\begin{table}%t3
\caption{Measurements of equivalent widths of four Balmer lines.}\label{tab3}
%\centering
\small
\begin{tabular}{lcccc}
\hline\hline
Cluster & H$_\alpha$      & H$_\beta$     &  H$_\gamma$     &  H$_\delta$  \\
Windows & (6540--6586) \AA & (4846--4884) \AA &  (4318--4364) \AA & (4082--4124) \AA \\
\hline
Markarian~38 & 6.5 $\pm$ 0.1 & 6.3 $\pm$ 0.1 & 6.70 $\pm$ 0.06 & 4.97 $\pm$ 0.09 \\
NGC~6604     & --2.2$\pm$ 0.1 & 2.5 $\pm$ 0.1 & 1.3 $\pm$ 0.1 & 2.2 $\pm$ 0.1 \\
Dolidze~34   & 3.6 $\pm$ 0.1 & 4.1 $\pm$ 0.1 & 4.3 $\pm$ 0.1 & 4.8 $\pm$ 0.1 \\
Berkeley~80  & 7.6 $\pm$ 0.2 & 5.0 $\pm$ 0.2 & 9.0 $\pm$  0.2 & 6.0 $\pm$ 0.3 \\
ESO~429-SC2& 4.8 $\pm$ 0.1 & 4.6 $\pm$ 0.1 & 4.1 $\pm$ 0.1 & 4.0 $\pm$ 0.1 \\
ESO~445-SC74& 4.85 $\pm$ 0.07 & 5.4 $\pm$ 0.1 & 4.3 $\pm$ 0.2 & 3.7 $\pm$ 0.2 \\
Bochum~2      & 4.4 $\pm$ 0.1 & 5.1 $\pm$ 0.1 & 5.6 $\pm$ 0.1 & 2.4 $\pm$ 0.1 \\
NGC~2311      &9.6 $\pm$ 0.1 & 13.2 $\pm$ 0.1 & 8.0 $\pm$ 0.1 & 6.3 $\pm$ 0.1 \\
NGC~2409      &5.8 $\pm$ 0.1 & 4.4 $\pm$ 0.1 & 5.1 $\pm$ 0.1 & 4.2 $\pm$ 0.1 \\
Ruprecht~2    &6.3 $\pm$ 0.1 & 6.8 $\pm$ 0.1 & 4.9 $\pm$ 0.1 & 3.34 $\pm$ 0.07 \\
Pismis~7      &6.1 $\pm$ 0.1 & 7.7 $\pm$ 0.2 & 3.7 $\pm$ 0.2 & 2.7 $\pm$ 0.1 \\
Hogg~9        &9.70 $\pm$ 0.07& 8.8 $\pm$ 0.1 & 8.62 $\pm$ 0.09 & 5.5 $\pm$ 0.1 \\
Hogg~10       &5.73 $\pm$ 0.08&5.51 $\pm$ 0.09&4.4 $\pm$ 0.1&4.29 $\pm$ 0.09\\
Basel~18      &7.83 $\pm$ 0.7&8.5 $\pm$ 0.1&7.58 $\pm$ 0.09&5.18  $\pm$  0.08\\
Trumpler~21   &6.5 $\pm$ 0.1& 6.22 $\pm$ 0.09&6.0 $\pm$ 0.1& 5.1 $\pm$ 0.1 \\
BH~151        &1.7 $\pm$ 0.1&1.2 $\pm$ 0.2&4.6 $\pm$ 0.1&3.6 $\pm$ 0.1\\
NGC~5281      &7.3 $\pm$ 0.1&6.9 $\pm$ 0.1&7.2 $\pm$ 0.1&6.5 $\pm$ 0.2\\
Lyng\aa~1     &11.5 $\pm$ 0.1&11.5 $\pm$ 0.1&7.8 $\pm$ 0.2&2.0 $\pm$ 0.1\\
Pismis~20     &2.5 $\pm$ 0.1 & 2.0 $\pm$ 0.1 & 2.0 $\pm$ 0.1 &--0.2 $\pm$ 0.1\\
Hogg~22       &4.2 $\pm$ 0.2&2.1 $\pm$ 0.1&2.9 $\pm$ 0.1&2.1 $\pm$ 0.1\\
NGC~6204      &8.88 $\pm$ 0.07&7.3 $\pm$ 0.1&7.49 $\pm$ 0.08&6.38 $\pm$ 0.09\\
Pismis~24     &4.2 $\pm$ 0.1&3.6 $\pm$ 0.1&3.5 $\pm$ 0.2&--0.2 $\pm$ 0.1\\
\hline
\end{tabular}
\end{table}