Renovation at the Sir George Everest Heritage Park Estate continues to this date - I'd like to visit someday.

Looking forward to reading another John Keay book.
Profile Image for yórgos.
107 reviews2 followers
Read
November 17, 2018
ήβρεστ -λοιπόν - και όχι έβερεστ. όπως πρόφερε το όνομά του ο άνθρωπος που μήτε που το είδε.
Profile Image for Achyuth Sanjay.
71 reviews5 followers
June 11, 2021
Excellent book, tightly written under 150 pages making it an easy and less laborious read compared to Keay’s other tomes. This is a great book for anyone even remotely interested in geography or even British Indian history, as it’s a great window to understanding how we know what we know, and Keay’s writing is evocative enough to make you feel like you’re on an adventure spanning the length of India.
Profile Image for Brian.
387 reviews
July 5, 2019
This was a fun, non-fiction, science/history read. It’s about a bunch of people who do a north/south and east/west survey of India in the early 1800’s. Mount Everest is named after one the guys.

It’s a fascinating tale on a number of levels. First, they literally measured India...top to bottom, right to left, with metal bars. Picture using a ruler to measure the distance between New York and Los Angeles and being off by 3 inches....that’s kind of what these guys did. Through jungles and across plains in sweltering heat.

Second, one of their prime motivations was to determine whether the earth was perfectly round, egg shaped, or grapefruit shaped. (grapefruit is the right answer)

Third, the people involved were real British characters and the science involved in obtaining their required precision is pretty interesting. For instance, they measured things multiple times in multiple ways to verify their accuracy...and if they couldn’t get a measurement to work out, despite multiple meticulous tries, they generally assumed that they had stumbled upon something fundamentally new and interesting. For example, to make some of their measurements, they need some instruments to be perfectly vertical. To determine vertical, they use a weight on a string. Well, that relies on gravity and it turns out gravity varies. They found that their weighted strings were sometimes off a tiny bit depending on what the earth was like beneath them.

Finally, the people involved and their efforts were largely forgotten within a few years of completion.

This is a chapter of history that definitely could be told in a mind numbingly boring fashion, but this author made it an easy read.

Oh, and we’re all mis-pronouncing it: it’s pronounced EVE-rest...
Profile Image for Ensiform.
1,525 reviews148 followers
June 23, 2024
A thin but inspiring history: how William Lambton, George Everest (pronounced EVE-rest), and other hardy and dedicated souls mapped a great deal of India. The Arc was a series of triangles plotted through vertical and horizontal triangulation, sometimes confirmed by fixing one’s place by observation of the stars. This mapping required braving malaria- and dysentery-infested forests and plains; crunching the numbers in impossibly complex equations; lugging a vast instrument called The Great Theodolite over rugged terrain; constructing towers and scaffolding for flagmen and flares, and huge amounts of patience.

The story is awe-inspiring, if only for the bravery of these pioneers, who often faced greater casualty rates than soldiers in the name of science; but I was most impressed by the precision of the survey under the given conditions. Every variable was predicted and dealt with, even to attaching thermometers to the measuring-chains so as to calculate the metal's expansion and compensate in the resulting calculation. In all this plotting, the measuring of mountains was incidental, but Keay also reveals how the bad-tempered Everest somehow got his name attached to the world's highest peak. This book is a fine work of scholarship and very pleasant to read. However, it is a pity that there is so little on the reactions of Indians to the survey: I'd like to know how Everest's own native contingent felt, what local villagers thought on seeing the great procession, what the survey's own Indian mathematical genius felt about the project. Perhaps there is no record of their feelings, but that's a shame. Otherwise, this is a stirring tale of human achievement.
Profile Image for dejah_thoris.
1,355 reviews23 followers
March 31, 2017
A great short read about one of the most challenging cartographic projects ever attempted by the British Empire. I learned a great deal about triangulation and dedication though Mount Everest really should be named after William Lambton whose dedication to the Great Arc was surpassed only by its achievement. The only downside to this book is that it is written from the Imperialistic perspective, possibly due to the source documents. Although it was British policy retain local names for geographic features whenever possible, there is an equal amount of griping about local chiefs who protest surveyors overlooking their property and/or their women. Everest is also openly racist, advancing assistants he hires after Lambton dies over Lambton's well-trained mixed-race assistants who had been working for Lambton longer than Everest had. If you can tolerate Everest's personality, the story is fascinating, but it would have been good to include a more balanced perspective regarding the individual Indian kingdoms.
Profile Image for Arjun.
616 reviews32 followers
April 29, 2023
It's like a thrilling adventure story, but instead of Indiana Jones, it's a bunch of British guys in India measuring the distance between two points with a big stick.

