1802 - William Lambton, the father of the Great Trigonometrical Survey creates the base-line measurement outside Madras.
1804 - First triangulation of The Great Arc
1808 - The half ton theodolite, used for the triangulation measurements falls and is damaged whilst being hoisted to the top of Brihadishwara temple at Tanjore.
1809 - Cape Comorin base lines completed.
1815 - The Great Arc completed to Bidar (west of Hyderabad) and the Arc, becomes ‘the longest that has ever been measurement on the surface of the globe’
1817–19 - Pindari and Third Maratha wars extend British control and increased the importance of The Great Arc survey.
1818 - Boxing Day; Lieutenant George Everest arrives in Hyderabad as Lambton’s assistant. Cost of The Great Arc running at £6,000 p.a. with no end in sight.
1819 – January; William Lambton returns to Hyderabad never to return to The Great Arc. Everest left in full control of the Arc
1819-20 - Everest struck down by Yellapuram fever in the jungles of Kistna-Godavari
1822 - Everest taken ill and spends a year convalescing at the Cape.
1823 - 19th January, William Lambton dies at Hinganghat. Everest confirmed as Superintendent of the Great Trigonometrical Survey.
1825 - Camp hit by typhoon. Great theodolite damaged.
1829 - Poor record of 15 dead in a single season.
1830 - Great Trigonometrical Survey is questioned as it is thought impossible to cross the heart of central India and vast Ganges – Jamna plain.
1831 - A successful demonstration in Calcutta to the influential of British India finds new support for The Great Arc and more importantly, new funds are granted to push The Great Arc north through central India.
1833 - The Great Arc starts again across the plains of Hindustan. George Everest, two assistants, three sub-assistants, four elephants, 42 camels, 30 horses, 700 natives make up the survey party
1834 - The Great Arc reaches Fatehpur Sikri. For the first time the position of the Taj Mahal in Agra is precisely recorded.
1835 - Four successive attacks of fever confines Everest to his bed for six months. ‘During which time I was once bled to fainting, had upwards of 1000 leeches…..’
1835-37 - Sixteen great towers from 40 to 60 feet high are completed across northern India to support the half ton theodolite.
1836 – The Great Arc now 1000 men strong.
1837 – Last step in the triangulation needed to measure the heights of the Himalaya Range.
1839 –1840 – Everest installs the ‘Astronomical Circles’ in specially built observatories at Sironj and Kaliana to establish the latitude and longitude of the Arc’s extremities.
1840–1841 – Same procedure followed at Bidar and Sironj. To the success of the Arc Everest notes ‘no two elements in nature more definitively known’
1841–1843 - Everest works on the Arc data concluding that semi–diameter of the equator at nearly 21 million feet exceeded the northern hemisphere’s diameter by exactly 67,260 feet. The compression of the poles in terms of the diameter of the equator is thus 1:311.044. Therefore the earth is shaped like a grapefruit and not a ball.
1856 – Peak XV in the Himalaya Range identified. Height above sea level 29,002.
Peak XV named Mount Everest.
1861 – George Everest knighted
