Relativity, the Special and the General Theory: A Popular Exposition by Albert Einstein

acceleration according æther behaviour body of reference Cartesian co-ordinates chest classical mechanics co-ordinate system concept of space consideration considered corresponding definition disc distance earth electrodynamics electromagnetic embankment energy equations Euclidean geometry existence experience expression fact finite fixed stars four-dimensional continuum fundamental Galileian system generalisation gravitational field H. A. Lorentz hold hypothesis idea imagine independent inertial mass inertial system infinite laws of nature light in vacuo little rods Lorentz transformation magnitude manner marble slab material points matter means measured mollusc natural laws Newton's objects observer obtained physicists plane position possible postulate of relativity principle of relativity propagation of light radius railway carriage ray of light regard result Riemann condition rigid body rotation satisfy Section simultaneous space co-ordinates special theory spectral lines spherical straight line surface system of co-ordinates theoretical theory of relativity thought three-dimensional tion tional field transmission of light universe validity velocity of light x-axis