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However, we obtain a new result of fundamental importance when we

carry out the analogous consideration for a ray of light. With

respect to the Galileian reference-body K, such a ray of light is

transmitted rectilinearly with the velocity c. It can easily be

shown that the path of the same ray of light is no longer a

straight line when we consider it with reference to the

accelerated chest (reference-body K′). From this we conclude,

_that, in general, rays of light are propagated curvilinearly in

gravitational fields._ In two respects this result is of great

importance.