The transport properties of unexcited and excited electro-rheological (ER) fluid in combined Couette and Poiseuille flow are investigated. In particular the question of whether the fluid can be considered as a continuum with Bingham plastic constitutive properties, even though it is a two-phase solid-liquid mixture, is addressed. The hydrodynamic pressures generated using ER fluid in a Rayleigh step bearing at the limiting condition of zero net flow rate were measured. The properties exhibited by the fluid are compared with independently obtained data showing the continuum principle to be applicable to the flows examined.