\begin{table}%T6
\par
\caption{\label{abco1}Nebular elemental abundances, in units where $\log N({\rm H})=12.0$.}
%\centerline
{
\begin{tabular}{ccccccccc}
\hline
\hline
Element& ICF(CELs) &ICF(ORLs) & CELs &ORLs &Henry(1990)  & AK$^{{a}}$ (1987) &Galactic PNe & Solar\\
\hline
He & -- &1.00 &--   &11.08   &11.07   & 11.10  & 11.06   & 10.93\\
C  &1.07 &1.07 & 7.94&8.74      &  --    & --    & 8.74    &  8.52\\
N  & 14.7&1.07& 8.59&9.09      &8.34   &8.60   & 8.35    &  7.92\\
O  & 1.00&1.06  &8.56&9.08       &8.81   &8.74  & 8.68    &  8.83\\
Ne & 1.07&-- & 8.16&--       &8.19   &8.15  & 8.09    &  8.08\\
S  & 1.74&-- & 7.07&--        & --   &7.11   & 6.92    &  7.33\\
Cl & 1.00&-- & 5.05&--        &--    & --    & --      & 5.50 \\
Ar & 1.07&-- & 6.36&--        & --   &6.81   & 6.39    &  6.40\\
\hline
\end{tabular}}
\smallskip
$^{{a}}$  Aller \& Keyes (\cite{aller}).
\end{table}