Keay does an excellent job of bringing history to life, and I found myself completely engrossed in the story. The way he weaves together the science, politics, and personalities involved in this project is truly impressive.

I was blown away by the dedication and perseverance of the surveyors who worked on this project for over a decade.

At times, Keay's writing can be a bit dense and academic, which may turn off some readers. But honestly, I was so invested in the story that I didn't really mind.

I highly recommend "The Great Arc" to anyone interested in history, geography, or just a good British administrative adventure story.
Profile Image for Sneha Divakaran.
152 reviews52 followers
July 13, 2018
Well researched, superbly written.

The mapping of India is brought out to be what it was - brutal to the people in the line of sight, grand for the British, magnificent, terrible, all at the same time. Despite it being a work of history, the "character development" of the protagonists, Lambton, Everest (pronounced Eve-Rest), and India (her anger in the form of burned down survey towers, disease, and her submission in terms of the number of people she lost to this endeavor), is done very well.

Would have appreciated more maps though. Not all of us are expert surveyors or geographers.

A good read! And timely, too, for me.
Profile Image for Sreedharan.
51 reviews3 followers
May 12, 2022
While I felt most of Keay describing white people measuring distances across India as too mathematical, there are some fascinating anecdotes. It's also genuinely mindboggling how Chennai to Bangalore to Hyderabad to Nagpur to Kolkata to Dehradun and back across the Himalayas was mapped this well in the 19th century. If one ignores the math, the Great Arc is an enjoyable read.

How a racist (even by colonial standards) officer who hadn't evened seen the Himalayas until before his death is remembered for the largest mountain in the world is disappointing and remarkable at the same time.
Profile Image for Manish.
954 reviews54 followers
June 12, 2011
The story of how India was mapped, through a series of triangles, by using the basic fundamentals of trigonometry, under the leadership of William Lambton and his successor after whom the tallest peak in the world was named - George Everest. Somehow, my respect for topo sheets just went up a few notches after reading this book!
Profile Image for Jaidev.
30 reviews15 followers
April 7, 2024
This book invokes two very different reactions in me. The primary reaction is jubilant, almost romantic. The second is gloomy. Imagine you’re watching Oppenheimer: spirits rising until the point the bombs actually drop, after which you feel guilty about having felt good in the first place.

The Great Trigonometric Survey was completed over the duration of a better part of a century, across three generations of mathematicians, physicists and surveyors (they were called compasswallahs - I finally see where Rohit Gupta gets his pseudonym), and at the cost of thousands of lives. They managed to complete an accurate-to-the-inch survey of much of the subcontinent. The Great Trigonometric Survey afforded to the Raj a much welcome administrative and military efficiency over the whole subcontinent. It is perhaps only a coincidence that the events of 1857 happened only a few years after the conclusion of the survey. But it’s very likely that the Survey was among the many things that irritated Indians. And the results of the Survey certainly played no small part in quelling of the Rebellion.

After all, the survey divided the whole country into a grid of triangles. The line-of-sight needed to establish the vertices of a triangle led the surveyors to cut through jungles, mountains, rivers, settlements and even temples and mosques alike in the pursuit of accuracy. There was an oversimplifying, reductive flavour to the activities of the Survey, which might have been insulting to locals. The author duly acknowledges this, too.

