\begin{table}%t5
  \caption{Column densities of \ion{H}{i} measured from the \iue~spectra, when good data were available.}\label{gas-dust}
\par
\small%\centerline
 {
\begin{tabular}{llcc}
  \hline
  \hline
  Stars     & Column density                           &  $N$(H$_{\rm tot}$)/$E(B-V)$                  & $f$ \\ 
            & of \ion{H}{i} (cm$^{-2}$)                &  (atoms cm$^{-2}$ mag$^{-1}$)          &  \\
  \hline                                        
%&&&&&&& \\[-8pt]
  HD~250550 & $\rm 9.00_{-4.0}^{+5.0}$ $\times$ 10$^{20}$ (1)  & $\rm 4.26_{-1.92}^{+2.33}$ $\times$ 10$^{21}$ & $\rm 0.04_{-0.03}^{+0.06}$ \\  
  HD~259431 & $\rm 1.60_{-0.6}^{+2.4}$ $\times$ 10$^{21}$ (1)  & $\rm 9.51_{-3.49}^{+10.2}$ $\times$ 10$^{21}$ & $\rm 0.35_{-0.24}^{+0.37}$  \\    
  HD~38087  & $\rm 1.91_{-0.41}^{+2.09}$ $\times$ 10$^{21}$    & $\rm 8.46_{-1.41}^{+7.9}$ $\times$ 10$^{21}$  & $\rm 0.22_{-0.13}^{+0.15}$ \\  
  HD~76534  & $\rm 2.40_{-1.4}^{+1.6}$ $\times$ 10$^{21}$      & $\rm 1.25_{-0.63}^{+0.77}$ $\times$ 10$^{22}$ & $\rm 0.27_{-0.16}^{+0.51}$    \\
  \hline
\end{tabular}}
\medskip
 (1) \cite{JCB03}.
\end{table}