\begin{table}%t5
%\centering
\par
\caption{\label{tab:abun_out}Gas column density, $N$(H$_2$) and CH$_3$OH abundance in   outflow knots as determined from $^{12}$CO $J$=3--2 and C$^{18}$O   $J=3$--2 emission.}
\center\begin{tabular}{l r r r r r r r r}
\hline\hline\noalign{\smallskip}
 & \multicolumn{4}{c}{$^{12}$CO} & \multicolumn{4}{c}{C$^{18}$O} \\
 & $\int T_{\rm MB}$ d$\varv$ & $N_{\rm CO}^{\rm of}$ &
$x$(CH$_3$OH) & $x_{\rm of}/x_{\rm env}$ & $\int T_{\rm MB}$
d$\varv$ & $N_{\rm CO}$ & $x$(CH$_3$OH) & $x_{\rm of}/x_{\rm
  env}$ \\
Source & (K~km~s$^{-1}$) & (10$^{16}$~cm$^{-2}$) &
$\times$10$^{-6}$ & & (K~km~s$^{-1}$) & (10$^{18}$ cm$^{-2}$) &
$\times$10$^{-8}$ \\
\hline
SMM1-S & 27.5 & 1.2 & 5.1  & 5000 & 3.6 & 1.1 & 5.2 & 50 \\
\mbox{SMM4-W} & 40.7 & 0.9 & 5.0  & 1000 & 4.6 & 1.4 & 3.1 &  6 \\
SMM4-S & 44.7 & 1.7 & 19.6 & 3900 & 9.8 & 2.9 & 12  & 25 \\
\hline
\end{tabular}
\end{table}