In the Forbidden Land An Account of A Journey into Tibet Capture by the Tibetan Lamas and Soldiers, Imprisonment, Torture and Ultimate Release brought about by Dr. Wilson and the Political Peshkar Karak Sing-Pal

Within this book, the author presents a detailed account of their expedition through Tibet, which took place in the seasons of spring, summer, and autumn in 1897. The author relies on data from the Trigonometrical Survey to determine the elevations of towering peaks in India, including Nanda Devi, along with utilizing astronomical observations to establish the precise positions of their survey’s starting and ending points at the specific locations where they entered and exited Tibet.