\begin{table}%t11 
\par
\caption{\label{table11}Ionic abundance ratios from permitted lines in PB~6$^{a}$.}
\small%\centerline
{
\begin{tabular}{cccccc}
\hline\hline
& & \mc{2}{c}{PB~6--1} & \mc{2}{c}{PB~6--2} \\
\hline\noalign{\smallskip}
& & $I$($\lambda$)/$I$(H$\beta$) & X$^{+i}$/H$^+$  & $I$($\lambda$)/$I$(H$\beta$) & X$^{+i}$/H$^+$ \\
Mult. & $\lambda_0$ & ($\times$10$^{-2}$) & ($\times$10$^{-5}$) & ($\times$10$^{-2}$) & ($\times$10$^{-5}$) \\
\hline\noalign{\smallskip}
& & \mc{4}{c}{C$^{++}$/H$^+$} \\
\noalign{\vskip3pt} \noalign{\hrule} \noalign{\vskip3pt}
6	& 4267.26	& 0.487:		& 49:		& 1.029~$\pm$~0.309	& {\bf 105}	 \\ 
	& Adopted	& 			&{\bf 49:}	&  			& {\bf 105~$\pm$~31 }\\
\hline\noalign{\smallskip}
& & \mc{4}{c}{C$^{3+}$/H$^+$} \\
\hline\noalign{\smallskip}
1	& 4647.42	& 1.153~$\pm$~0.415	& 154      & 0.636:		     &  86:      \\ 
	& 4650.25	& 0.734:		& 163:     & 0.553:		     & 124:       \\ 
	& Sum		& 			& 154	   &			     & 100:       \\  
18	& 4186.90	& 0.807:		& 150: 	   & 0.948~$\pm$~0.303	     & 174       \\ 
	& Adopted	& 			&{\bf 154~$\pm$~55}&		     &{\bf 174~$\pm$~56} \\
\hline\noalign{\smallskip}
& & \mc{4}{c}{C$^{4+}$/H$^+$} \\
\hline\noalign{\smallskip}
8.01	& 7726.20	& 0.954~$\pm$~0.191	& 52  	    & 0.678~$\pm$~0.129	    &  37       \\
	& Adopted	& 			&{\bf 52~$\pm$~10}&  		    & {\bf 37~$\pm$~7} \\
\hline
\end{tabular}}
\smallskip
$^{a}$ Only lines with intensity uncertainties lower than 40 \% have been considered (see text).
\end{table}