Keywords: Calcutta Baseline 1832.jpg Great Trigonometrical Survey measurement of the Calcutta baseline in 1832 by George Everest The engraving is based on a sketch by James Prinsep It shows a Ramsden chain being set on coffers supported by pickets The tent is to avoid expansion due to heat The boning telescope is used to align the links of the chain Reprint in Historical records of the survey of India Volume 4 1830-1843 by R H Phillimore 1954 1832 Sketch by James Prinsep Great Trigonometrical Survey PD-old-70-1923 |