Hi, This is not about the usual gravitational lensing effect but about the speed of light in glass in Special Relativity. I have not analysed it in great detail yet, but on first inspection it seems that at least one of the following list must be true: 1) The refractive index of glass changes with relative velocity. 2) The refractive index of the glass parallel and transverse to the motion may change to different extents and possibly inversely to each other. 3) The light travelling through the the glass is "carried along" by the glass and gets a boost in the forward direction and is retarded in the backward direction. 4) The speed of light through glass probably obeys the relativistic addition of velocities law where the speed of light in the glass medium and the velocity of glass itself are added according to that equation. 5) Extending statements (4) and (5) implies that the speed of light emitted from a source embedded in a moving optical medium is not independent of the velocity of the emitter (and optical medium) relative to the observer. I was curious if anyone knows exactly which of the above statements are true and if there are already any equations published for the refractive index of a block of glass (or other light medium) that has has velocity relative to the observer?