\begin{table}%t6
%Table 6\\
\caption{IUE spectrum of NGC~3242.\label{tab6}}  
%\centerline
 {\begin{tabular}{llccc}
\hline
\hline
\multicolumn{1}{c}{$\lambda$} & Ion &\multicolumn{3}{c}{Intensities}\\
\cline{3-5}
\multicolumn{1}{c}{(\AA)}& & (1) & (2) &  ($I$/H$\beta$)   \\
\hline
1239 & \ion{N}{v}    &  19   & 1.32  & 7.4 \\
1335 & \ion{C}{ii}   & 16  & 1.0  &  4.76 \\
1400 & \ion{O}{iv}  &  7.8  & 4.68 & 2.19 \\
1485 & \ion{N}{iv]} &  26  & 15.6  & 6.44 \\
1548 & \ion{C}{iv}  &  110  & 66.0  & 30.8  \\
1575 & \ion{[Ne}{v]} & 12   &  7.2  &  3.36 \\
1640 & \ion{He}{ii}  & 622   & 373  & 174  \\
1663 & \ion{O}{iii]} & 45   & 27 & 12.6 \\
1750 & \ion{N}{iii]} & 15.8  &  9.48 & 4.43 \\
1909 & \ion{C}{iii]} & 675    & 405  & 189  \\
2298 &\ion{C}{iii]} & 40    &  27   & 12.6  \\
2325 & \ion{C}{ii]}  & 26.8   & 17.0 & 7.95 \\
2423 & \ion{[Ne}{iv]} & 44   & 30.1  & 14.1  \\
2512 & \ion{He}{ii}  &  17  & 8.67 & 4.05 \\
2733 & \ion{He}{ii}  & 27  &  11.4 & 5.32  \\
2837 & \ion{[Fe}{iv]}  & 45 & 22.2 & 10.4  \\
3024 & \ion{O}{iii}  &  20  & 7.8  & 3.64  \\
3048 & \ion{O}{iii}  &  50  &  19.8 & 9.24  \\
3133 & \ion{O}{iii}  & 100  &  39.0 & 18.2  \\
3103  & \ion{He}{ii}  & 38  &  13.8 &  6.44 \\
\hline 
\end{tabular}}
\par
\smallskip
(1) Measured intensity from low resolution spectra in 
units of 10$^{-13}$~erg~cm$^{-2}$~s$^{-1}$;
(2) Intensity corrected for diaphragm size and extinction in units of
10$^{-12}$~erg~cm$^{-2}$~s$^{-1}$. 
$I$/H$\beta$ is normalized to H$\beta=100$. 
\end{table}