\begin{table}%t1
  \caption{\label{summary}Summary of $\eta$ values derived with the method of
  direct temperature estimates in the redshift range $2.58 \le z \le 2.74$.}
   $$
  \begin{array}{l c c c c}
    \hline\hline
               & \multicolumn{2}{c}{{\rm Turbulent}} & \multicolumn{2}{c}{{\rm Thermal+turbulent}}\\
              & \langle\log\eta\rangle & {\rm median} & \langle\log\eta\rangle & {\rm median}\\
                       \hline
           {\rm HE~2347-4342} & 2.00 \pm 0.63 & 1.85 & 2.21 \pm 0.82 & 1.88 \\
{\rm HS~1700+6416} & 1.97 \pm 0.58 & 1.95 & 2.11 \pm 0.32 & 2.03 \\
{\rm both~sight~lines} & 1.98 \pm 0.59 & 1.90 & 2.16 \pm 0.62 & 2.01 \\
                       \hline
         \end{array}
     $$
   \end{table}