  We have obtained two-dimensional velocity fields in the ionized gas of a set
of 8 double-barred galaxies, at high spatial and spectral resolution, using
their H$\alpha$ emission fields measured with a scanning Fabry-Perot
spectrometer. Using the technique by which phase reversals in the non-circular
motion indicate a radius of corotation, taking advantage of the high angular
and velocity resolution we have obtained the corotation radii and the pattern
speeds of both the major bar and the small central bar in each of the galaxies;
there are few such measurements in the literature. Our results show that the
inner bar rotates more rapidly than the outer bar by a factor between 3.3 and
3.6.
