\begin{table}%t3
%\centering
\par
\addtocounter{table}{2}
\caption {Power law indices of the mass spectrum of the clumps,  d$N/{\rm d}M \propto M^{-\alpha}$, for different mass ranges. The
mass of the clumps has been derived either from the dust continuum or from  gas emission. The arrows indicate the whole mass
range for which the fit to the mass spectrum has been done.\label{table_imf}}
\begin{tabular}{lccccc}
\hline\hline
&\multicolumn{5}{c}{Mass range $(M_\odot)$} \\
&\multicolumn{1}{c}{1.7--25} &
\multicolumn{1}{c}{10--35} &
\multicolumn{1}{c}{35--100} &
\multicolumn{1}{c}{100--$10^3$} &
 \multicolumn{1}{c}{$10^3$--$10^4$} 
\\
\hline
Dust emission \\
Tothill et~al.\ (\cite{tothill02}) &---  &1.7 &--- &--- &--- \\
Beuther \& Schilke (\cite{beuther04}) &2.5 &--- &--- &--- &--- \\
Williams et~al.\ (\cite{williams04})  & --- & \multicolumn{2}{c}{\leftarrowfill 1.14 \rightarrowfill} 
& \multicolumn{2}{c}{\leftarrowfill 2.32 \rightarrowfill} \\
This paper  & --- & \multicolumn{2}{c}{\leftarrowfill 1.5--1.9 \rightarrowfill} 
& \multicolumn{2}{c}{\leftarrowfill 2.1 \rightarrowfill} \\ 
Reid \& Wilson (\cite{reid05}) & --- & \multicolumn{2}{c}{\leftarrowfill ~0.9 \rightarrowfill} 
& \multicolumn{2}{c}{\leftarrowfill  2.0 \rightarrowfill} \\ 
\hline	   
Gas emission \\
Kramer et~al.\ (\cite{kramer98}) &--- &1.6--1.7 &1.6--1.8 &1.7--1.8 &1.7--1.8 \\
\hline 
\end{tabular}
\end{table}