The equation of transfer of radiation and
the magneto-ionic theory are used to derive expressions for the degree of
polarization of thermal " solar noise " due to a general magnetic
field of the sun. In particular, the net polarization of 600 Mc/s. (50 cm.)
radiation corresponding to the maximum phase of the eclipse of November 1,
1948, as seen from Melbourne, Victoria, is evaluated theoretically and compared
with observational evidence. This leads to an upper limit of 11 gauss for the
surface field- strength at the solar poles at the time of observation.