\begin{table}%t4
   \caption{Abundance  of  iron and of  some  elements determined in the
  present  work.  The columns provide,  respectively, the atomic number,
  the  element symbol, the number of  lines analyzed, the mean abundance
  in  the atmosphere of \hd\ with  respect to solar photosphere (Grevesse
  \& Sauval \cite{Gre98}) and the abundance in the scale log~$N$(H)~$=$ 12.}\label{tab4}
%\centering
\par
 \begin{tabular}{cl r cr }
 \hline \hline
 $Z$ &  Ident.  &  $N$   &   $\Delta$log $N$  &      log $N$~~~        \\
 \hline
 26  &   Fe I   & 221  &  --2.09+0.07      &     5.41 $\pm$ 0.07  \\
     &   Fe II  & 30   &  --2.09+0.17      &     5.41 $\pm$ 0.17  \\
 63  &   Eu II  & 6    &  --1.54+0.13      &    --1.03 $\pm$ 0.13  \\
 76  &   Os I   & 4    &  --1.23+0.12      &     0.22 $\pm$ 0.12  \\
 77  &   Ir I   & 1    &                  &     0.17 $\pm$ 0.20  \\
 82  &   Pb I   & 1    &  --1.85+0.20      &     0.10 $\pm$ 0.20  \\
 90  &   Th II  & 5    &                  &    --1.18 $\pm$ 0.11  \\
 92  &   U II   & 5    &                  & $<$--2.02 $\pm$ 0.20  \\
 \hline
 \end{tabular}
  \end{table}