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It is clear that this definition can be used to give an exact

meaning not only to two events, but to as many events as we care

to choose, and independently of the positions of the scenes of

the events with respect to the body of reference[7] (here the

railway embankment). We are thus led also to a definition of

"time" in physics. For this purpose we suppose that clocks of

identical construction are placed at the points A, B and C of the

railway line (co-ordinate system) and that they are set in such a

manner that the positions of their pointers are simultaneously

(in the above sense) the same. Under these conditions we

understand by the "time" of an event the reading (position of the

hands) of that one of these clocks which is in the immediate

vicinity (in space) of the event. In this manner a time-value is

associated with every event which is essentially capable of

observation.