', our consideration also teaches us how the gravitational field influences the process studied.
For example, we learn that a body which is in a state of uniform rectilinear motion with respect to
(in accordance with the law of Galilei) is executing an accelerated and in general curvilinear motion with respect to the accelerated reference-body
' (chest). This acceleration or curvature corresponds to the influence on the moving body of the gravitational field prevailing relatively to
'. It is known that a gravitational field influences the movement of bodies in this way, so that our consideration supplies us with nothing essentially new.
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