Chennai, then Madras, 1819. Syed Mir Mohsin Husain, a jeweller from Arcot, was working in the retailer of his employer, George Gordon, when some British navy officers stopped by with a wierd instrument, asking if Mohsin might repair it. Though he had by no means seen such an instrument earlier than, he managed to restore it, a talent famous by one of these officers, Lieutenant-Colonel Valentine Blacker, “who was thoroughly impressed with Mohsin’s ‘uncommon intelligence and acuteness’”, states a brand new ebook titled India in Triangles: The unbelievable story of how India was mapped and the Himalayasmeasured by Shruthi Rao and Meera Iyer, printed by Puffin, an imprint of Penguin Random House India. From then on, Blacker typically turned to Mohsin for assist, even appointing him as an instrument maker at the Surveyor General’s workplace when he (Blacker) turned the Surveyor-General of India in 1823.
Meera loves the story of Mohsin, this small-town jeweller, who went on to turn out to be an instrument maker and performed an important position in the Great Trigonometric Survey (GTS), “the most advanced survey of its kind in the Indian subcontinent at the time-and the largest in the world,” as India in Triangles places it. “I wish more people knew about Mohsin,” says the Bengaluru-based author and researcher, the convenor of the Bengaluru Chapter of the Indian National Trust for Art and Cultural Heritage (INTACH).
Shruthi Rao
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Special Arrangement
There are different, equally compelling personalities in the ebook, which tells the story of how the Indian subcontinent was mapped. These embrace William Lambton, who kick-started the bold undertaking; his successors, George Everest, Andrew Scott Waugh and James Walker; scores of principally unnamed Indian flagmen or khalasis; and Radhanath Sikdar, the Indian mathematician and social reformer who would go on to calculate the top of Mount Everest in 1852.
However, India in Triangles can also be about mathematical ideas, devices, and the methodology used to survey this huge land with its complicated topography. Additionally, it discusses its main outcomes — together with improved maps, a deeper understanding of the Earth’s curvature, and affirmation that Mount Everest is the world’s tallest mountain — and is full of partaking workouts, trivia, anecdotes, and information. Shruthi reveals one of them: “There is no evidence that Everest ever saw the mountain named after him,” she says, stating that it was truly named by Waugh in honour of his superior. While Everest, not like his extra easy-going predecessor Lambton, seems to have been a bit of a curmudgeon, he was additionally a “pretty impressive guy. He brought in multiple innovations and made the survey faster,” says the California-based kids’s author and editor.
Meera Iyer
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Special Arrangement
The begin of a survey
The pilot for this nice survey was performed in Banaswadi, Bengaluru, in 1800, merely a yr after the defeat of Tipu Sultan in the Fourth Anglo-Mysore War. Lambton, who was half of the British regiment that fought this struggle, had proposed this survey for 2 broad causes, explains Meera. The first was that the East India Company, which was quickly buying new territories, wanted maps. “Yes, they had maps already, but these were not very accurate,” she says.
Additionally, the geographer in Lambton sought to measure the Earth’s true form, fulfilling his long-held want to contribute to the area of geodesy. “In the 1780s, they had started trigonometrical surveys in England, and Lambton was following it very closely,” says Meera. Once Tipu Sultan was defeated, they’d entry to the whole territory of Mysore as effectively, which meant that “practically all of South India is no longer enemy territory for the British so they could go almost anywhere they wanted,” she provides. “This idea, Lambton had of drawing a line across the land, could be done. So that is how everything came together.”
William Lambton
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Special Arrangement
The GTS was primarily based on the precept of triangulation, a course of that divides a form or floor into a number of triangles. “In trigonometry, when you know the measurement of one side and two angles, you can calculate the lengths of the other two sides,” says Shruthi. Using this fundamental thought, “they were able to draw imaginary triangles across the land.”
According to her, solely the first line of the triangle —the baseline —was bodily drawn and measured on the floor. “Then, from each end point of that line, they were able to sight the third point of the triangle, measure the angles and find the length of the other two sides of the triangle,” she explains, elaborating that one of these would then turn out to be the subsequent baseline, which in flip could be used to map one other triangle, and so forth. “It became a network of triangles across India, and using these triangles and paper and pencil, they were able to map the entire country.”
