  In previous work the parameter of glassiness was introduced to distinguish
between a liquid and a glass, using a formal analogy with the quantum Bose
system. The glassiness is defined in such a way that it is unity in a frozen
system and less than one in a liquid. In the present letter we revise first the
results obtained for the glassiness in a hard sphere liquid as a function of
the density. Then we investigate the influence of an attractive potential by
obtaining the glassiness as a function of the density, temperature and the
attractive tail when a square well potential is added to the hard core.
