  In this paper we pursue a new technique to search for evidence of a finite
Universe, making use of a spherical mexican-hat wavelet decomposition of the
microwave background fluctuations. Using the information provided by the
wavelet coefficients at several scales we test whether compact orientable flat
topologies are consistent with the COBE-DMR data. We consider topological sizes
ranging from half to twice the horizon size. A scale-scale correlation test
indicates that non-trivial topologies with appropriate topological sizes are as
consistent with the COBE-DMR data as an infinite universe. Among the finite
models the data seems to prefer a Universe which is about the size of the
horizon for all but the hypertorus and the triple-twist torus. For the latter
the wavelet technique does not seem a good discriminator of scales for the
range of topological sizes considered here, while a hypertorus has a preferred
size which is 80% of the horizon. This analysis allows us to find a best fit
topological size for each model, although cosmic variance might limit our
ability to distinguish some of the topologies.
