\begin{table}%T5 \caption{\label{table5}Plasma diagnostic.} \small%\centerline { \begin{tabular}{llccccc} \hline\hline Parameter & Lines & PB8 & NGC~2867--1 & NGC~2867--2 & PB6--1 & PB6--2 \\ \hline\noalign{\smallskip} {\elecd} (cm$^{-3}$)& {\fnitroi} ($\lambda$5198)/($\lambda$5200) & \nodata & 1100~$\pm$~450 & 850~$\pm$~300 & \nodata & \nodata \\ & {\foii} ($\lambda$3726)/($\lambda$3729) & 2650~$\pm$~750 & 3050~$\pm$~800 & 2300~$\pm$~550 & 2050~$\pm$~600 & 2200~$\pm$~550 \\ & {\fsii} ($\lambda$6716)/($\lambda$6731) & 2450~$\pm$~1000 & 3550~$\pm$~1200 & 2500~$\pm$~800 & 1750~$\pm$~900 & 2450~$\pm$~850 \\ & {\fcliii} ($\lambda$5518)/($\lambda$5538) & 2400~$\pm$~1800 & 4750~$\pm$~1100 & 4750~$\pm$~1200 & \nodata & \nodata \\ & {\fariv} ($\lambda$4711)/($\lambda$4740) & $<$6850$^{c}$ & 6800:$^{c}$ & 3900~$\pm$~1000 & 1650~$\pm$~1000 & 1750~$\pm$~950 \\ & {\elecd} (average) & 2550~$\pm$~550 & 4150~$\pm$~500 & 2850~$\pm$~400 & 1900~$\pm$~450 & 2200~$\pm$~400 \\ & & & & & & \\ $T_{\rm e}$ (K)& {\fnii} ($\lambda$6548+$\lambda$6583)/($\lambda$5755) & 8900~$\pm$~500$^{a}$& 11~750~$\pm$~400 & 11~750~$\pm$~400 & 12~350~$\pm$~950 & 12~800~$\pm$~550 \\ & {\fsii} ($\lambda$6716+$\lambda$6731)/($\lambda$4069+$\lambda$4076) & \nodata & 8450:$^{d}$ & 8250:$^{d}$ & \nodata & \nodata \\ & {\foii} ($\lambda$3726+$\lambda$3729)/($\lambda$7320+$\lambda$7330) & 7050~$\pm$~400$^{b}$& \nodata & \nodata & \nodata & \nodata \\ & & & & & & \\ & {\foiii} ($\lambda$4959+$\lambda$5007)/($\lambda$4363) & 6900~$\pm$~150 & 11~850~$\pm$~300 & 11~600~$\pm$~250 & 15~750~$\pm$~600 & 15~300~$\pm$~500 \\ & {\fariii} ($\lambda$7136+$\lambda$7751)/($\lambda$5192) & \nodata & 10~800~$\pm$~550 & 11~350~$\pm$~850 & \nodata & \nodata \\ & & & & & & \\ & {\fariv} ($\lambda$4711+$\lambda$4740)/($\lambda$7170+$\lambda$7263) & \nodata & 15~400:$^{c}$ & $>$19~870: & \nodata & \nodata \\ & & & & & \\ & $T_{\rm e}$(N{\sc ii}+O{\sc iii}) & 7000~$\pm$~150 & 11~850~$\pm$~250 & 11~600~$\pm$~300 & 15~450~$\pm$~500 & 15~050~$\pm$~450 \\ & {\hei} & 6250~$\pm$~150 & 10~900~$\pm$~250 & 10~250~$\pm$~250 & 13~250~$\pm$~550 & 13~250~$\pm$~450 \\ & Balmer Decrement & 5100$^{+1300}_{-900}$ & 8950$^{+2900}_{-1900}$& 8950$^{+2900}_{-1900}$ & \nodata & \nodata \\ \noalign{\smallskip} \hline \end{tabular}} \smallskip $^{a}$ Corrected for recombination contribution to {\fnii}~$\lambda$5755 line (see text).\\ $^{b}$ Corrected for recombination contribution to {\foii}~$\lambda$$\lambda$7320+30 lines (see text).\\ $^{ c}$ {\ariv}~$\lambda$4740.17 line affected by charge transfer in the CCD.\\ $^{ d}$ {\sii}~$\lambda$$\Lambda$4068.60, 4076.35 lines corrected for the contributions of {\ciii}~$\lambda$4067.94 line and {\oii}~$\lambda$4075.86, respectively. \end{table}