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.

The Great Arc is a fascinating account of how an arc of longitude was measured starting from Cape Comorin at the southern tip of the Indian subcontinent northwards to Hyderabad, and continuing to Dehra Dun in the Himalayas; how this helped to deduce what sort of spheroid the Earth is, and how one of the surveyors who took part in this Great Trigonometrical Survey got to place his name just a little nearer to the stars than that of any other mapmaker. I admire the persistence of these men, their determination to keep going in spite of the difficulties of the terrain, the fevers, the tigers, and finally the cold and the violence of the wind in the Himalayas. Recommended to all lovers of maps.

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.

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.