  In gravitational instability models, \lya absorption arises from a continuous
fluctuating medium, so that spectra provide a non-linear one-dimensional
``map'' of the underlying density field. We characterise this continuous
absorption using statistical measures applied to the distribution of absorbed
flux. We describe two simple members of a family of statistics which we apply
to simulated spectra in order to show their sensitivity as probes of
cosmological parameters (H$_{0}$, $\Omega$, the initial power spectrum of
matter fluctuations) and the physical state of the IGM. We make use of SPH
simulation results to test the flux statistics, as well as presenting a
preliminary application to Keck HIRES data.
