  With an aim to study whether the close correlation between [Na/H] and [Fe/H]
recently found in A-type stars further persists in the regime of B-type stars,
the abundances of Na were determined for 30 selected sharp-lined late B-type
stars (10000K < T_eff < 14000K) from the Na I 5890/5896 doublet. These Na
abundances were then compared with the O and Fe abundances (derived from the O
I 6156-8 and Fe II 6147/6149 lines) showing anti-correlated peculiarities. It
turned out that, unlike the case of A-type stars, [Na/H] is roughly constant at
a slightly subsolar level ([Na/H] ~ -0.2 (+/-0.2)) without any significant
correlation with [Fe/H] which shows considerable dispersion ranging from ~ -0.6
to ~ +1.0. This may serve as an important observational constraint for
understanding the abundance peculiarities along with the physical mechanism of
atomic diffusion in upper main-sequence stars of late A through late B-type
including Am and HgMn stars.
