Reports detailed measurements of flux flow velocity-performed by direct observation with the magneto-optical technique-and electrical resistance in high purity polycrystalline rectangular lead and indium plates subjected to a transverse magnetic field H_a. The measurements illustrated flux flow resistance in the intermediate state and tested the basic flux flow concept governed by the following relations between the average electric field in the superconductor E, the velocity of the magnetic structure v, and the driving current density j: v=(c/x_nH_c)E, E=x_nρj, where x_n is the normal phase concentration and ρ the electrical resistivity of the normal metal