Editing Mount Everest (section)

===19th century===
[[File:MountEverestRelief.png|thumb|upright=1.5|Mount Everest [[Cartographic relief depiction|relief map]]]]
[[File:Tibetan Plateau and Mount Everest.png|thumb|Profiles of the full elevation of Mount Everest]]

In 1802, the British began the [[Great Trigonometrical Survey]] of India to fix the locations, heights, and names of the world's highest mountains. Starting in southern India, the survey teams moved northward using giant [[theodolite]]s, each weighing {{convert|500|kg|lb|abbr=on}} and requiring 12 men to carry, to measure heights as accurately as possible. They reached the Himalayan foothills by the 1830s, but [[Kingdom of Nepal|Nepal]] was unwilling to allow the British to enter the country due to suspicions of their intentions. Several requests by the surveyors to enter Nepal were denied.<ref name=everest_bwp70>{{cite book |title= Everest – The Best Writing and Pictures from Seventy Years of Human Endeavour |editor=Peter Gillman| year=1993 |publisher=Little, Brown and Company|isbn=978-0-316-90489-6 |pages=10–13}}</ref>

The British were forced to continue their observations from [[Terai]], a region south of Nepal which is parallel to the Himalayas. Conditions in Terai were difficult because of torrential rains and [[malaria]]. Three survey officers died from malaria while two others had to retire because of failing health.<ref name=everest_bwp70/>

Nonetheless, in 1847, the British continued the survey and began detailed observations of the Himalayan peaks from observation stations up to {{convert|240|km|mi|abbr=on}} distant. Weather restricted work to the last three months of the year. In November 1847, [[Andrew Scott Waugh]], the British [[Surveyor General of India]], made several observations from the Sawajpore station at the east end of the Himalayas. [[Kangchenjunga]] was then [[List of past presumed highest mountains|considered the highest peak in the world]], and with interest, he noted a peak beyond it, about {{convert|230|km|mi|abbr=on}} away. John Armstrong, one of Waugh's subordinates, also saw the peak from a site farther west and called it peak "b". Waugh would later write that the observations indicated that peak "b" was higher than Kangchenjunga, but closer observations were required for verification. The following year, Waugh sent a survey official back to Terai to make closer observations of peak "b", but clouds thwarted his attempts.<ref name=everest_bwp70/>

In 1849, Waugh dispatched James Nicolson to the area, who made two observations from Jirol, {{convert|190|km|mi|abbr=on}} away. Nicolson then took the largest [[theodolite]] and headed east, obtaining over 30 observations from five different locations, with the closest being {{convert|174|km|mi|abbr=on}} from the peak.<ref name=everest_bwp70/>

Nicolson retreated to [[Patna]] on the [[Ganges]] to perform the necessary calculations based on his observations. His raw data gave an average height of {{convert|9200|m|ft|abbr=on}} for peak "b", but this did not consider [[light refraction]], which distorts heights. However, the number clearly indicated that peak "b" was higher than Kangchenjunga. Nicolson contracted malaria and was forced to return home without finishing his calculations. Michael Hennessy, one of Waugh's assistants, had begun designating peaks based on [[Roman numerals]], with Kangchenjunga named Peak&nbsp;IX. Peak "b" now became known as Peak&nbsp;XV.<ref name=everest_bwp70/>

In 1852, stationed at the survey headquarters in [[Dehradun]], [[Radhanath Sikdar]], an Indian mathematician and surveyor from [[Bengal]] was the first to identify Everest as the world's highest peak, using [[trigonometry|trigonometric]] calculations based on Nicolson's measurements.<ref name=BBC_mwde>{{cite news|title=The man who "discovered" Everest|url=http://news.bbc.co.uk/2/hi/south_asia/3193576.stm|work=BBC News|date=20 October 2003|access-date=11 April 2008|first=Soutik|last=Biswas|archive-date=15 April 2008|archive-url=https://web.archive.org/web/20080415093207/http://news.bbc.co.uk/2/hi/south_asia/3193576.stm|url-status=live}}</ref> An official announcement that Peak&nbsp;XV was the highest was delayed for several years as the calculations were repeatedly verified. Waugh began work on Nicolson's data in 1854, and along with his staff spent almost two years working on the numbers, having to deal with the problems of light refraction, barometric pressure, and temperature over the vast distances of the observations. Finally, in March 1856 he announced his findings in a letter to his deputy in [[Kolkata|Calcutta]]. Kangchenjunga was declared to be {{convert|28156|ft|m|abbr=on|order=flip}}, while Peak&nbsp;XV was given the height of {{convert|29002|ft|m|abbr=on|order=flip}}. Waugh concluded that Peak&nbsp;XV was "most probably the highest in the world".<ref name=everest_bwp70/> Peak&nbsp;XV (measured in feet) was calculated to be exactly {{convert|29000|ft|m|abbr=on|sigfig=5|}} high, but was publicly declared to be {{convert|29002|ft|m|abbr=on|sigfig=5|}} in order to avoid the impression that an exact height of 29000&nbsp;ft was nothing more than a rounded estimate.<ref name=tas1982>{{cite journal|title=Letters to the Editor|journal=The American Statistician|volume=36|number=1|date=February 1982|pages=64–67|jstor=2684102|doi=10.1080/00031305.1982.10482782|last1=Stegman|first1=Charles E|last2=Bellhouse|first2=David|last3=Ehrenberg|first3=A.S. C|last4=Mantel|first4=Nathan|last5=Proschan|first5=Frank|last6=Gianola|first6=Daniel|last7=Searle|first7=S.R|last8=Speed|first8=F.M|last9=Milliken|first9=G.A}}</ref> Waugh is sometimes playfully credited with being "the first person to put two feet on top of Mount Everest".<ref>{{cite book|title=The Pendulum Paradigm: Variations on a Theme and the Measure of Heaven and Earth|page=267| author=Beech, Martin|year=2014| publisher=Universal-Publishers}}</ref>