\begin{table}%t6
\caption{\label{TabLinRat}Information from the same ion line flux ratios measured in the FMKs. (See text for details).}
%\centerline
 {\small \begin{tabular}{llllllllll}
\hline\hline
& & & Flux & \multicolumn{2}{c}{Single region} & \multicolumn{4}{c}{Two regions}\\
spectrum  & line $a$ & line $b$ & ratio &
           $T_{\rm e}$, K $^{*}$ & $n_{\rm e}$, cm$^{-3}$ &
                 $R_1$ & $R_2$ & $f_{{\rm PIR}, a}$ & $f_{{\rm PIR}, b}$ \\
\hline
%
{}[\ion{O}{i}]   & 63.19~$\mu$m   & 145.5~$\mu$m & $>$30 &
           $<$100              & any \\
& & & &    $200{-}1 \times 10^4$ & $>$$2\times10^5$ \\
%
{}[\ion{O}{iii}] & 51.81~$\mu$m & 88.36~$\mu$m & 2.5 &
           $300{-}1.5\times10^4$ & $500{-}1000$ &
                 1.1   & 9.7   & 0.40  &  0.85\\
{}[\ion{O}{iii}] & 88.36~$\mu$m & 5007~\AA & 0.10 &
           $1.0\times10^4$     & 800 & & & 1.0$^{*}$ & 1.0$^{*}$ \\
& & & &    $1.5\times10^4$     & 200 & & & 1.0$^{*}$ & 1.0$^{*}$ \\
{}[\ion{Ne}{iii}] & 36.01~$\mu$m & 15.56~$\mu$m & $<$$0.08$ &
           any & any \\
{}[\ion{Ne}{v}]   & 24.32~$\mu$m & 14.32~$\mu$m & $<$$0.2$  &
           $<$$3\times10^4$      & $>$$3\times10^4$ \\
%
{}[\ion{S}{iii}]  & 33.48~$\mu$m & 18.71~$\mu$m & 0.5    &
           $600{-}3\times10^4$ & $1500{-}3000$ &
           1.8 & 0.09 & 0.85 & 0.25 \\
{}[\ion{Ar}{iii}] & 21.83~$\mu$m & 8.991~$\mu$m  & $<$$0.10$ &
           any & any\\
{}[\ion{Ar}{v}]   & 7.914~$\mu$m & 13.07~$\mu$m  & $1.6$ &
           $1500{-}3 \times10^4$ & $(4{-}10)\times10^4$ &
           1.0 & 6.7 & 0.5 & 0.9\\
{}[\ion{Fe}{ii}]$^{***}$  &1.3209~$\mu$m &1.2946~$\mu$m & 0.75   &
           any  & $>$$2\times10^5$ \\
{}[\ion{Fe}{ii}]$^{***}$  &1.3209~$\mu$m & 17.94~$\mu$m & 0.024  &
           1700$-$3000$^{**}$  & any \\
 & & & &   1700$-$1800$^{**}$  & $>$$1\times10^5$$^{*}$\\
\hline
\end{tabular}}
\medskip
$^{*}$ Assumed value; $^{**}$ derived value; $^{***}$ the [\ion{Fe}{ii}] line flux ratios are discussed in Sect.~\ref{SecDiscPre}.
\end{table}