is the index of refraction of the liquid. On the other hand, owing to the smallness of
as compared with 1, we can replace (B) in the first place by
, or to the same order of approximation by
, which agrees with Fizeau's result.
XIV
THE HEURISTIC VALUE OF THE THEORY OF RELATIVITY
OUR train of thought in the foregoing pages can be epitomised in the following manner. Experience has led to the conviction that, on the one hand, the principle of relativity holds true, and that on the other hand the velocity of transmission of light in vacuo has to be considered equal to a constant
