\begin{table} 
\par
\caption{Weighted mean linear polarization parameters of
HD~31648 (continued).} \label{t2-1}
%\centering
\par
\begin{tabular}{ccccccc}
\hline\hline
\noalign{\smallskip}
Date/& $N$ & Band & $P$ & $\sigma_{\rm p}$& $\theta$\degr & $\sigma_{\theta}\degr$\\
JD~2~400~000+  &  &    & \%   &   \%       &                &                  \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
22.10.98  & 16  &  $ U$  & 0.231 & 0.031 &47.4& 6.1 \\
51~109.57  &     &   $B$  & 0.405 & 0.021 &48.3& 2.7 \\
          &     &   $V$  & 0.381 & 0.027 &54.6& 1.8 \\
          &     &   $R$  & 0.458 & 0.020 &51.6& 1.9 \\
          &     &   $I$  & 0.440 & 0.027 &49.4& 3.2 \\
\hline
24.10.98  & 18  &   $U$  & 0.237 & 0.028 &49.3& 2.1 \\
51~111.52  &     &   $B$  & 0.414 & 0.020 &52.4& 1.7 \\
          &     &   $V$  & 0.382 & 0.025 &52.7& 2.0 \\
          &     &   $R$  & 0.418 & 0.018 &53.6& 1.8 \\
          &     &   $I$  & 0.416 & 0.025 &56.3& 2.2 \\
\hline
28.10.98  & 12  &   $U$  & 0.289 & 0.026 &50.2& 4.9 \\
51~115.59  &     &   $B$  & 0.347 & 0.017 &54.4& 2.9 \\
          &     &   $V$  & 0.282 & 0.023 &54.6& 2.8 \\
          &     &   $R$  & 0.312 & 0.016 &55.6& 2.9 \\
          &     &   $I$  & 0.420 & 0.023 &51.2& 3.2 \\
\hline
\end{tabular}
\end{table}