## Geometrical Researches on the Theory of Parallels. Translated from the Original by George Bruce Halstead.

Austin: University of Texas, 1891. First obtainable edition in English (see below) of Lobachevsky’s revolutionary work on non-Euclidean geometry, the rare offprint issue from the Bulletin of the University of Texas, Austin. “The researches that culminated in the discovery of non-Euclidean geometry arose from unsuccessful attempts to ‘prove’ the axiom..... More

Item #2861