But the stated goal of the Survey was deceptively innocent, even admirable: they wanted to measure the shape of the earth. India was simply in the wrong place at the wrong time. It just so happened that of all the British territories in the tropics, India was the most ‘vertical’ and most varied in its landscape, and as such uniquely suited for an ambitious geodesic experiment.




What fascinates me most is that much of the Survey happened in my backyard. I’ve spent much of my life living along the very Arc of the Meridian which the GTS proposed to measure. I grew up in Nagpur. The father of the GTS, William Lambton, is buried in Hinganghat, which is just an hour south of Nagpur. I’ve spent much of my life in Delhi, with easy access to Dehradun, which is where the survey ended, which is home to the Survey General of India. I’ve spent a lot of time in Hyderabad and Chennai, where the Survey originated. It seems like the *goras* from 200 years ago knew my country better than I do today. And it takes a contemporary *gora* to write a good book about it. Of course, there’s nothing wrong with that. Only, I regret not being introduced to this massive part of our national and scientific history in high school.

Unfortunately, the responsibility of teaching the history of science and math falls neither on the high school math teacher nor on the history teacher. After all, it would be a travesty to have kids enjoying trigonometry *and* history.
Profile Image for Divya Pal.
601 reviews3 followers
February 16, 2020
Whereas the British can be blamed for the partition of India, it can be argued that they created the concept of India by uniting the melange of warring principalities, despots and tyrants across the length and breadth of the peninsula. They may have built railway lines, irrigation canals, roads and created administrative services for the benefit of Indians, but it was primarily for their selfish interests for effective governing of the boisterous ‘natives’ that the infrastructure was set up. To enable all this, accurate mapping of the conquered territories was mandatory. The Great Trigonometrical Survey was the basis of all subsequent mapping:
Such an all-embracing map, or atlas, was now considered high desirable. To the British, somewhat in the manner of a tomcat scent-marking its territory, the map would define the area in which they had a personal interest. They called this area ‘India’, a term then alien to the peoples of south Asia and imprecise even in the European usage, and they conceived this ‘India’ as a distinct Asian entity and hence, by the criteria of colonial expansion, as a legitimate subject of dominion. The map would substantiate this idea by demonstrating their knowledge of the spatial relationships between its component cities, strongholds and geographical features, a knowledge more intimate and accurate than had ever been displayed by the country’s inhabitants.

(The emphasis in the above text is mine.)
The reasons for the First War of Independence or the Mutiny of 1857 were many, but one of precipitating factors may have been the Great Trigonometrical Survey:
But surveyors had undoubtedly fuelled both the British sense of superiority and the Indian sense of grievance. ‘Bars’ and ‘chains’ of invisible triangulation looked and sounded a lot like political strangulation. Not unwittingly the Survey had furnished the paradigm and encouraged the mind-set of an autocratic and unresponsive imperialism. Additionally, by razing whole villages, appropriating sacred hills, exhausting local supplies, antagonizing protective husbands and facilitating the assessment of the dreaded land revenue, the surveyors had probably done as much to advertise the realities of British rule and so alienate grassroots opinion as had any branch of the administration… But to Everest and his generation devotional customs and immemorial lore were just evidence of the ‘suspicious native mind.'

The book is more of an account of the main initial surveyors viz., the pioneering polymath Lambton and the cantankerous Everest (pronounced EVE-rest). Ironical that Everest never saw the massif named after him. Mussoorie, in the Himalayan foothills was the closest he came to the highest mountain in the world.
... and from this podium in the Himalayas he would conduct the Great Arc to its climax in what he reckoned to be ‘as perfect a performance as mankind has yet seen.'
Profile Image for Christiane.
758 reviews24 followers
July 15, 2025
As the title indicates, this is an account of the work of the Trigonometrical Survey of India to establish the Great Meridional Arc from Point Comorin in the South to Dun Hill in the North (1,600 miles). This was accomplished by creating a web of triangles that covered the whole subcontinent and apart from measuring India revealed the shape of the Earth.

