\begin{table}%t9
\caption{\label{dheh}Differences of Balmer discontinuities $\delta D = D({\rm He/H}) - D(0.1)$ at metallicity $Z = 0.02$, as a function of $T_{\rm eff}$, $\log g$ and for different He/H~abundance 
ratios. $D(0.1)$~is for the He/H~$=$ $0.1$~ratio.}
\small%\centerline
 {
\begin{tabular}{cc|ccc}
\hline\hline
    &   & He/H = 0.2 & 0.5 & 1.0 \\ 
 $T_{\rm eff}$   & $\log g$  & \multicolumn{3}{c}{$\delta D$ (dex)} \\ 
\hline
 12~500  & 3.0   & $+$0.011  & $+$0.007 & $+$0.000 \\
        & 3.5   & $-$0.005  & $-$0.006 & $-$0.014 \\
        & 4.0   & $-$0.001  & $-$0.004 & $-$0.008 \\
 15~000  & 3.0   & $+$0.000  & $-$0.014 & $-$0.020  \\
        & 3.5   & $-$0.005  & $-$0.014 & $-$0.029 \\
        & 4.0   & $-$0.005  & $-$0.014 & $-$0.029 \\
 17~000  & 3.0   & $-$0.003  & $-$0.019 & $-$0.025 \\
        & 3.5   & $-$0.005  & $-$0.016 & $-$0.032 \\
        & 4.0   & $-$0.006  & $-$0.016 & $-$0.035 \\
 19~000  & 3.0   & $-$0.003  & $-$0.020 & $-$0.026 \\
        & 3.5   & $-$0.004  & $-$0.016 & $-$0.032 \\
        & 4.0   & $-$0.006  & $-$0.017 & $-$0.035 \\
 21~000  & 3.0   & $-$0.006  & $-$0.019 & $-$0.025 \\
        & 3.5   & $-$0.004  & $-$0.014 & $-$0.029 \\
        & 4.0   & $-$0.006  & $-$0.016 & $-$0.033 \\
 23~000  & 3.0   & $-$0.006  & $-$0.017 & $-$0.022 \\
        & 3.5   & $-$0.003  & $-$0.013 & $-$0.026 \\
        & 4.0   & $-$0.005  & $-$0.015 & $-$0.029 \\
 25~000  & 3.0   & $-$0.006  & $-$0.014 & $-$0.019 \\
        & 3.5   & $-$0.003  & $-$0.011 & $-$0.023 \\
        & 4.0   & $-$0.004  & $-$0.013 & $-$0.025 \\
 27~000  & 3.0   & $-$0.004  & $-$0.010 & $-$0.016 \\
        & 3.5   & $-$0.002  & $-$0.009 & $-$0.019 \\
        & 4.0   & $-$0.003  & $-$0.011 & $-$0.021 \\
 30~000  & 3.0   & $-$0.003  & $-$0.005 & $-$0.011 \\
        & 3.5   & $-$0.002  & $-$0.007 & $-$0.013 \\
        & 4.0   & $-$0.002  & $-$0.008 & $-$0.014 \\
\hline
\end{tabular}}
\medskip
$\delta D=0$ for all He/H abundance ratios at $T_{\rm eff}=10~000$~K.
\end{table}