  The Ly-alpha forest provides important constraints on the smoothness of the
universe on large scales. We calculate the flux distribution along
line-of-sight to quasars in a universe made of randomly distributed clumps,
each of them with a Rayleigh-L`evi fractal structure. We consider the
probability distribution function of the normalised flux in the line-of-sight
to quasars. We show that the truncated clustering hierarchy model shows far too
many voids along the line-of-sight to quasars compared with the observed flux
distribution and the distribution in a Cold Dark Matter model. This supports
the common view that on large scales the universe is homogeneous, rather than
fractal-like.
