TY - JOUR T1 - On the Degree of Uncertainty Which Local Attraction, If Not Allowed for, Occasions in the Map of a Country, and in the Mean Figure of the Earth as Determined by Geodesy: A Method of Obtaining the Mean Figure Free from Ambiguity, from a Comparison of the Anglo-Gallic, Russian, and Indian Arcs: And Speculations on the Constitution of the Earth's Crust. JF - Proceedings of the Royal Society of London (1854-1905) VL - 13 SP - 18 EP - 19 PY - 1863/01/01/ UR - http://dx.doi.org/10.1098/rspl.1863.0009 M3 - doi:10.1098/rspl.1863.0009 AU - Pratt, J. ER -