## Geometrie und ErfahrungThis concise volume contains two addresses by Dr. Einstein outlining aspects of the theories. "Ether and Relativity" (1920), delivered at the University of Leyden, discusses the properties demanded of the ether of space by the theory of relativity. "Geometry and Experience" (1921), given at the Prussian Academy of Sciences, describes the limits within which the Euclidean or any other practical geometric system can be held to be approximately true in connection with the concept of a finite universe. |

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User Review - ojodelince - LibraryThingThis little book, Sidelights on Relativity, presents two lectures given by Einstein. The first, concerns the relation between the ether concept and general relativity. Einstein concludes that the ... Read full review

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absolute space according action Albert Einstein axiomatic geometry axioms bound clocks concepts deﬁnitions disc-shadows distance dualism electromagnetic ﬁeld empty space equations ether hypothesis existence ﬁnally ﬁnite universe ﬁrst ﬂuid fundamental globe gravitational ether gravitational ﬁeld H. A. Lorentz Hertz idea imagine laws of disposition lines of force logical Lorentzian ether Mach's mathematics Max Born Maxwell mean density measuring-rods mechanical interpretation medium metry motion move nature Newton's law Newtonian theory order of magnitude paper discs physicists Poincaré ponderable masses ponderable matter possible practical geometry practically-rigid bodies principles properties QUANTUM question real things relations of real Riemann's rigid bodies rigid ﬁgures seems sense of Euclidean shadow solid bodies space is inﬁnite space-time spaces of cosmic spatially ﬁnite special theory spheres spherical geometry spherical surface stars STATISTICAL THERMODYNAMICs straight line theoretical physics theory of gravitation theory of relativity THERMODYNAMICs tion tract undulatory universal space universe is spatially velocities