THE NEW CONCEPTION OF GRAVITATION
Geometry and reality—Euclid’s geometry and others—Contingency of Poincaré’s criterion—The real universe is not Euclidean but Riemannian—The avatars of the number π—The point of view of the drunken man—Straight and geodetic lines—The new law of universal attraction—Explanation of the anomaly of the planet Mercury—Einstein’s theory of gravitation pp. 124-147
Einstein and the Universe: a Popular Exposition of the Famous Theory · The Wunder Library — complete classics, free to read, with narration.