I'm not very mathematically or scientifically-minded. What appealed to me was to learn how incredibly difficult, dangerous, costly and time-consuming these measurements were. All those innumerable baselines, triangulations, zenith readings, astronomical observations etc. with the finely made but unwieldy instruments that were available at the time, i.e. the great theodolite that was huge, heavy and awkward to transport being the size of a small tractor and requiring a dozen men to carry it up and down hills or other elevated places. And then there were the surveying rods, levelling instruments, perambulators, observatories, compensation chains and bars etc. etc.

Trees had to be felled, villages flattened, earth moved and a million things taken into account to obtain measurements as accurate as possible : e.g. the problem with plumb lines, the bending of sight lines, the way heat and cold, wet and dry affected the calculations, etc. etc. Another problem was the placing of the surveying rods. If there were hills, so well and good, if there were temples, the tops of their roofs could be used but in the Gangetic Plain where there are no elevations to speak of, towers had to be constructed.

And these were just the technical and mathematical problems. Added to those came the Indian climate which affected even the most robust and hardy of the surveyors, some of whom didn’t even survive for more than a few months. But there was not only malaria, dysentery and heat-stroke, there were also scorpions, man-eating tigers, bandits and Indian villagers fearing for their sacred places and suspicious of the goings-on on the hills at night.

Out of all those intrepid men who risked their health and often their lives for the sake of science, two stand out : William Lambton who started the mission and George Everest who finished it. Both of them spent the best part of their lives in India (the first loving it and the second bearing it) and both were passionate about their work but that’s where the comparison ends. Lambton was a good-natured, self-effacing, uncomplaining, tolerant, cheerful and friendly man adored by the children he had with a local woman and his many half-caste assistants whereas Everest was a snob with an ego the size of the mountain named after him who despised the local assistants though he had to admit to their capabilities and efficiency. He much preferred officers and gentlemen though nobody was safe from his irascible temper and violent outbursts.

Clements Markham of the Royal Geographical Society sums the mission up as follows “The danger was greater than that encountered on a battle-field [and] the percentage of deaths larger while the sort of courage … required was of a far higher order.”


Profile Image for Donna Lee.
92 reviews1 follower
February 23, 2019
This book was very disappointing. From my reading of Into The Silence (Wade Davis), I knew the basic story of the Great Trigonometrical Survey of India begun around 1800 by William Lambton and completed by his successor George Everest, after whom the tallest mountain in the world is named. What I desired was a better understanding of how these measurements were done that enabled the teams to actually do the mapping.

I know more than enough trigonometry to understand the calculations involved in the mapping: given the three angles of a right triangle and the length of one side, the lengths of the other two sides can be calculated. But the one side that was used in these calculations was the "foot" or "base" of the triangle, and it was never explained how that could be measured over an inclined or irregular surface. Without that understanding, much of what followed made little sense.

Another example from the text: "...a far greater complication arose from the fact that the earth, as well as being uneven, is round. This means that the angles of any triangle on its horizontal but rounded surface do not, as on a level plane, add up to 180 degrees. Instead they are slightly opened by the curvature and so come to something slightly more than 180 degrees. This difference is known as the spherical excess, and it has to be deducted from the angles measured before any conclusion can be drawn from them." Great, I understand that...but not how it was done.

What is in this book though is a real look at the difficulties encountered in this survey, including simple things like the expansion of tools used for measurement in hot weather. Malaria and other tropical fevers were of constant concern, and in some survey seasons workers - counted into the three digits - died. Portions of towns that obstructed the view of the surveyors were destroyed, including homes with families still living in them. Swaths of trees were felled. Temples were "altered" as needed. The British didn't care. This book also delves into the personalities of both Lambton and Everest (spoiler alert: Everest was a real shit).

