Hi all,
This was a week of arcs. I recently saw the movie 'Evan Almighty' which is all about 'The Ark' and completed reading a book titled 'The Great Arc' by John Keay and thought of sharing some of the interesting facts and findings here. Before that, a very happy Xmas & advance New Year wishes to one and all.
Many of us might have heard about the Golden Quadrilateral project. The effort to connect India's 4 metros took several years to fructify. If that was huge, imaging measuring the whole of India – not with today's satellite technologies, of course – and this is what the book is all about. The book starts with this curious question as to how Mt. Everest was named Everest (after George Everest). Did you know that Everest never saw the mountain in his life?
Yes. Here is the story: During the early 19th century, around 1819 to be precise, Lambton, Everest's predecessor started the great arc, formally known as the great trigonometrical survey of India. The objective of the project was two fold: one to measure the British India which would help in ruling the country better and other larger goal was to figure out the earth's precise shape. Because, back then, we knew that the earth wasn't a perfect sphere. But, none knew how curved or skewed it was. Was it like an egg or a grapefruit? It took nearly 50 years before these questions could be answered with accuracy.
The project used what was called triangulation method to survey the country using instrument called theodolite. It is simple trigonometry: when we know a baseline and two angles pointing to a vertex point, the other two sides can be calculated. This was easier said than done as it required the base-lines to me measured using metallic chains/ bars and the size of a triangle was restricted by visibility often required clearing of trees or even villages and installation of towers. The survey cut across India's thickest forests and the crew faced malarial threats amongst others (The mosquito menace now is no less today but, we can get medical help). Heights of mountains could be calculated using the same technique but, that wasn't the objective. Interestingly, the survey was started in Madras (Chennai) at our very own Marina beach to measure the sea-level which would act as reference. The north south line of triangles from Kanyakumari to Dehradun was called the great arc and when the survey reached the Himalayas, the heights of the stretch of mountains drew everyone's attention. It was Waugh, Everest's successor who actually measured and after years of re-calculations, announced on March 1856 that the tallest mountain was not the Andes or any other mountain in the western world but Peak XV a.k.a.
Mt. Everest
Latitude N | Longitude E | Height |
27® 59' 16.7" | 86® 58' 5.9" | 29002 Ft |
Finally, you can preview the book here: http://browseinside.harpercollins.com.au/index.aspx?isbn13=9780006531234&pg=22 and buy it here: http://www.flipkart.com/great-arc-john-keay/0006531237-4kw3fgt95d
Trivia:
- What is Devadhanga?
What is Mi-thik Dgu-thik Bya-phur Long-nga?
