deletions | additions       diff --git a/figures/Mercury/caption.tex b/figures/Mercury/caption.tex  index 0724ba5..10ecfe8 100644  --- a/figures/Mercury/caption.tex  +++ b/figures/Mercury/caption.tex 
...
\begin{centering}  \textbf{Figure 7}  \end{centering}  \par Spacings $\Delta E$ between the minima and maximum in the Franck-Hertz curve measured with a Mercury tube plotted against minimum order $n$. Although both the minima and maxima are plotted, the minimum values are really the important data points, since they correspond to the excitation energy of the atoms. Experimental results indicate a dependence on the mean free path, since the spacings between the minima appear to increase linearly. Thus the long mean free path limit (Equation 5) is likely to be a better give the best  approximation of the data. energy of the lowest excitation level.