  Longitudinal and Hall voltages are measured in a clean twinned YBCO single
crystal in the liquid and solid vortex phases. For magnetic fields tilted away
from the c-axis more than about 2 deg, a scaling law |rho_xy|=A (rho_xx)^beta
with beta approx.=1.4 is observed, which is unaffected by the vortex-lattice
melting transition. The vortex-solid Hall conductivity is non-linear and
diverges to negative values at low temperature. When the magnetic field is
aligned to the c-axis, the twin-boundary correlated disorder modifies the
scaling law, and beta approx.=2. The scaling law is unaffected by the
Bose-glass transition. We discuss the scaling behaviour in terms of the
dimension-dependent theory for percolation in metallic conductors.
