  Crutcher, Hakobian, and Troland (2009) used OH Zeeman observations of four
nearby molecular dark clouds to show that the ratio of mass to magnetic flux
was smaller in the ~0.1 pc cores than in the ~1 pc envelopes, in contradiction
to the prediction of ambipolar diffusion driven core formation. A crucial
assumption was that the magnetic field direction is nearly the same in the
envelope and core regions of each cloud. Mouschovias and Tassis (2009) have
argued that the data are not consistent with this assumption, and presented a
new analysis that changes the conclusions of the study. Here we show that the
data are in fact consistent with the nearly uniform field direction assumption;
hence, the original study is internally self-consistent and the conclusions are
valid under the assumptions that were made. We also show that the Mouschovias
and Tassis model of magnetic fields in cloud envelopes is inconsistent with
their own analysis of the data. However, the data do not rule out a more
complex field configuration that future observations may discern.
