21. Goldingham estimated the Madras observatory at 18 17 21 E and these were used by the Trigonometrical Survey. 22. Previously to this he had made a trigonometrical survey of part of the Algarves in Portugal in 1836. 23. In the 1890s Rawnsley's Bluff was home to a trigonometrical station, supporting surveying in South Australia. 24. This was reported in'The Synoptical Volume XXXV of the Trigonometrical Survey of India'published in 1910. 25. The structure is known locally as the " Trig Tower " because trigonometrical survey readings are taken from it. 26. The title of his doctoral thesis was " Topics in the Theory of Uniqueness of Trigonometrical Series ". 27. He made extensive explorations of Gippsland, always making his land valuations after trigonometrical survey and collection of geological specimens. 28. In 1830 Bordon invented a new apparatus for accurately measuring the base line for the upcoming Massachusetts'Trigonometrical Survey. 29. It was not until 1853 That a structure was placed on the summit, a trigonometrical station, for survey purposes. 30. The Indian mathematician Radhanath Sikdar was employed as a " computer " for the Great Trigonometrical Survey of India in 1840.
