11. Goldingham estimated the Madras observatory at 18 17 21 E and these were used by the Trigonometrical Survey . 12. Previously to this he had made a trigonometrical survey of part of the Algarves in Portugal in 1836. 13. In 1830 Bordon invented a new apparatus for accurately measuring the base line for the upcoming Massachusetts'Trigonometrical Survey . 14. He made extensive explorations of Gippsland, always making his land valuations after trigonometrical survey and collection of geological specimens. 15. The structure is known locally as the " Trig Tower " because trigonometrical survey readings are taken from it. 16. A trigonometrical survey which Benedict XIV soon after had made in the papal states strikingly confirmed the French geographer's results. 17. In 1856, Godwin-Austen joined the Trigonometrical Survey of India and began to work in Kashmir under Captain Thomas George Montgomerie. 18. The Indian mathematician Radhanath Sikdar was employed as a " computer " for the Great Trigonometrical Survey of India in 1840. 19. On 1 January 1878 he was appointed Surveyor General of India, retaining the office of superintendent of the great trigonometrical survey . 20. In that year he was appointed geologist to the Trigonometrical Survey ; and in 1816-1818 he was president of the Geological Society.
