  We present final results from the WA98 experiment which provide first
measurements of Bose-Einstein correlations of direct photons in
ultrarelativistic heavy ion collisions. Invariant interferometric radii were
extracted in the range $100<K_T<300$ MeV/c and compared to interferometric
radii of charged pions. The yield of direct photons for $100<p_T<300$ MeV/c was
extracted from the correlation strength parameter and compared to the yield of
direct photons measured in WA98 at higher $p_T$ with the statistical
subtraction method, and to predictions of a fireball model.