A long-lasting legacy
An illustration from the ebook depicting how the baseline is measured
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Special Arrangement
The precise course of was arduous, involving the bodily labour of lugging heavy tools by way of harsh, typically hostile terrain, whereas always battling the parts. “They expected it to take around five years,” says Meera, with fun. In actuality, nevertheless, it took practically 100 years, with the Great Trigonometric Survey formally kickstarting in April 1802 in Madras two years after the pilot in Bangalore. “He chose the Madras Racecourse to set up the baseline… because it was close to St Thomas Mount, which sat on the 13th parallel, the same latitude as Bangalore,” states the ebook. “Lambton was already familiar with the Bangalore region, which would be useful when he extended his triangulation from coast to coast, going from Madras to Bangalore and onwards to Mangalore along this latitude.”
There was no wanting again from there. The surveyors would spend the subsequent few many years establishing baselines and drawing triangles all throughout the nation, at the same time as the management baton was handed on from Lambton to Everest, Waugh and eventually to Walker. “We know when it started, but not when it ended,” says Meera. “Very often, it is said that it lasted 70 years, because on-ground operations were going on for that long, but you still see reports written after 70 years. Even in the early 1900s, reports were coming out about the GTS because they were still doing calculations, still correcting things.”
What is obvious, nevertheless, is the spectacular legacy that the GTS has left behind, nonetheless lingering two centuries later. For occasion, all Government-made maps of India, since the 1830s, have been primarily based on one of the outcomes of this survey, the Everest Spheroid, which “best represents what the surface of the Earth is actually like in the Indian subcontinent,” in accordance to the ebook. It can also be helpful for folks making an attempt to perceive the Earth’s tectonic shifts. “Because the GTS benchmarks and baselines were made and measured with such accuracy, they provide useful points to geologists who study earthquakes and plate tectonics,” it additional states.
Writing a ebook about the GTS
When Shruthi went on a vacation to Mussoorie in 2014, she visited George Everest’s home, positioned in Hathipaon. “I did some research and heard about the Great Trigonometric Survey for the first time,” she says. She discovered herself wanting to write about this home, which was “at that time, completely dilapidated”, and went on to publish an article about it in a nationwide media outlet. As half of her analysis, she learn The Great Arc by the British historian and journalist John Keay, a ebook about the survey, and located herself turning into more and more fascinated by the GTS. “It has been running in my head since that time, and I wanted to write it for children,” she says. When she began researching for the ebook on-line, she found that Meera’s byline recurred in lots of of the articles about the similar survey, she says. “First, I thought I would ask her for help with research; then, I ended up asking her to co-author the book with me, and she agreed,” explains Shruthi.
Rennel Grey’s map of Hindoostan earlier than the survey
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Special Arrangement
Meera, who was immediately concerned in restoring an observatory positioned at the finish of a baseline in Kannur, off the Hennur-Bagalur Road in Bengaluru, a construction that had been used to map the panorama, says that she first laid her eyes on “this really strange building” again in 2010. She started studying about the GTS “to figure out what this structure was,” she says, including that INTACH began engaged on restoring it in 2018 or 2019. And whereas, sadly, the construction was later demolished in June 2024, “that was when my interest really took off,” says Meera, who spent quite a bit of time in numerous archives researching the survey.
Since the ebook is aimed toward youthful readers, the authors made positive that it was as conversational and easy as attainable, says Shruthi. “I give a lot of context, see that it relates to real-life situations and make sure that we not only describe trigonometry and the mathematical part of it, but also offer a bird’s eye view,” she says. “We also put in activities for children to help them get a feel of things.” And it isn’t simply kids who’re shopping for the ebook; adults appear to be having fun with it too. “I think, compared to my other books for children, we are getting a lot of adult interest because very few people know about this,” says Shruthi. “But, they’re fascinated by the topic.”
India in Triangles is accessible on-line and in any respect main bookstores
