on the Galileian transformation we should not have obtained a
contraction of the rod as a consequence of its motion.

Let us now consider a seconds-clock which is permanently situated at
the origin (x1=0) of K1. t1=0 and t1=I are two successive ticks of
this clock. The first and fourth equations of the Lorentz
transformation give for these two ticks :

t = 0

and

eq. 07: file eq07.gif

As judged from K, the clock is moving with the velocity v; as judged
from this reference-body, the time which elapses between two strokes
of the clock is not one second, but

eq. 08: file eq08.gif

seconds, i.e. a somewhat larger time. As a consequence of its motion
the clock goes more slowly than when at rest. Here also the velocity c
plays the part of an unattainable limiting velocity.



THEOREM OF THE ADDITION OF VELOCITIES.
THE EXPERIMENT OF FIZEAU