In this paper we produce a table of critical values of Mood's test statistic which may be used in the distribution-free comparison of the dispersions of two independent samples. As far as we know the main drawback in using this test statistic, developed more than 14 years ago, lies in the fact that its distribution has never been tabulated except for a few isolated cases. We also discuss a normal distribution approximation which may be used when the sample sizes fall outside the scope of our present table. A uniform correction for continuity cannot be suggested since Mood's statistic does not take on equi-spaced values. However, we do attempt such a correction. Our investigations indicate that this suggestion may not be worthwhile, especially for sample sizes the sum of which exceed about 30.