All in all, if you are looking for a book on the Great Trigonometrical Survey of India, I would suggest that you look for another one to read.
5 reviews1 follower
December 8, 2024
I thoroughly enjoyed reading The Great Arc by John Keay. The book chronicles one of the most monumental surveys ever carried out in the world, the Great Trigonometric Survey of India, which aimed to measure the meridian arc from the southernmost point of India up to the Himalayas. Keay’s narrative is rich and immersive, enabling the reader to vicariously experience the hardships and triumphs of the surveyors through his vivid and detailed descriptions of the events, landscapes, and personal dramas involved.

As the story unfolds, I couldn’t help but grow disillusioned with George Everest, the surveyor after whom Mount Everest was named. Keay contrasts Everest with his predecessor, the more modest and self-effacing William Lambton, and the difference in their personalities is striking. While Lambton was a dedicated, almost humble geodesist, deeply invested in the accuracy and integrity of his work, Everest comes across as stubborn, authoritarian, and at times, downright indifferent to the human and cultural aspects of the work. The more I read, the more I found myself sympathizing with Lambton and growing increasingly frustrated with Everest's leadership style, which, in my view, lacked the sensitivity and collaboration that Lambton embodied.

What was most heart-wrenching, however, was the realization that what began as a purely scientific and monumental project had such profound consequences. The survey was not just a technical feat but a catalyst for political upheaval. It contributed to the rising resentment among Indians against British colonial rule, culminating in the Indian Rebellion of 1857, which remains one of the most significant uprisings against the British Empire. The survey, in its cold, mathematical precision, inadvertently stoked tensions and played a role in one of history’s most tragic conflicts. This stark connection between a scientific endeavor and its unintended political consequences was both eye-opening and sobering.
Profile Image for Ahsen Parwez.
8 reviews
September 27, 2023
"The Great Arc" by Joh Keay, provides a comprehensive account of The Great Trigonometric Survey of India, which is one of the most ambitious land surveys ever undertaken.

Since gaining control of Indian territories, the British had conducted several surveys. However, most of these were regionally focused and lacked sufficient accuracy. Beginning in the 1800s, the East India Company commissioned an ambitious pan-India survey, running from Chennai to Delhi, and extending further up to the Himalayan regions. It took almost six decades for completion, and was led by noted surveyors and geographers including William Lambton and George Everest. The resulting survey provided a highly accurate map of hitherto un-explored regions, and also created a baseline against which other regions in India's east-west stretch could be measured. The survey also served a scientific endeavor, and accurately established the shape of earth's curvature over large distances.

The author weaves a gripping narrative, vividly portraying of the on-ground challenges encountered by surveyors. The survey team carried bulky equipment over long distances, through forests, wide rivers and rugged mountains. A slight imbalance could compromise the equipment accuracy, and thus render it unusable. The ever-present risk of attacks from local rulers or bandits added to the peril. The team battled malaria, dengue, cholera and a myriad other tropical diseases, claiming the lives of many surveyors.

The author has also described the various tools and techniques employed by the survey. However, this is not a technical read, and Keay has ensured that the book remains accessible to a wide audience.
Profile Image for Dave Appleby.
Author 5 books11 followers
June 27, 2022
A comprehensive and sometimes fascinating account of the project to map, by triangulations, most of British-controlled India, beginning in 1800 and ending in the early 1840s. Tigers weren't the only problem the Survey faced. Most of the surveyors suffered terribly from dysentery, malaria and a variety of jungle fevers. Triangulation requires one to see survey poles and flags from a distant theodolite so trees had to be chopped down, towers built (sometimes they piggybacked on religious monuments (such as the Jain statue shown below), to the anger of the locals; sometimes the surveyors were accused by local lords of spying on their women from the towers) and sometimes villages moved. Indian dust sometimes intervened anyway. And there are intrinsic problems with mapping which need correcting; these include: thermal expansion of the metal chains used, refraction in the air causing sight lines to curve, and plumb lines don't hang true when they are near mountains.

