\begin{table}%t4
%\centering
\par
\caption{Observed line fluxes ($W=\int T_{\rm MB}~ {\rm d}V$ in K~km~s$^{-1}$), line 
widths ($\Delta V$ in km~s$^{-1}$) and opacities for the CN $3$ $7\over 2$--$2$ 
$ 5\over 2$ transitions. The frequencies are given in GHz. Upper limits are 
at $3\sigma$ in line flux. Numbers in brackets are uncertainties in units of the 
the last decimal place. The hyperfine line widths were taken to be fixed with an estimated error of $\lesssim$30\%.}
\label{tobs2}
\small
\begin{tabular}{lrcrrcrrcr} \hline\hline
Source & 340.265 & & & 340.261 & & & 340.247 & & \\
 & $W$ & $\Delta V$ & $\tau$ & $W$ & $\Delta V$ & $\tau$ & $W$ & $\Delta V$ & $\tau$ \\ \hline
AFGL 2591 & 1.59(14) & 2.6 & 0.06(1) & 1.36(14) & 2.7 & 0.05(1) & 19.21(15) & 3.3 & 0.55(1) \\
W3 IRS 5 & 1.66(33) & 2.6 & 0.06(1) & 1.48(13) & 2.5 & 0.06(1) & 20.68(37) & 3.8 & 0.51(1) \\
IRAS 16293 & $<$0.06 & ... & ... & 0.08(2) & 0.8 & 0.02(1) & 2.01(11) & 1.3 & 0.26(2) \\
N1333-I2  & 0.10(5) & 0.9 & 0.01($<$1) & 0.11(5) & 0.7 & 0.02(1) & 1.29(5) & 1.2 & 0.10(1) \\
N1333-I4A & $<$0.09 & ... & ... & $<$0.09 & ... & ... & 1.01(6) & 1.2 & ... \\
L1448-C   & $<$0.06 & ... & ... & 0.09(7) & 1.1 & 0.01($<$1) & 1.28(7) & 1.4 & 0.12(2) \\
L483      & 0.24(3) & 1.1 & 0.02(1) & 0.15(2) & 1.1 & 0.01($<$1) & 2.78(3) & 1.7 & 0.15(9) \\
L723      & $<$0.06 & ... & ... & $<$0.06 & ... & ... & 1.03(3) & 1.7 & ... \\
SMM4      & 0.23(4) & 2.2 & 0.01($<$1) & 0.22(4) & 2.2 & 0.01($<$1) & 2.86(4) & 2.8 & 0.10(2) \\
V1057 Cyg & $<$0.07 & ... & ... & $<$0.07 & ... & ... & 0.85(3) & 1.4 & ... \\
L1489     & $<$0.07 & ... & ... & $<$0.07 & ... & ... & 0.72(5) & 3.6 & ... \\ \hline
\end{tabular}
\end{table}