  To test the cosmic spatial isotropy, we use a rotatable torsion balance
carrying a transversely spin-polarized ferrimagnetic Dy_{6}Fe_{23} mass. With a
rotation period of one hour, the period of anisotropy signal is reduced from
one sidereal day by about 24 times, and hence the 1/f noise is greatly reduced.
Our present experimental results constrain the cosmic anisotropy Hamiltonian H
= C_{1} sigma_{1} + C_{2} sigma_{2} + C_{3} sigma_{3} (sigma_{3} is in the axis
of earth rotation) to (C_{1}^{2} +C_{2}^{2})^{1/2} = (1.8 +- 5.3) X 10^{-21} eV
and | C_{3} | = (1.2 +- 3.5) X 10^{-19} eV. This improves the previous limits
on (C_{1},C_{2}) by 120 times and C_{3} by a factor of 800.