The first leader of this endeavour was a modest man called Lambton, who got on well with his staff and others (especially the ladies). His work was critical to the success of the mapping and he has been almost totally forgotten; the author uncovered his forgotten grave. His successor George Everest (pronounce Eve-rest) was a horrible man who took all the credit for the Surveys successes and blamed his subordinates when things went wrong; he was a dreadful man-manager and he has had the highest mountain on the world (which he never saw) named after him. Life is so unfair.
277 reviews4 followers
April 7, 2021
I usually love books about eccentric geniuses who become obsessed with some narrowly focused obscure activity, but the story needs to have something to draw me in - understanding the motivation, empathizing with foibles, anything. I had no idea why Everest was so maniacal, although for a long time I thought it was the prestige of the position. But that doesn't explain his losing his mind over a 1.6 inch discrepancy. Or devoting so many miserable years to the project. Also, every anecdote really highlighted what a rotten person he was. I was then shocked that on page 163, someone else was described as lacking Everest's charisma! What charisma?? He was a surly jerk! And finally, there were instances where an entire page or more was devoted to describing some aspect of the machinery or the calibration of the equipment, but I still had a very poor idea about what was being described. A quick sketch would have been so helpful. There was room for an artist's impression of Mount Everest, but no space to draw a picture of how compensation bars were used to cancel out the different rates of expansion?
113 reviews
August 30, 2023
A well researched tale about the Trigonometrical survey of India in the early 1800s. It follows the story of the two key protagonists largely in chronological order, sharing many of their achievements and the challenges they faced along the way.

It could have been her technical and detailed given the complicated maths, but managed to balance reasonable explanations while leaving the really geeky points for another study!

There were a large number of people introduced which made for a tricky read at times, working out who was doing what, and there were lots of parts of the story that weren’t developed in detail - the book is relatively short and the shortening of the stories meant it never got boring.

In a modern era, I would have expected the book to delve more deeply into the colonial injustices - instead it was a book written in the 1990s and whole not avoiding the issue, it wasn’t focussed on the differences/inhumanities of the approach of the colonials against the native Indian inhabitants.

I definitely learned something about history and geography that I had no awareness of!
This entire review has been hidden because of spoilers.
Profile Image for Omkar Joshi.
45 reviews
March 4, 2020
Writing a minimal technical book for readers like me who are naïve when it comes to Trigonometry, Physics and geodesy is a formidable challenge. How temperature, pressure, boiling points, observing stars and such concepts, which many of us have studied only in theory, were applied to solve practical problems are described concisely in the book. Author has made a commendable attempt to introduce the Great Trigonometrical Survey to the readers. The incessant field challenges faced by the surveyors, the forces of nature disrupting the calculations, the political and economical angles etc. are well covered in a book of around 170 pages.

The author keeps on switching between the era of Lambton and Everest, often causing confusion in the timeline for the reader. Many crucial points like Sironj, Chaur etc. are mentioned across the book but aren't pointed on the map in the beginning of the book.

While it's highly recommended book, it's good to read some blogs or articles on the Internet before commencing reading.
Profile Image for Gaurav.
70 reviews3 followers
February 17, 2020
A history of George Everest and how he contributed to the Great Arc across India. The mountain is just an endnote in his journey across India while highlighting many popular conventions of the times like British contempt for natives, tiger infested forests, prevalence of tropical diseases like Malaria, the heat in the plains of North India and the troubles in mapping a great country like India from south to north and west to east. Although nobody remebers George Everest as a geodesist but he is surely paid tributes when people think of the highest mountain in the world.
The book was a slow read for me. Took longer than usual. With enough interest, it could be finished in a week or a day. The writing of John Keay goes into technical depth which makes it hard going at some points. But the writer does well in bring various point of views into one single narrative.
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