Inside a tabular or array environment the \footnote
command does not work; there is a footnote mark in the table cell but
the footnote text does not appear. The solution is to use a
minipage environment as here (see minipage).
\begin{center}
\begin{minipage}{\textwidth} \centering
\begin{tabular}{l|l}
\textsc{Ship} &\textsc{Book} \\ \hline
\textit{HMS Sophie} &Master and Commander \\
\textit{HMS Polychrest} &Post Captain \\
\textit{HMS Lively} &Post Captain \\
\textit{HMS Surprise} &A number of books\footnote{%
Starting with \textit{HMS Surprise}.}
\end{tabular}
\end{minipage}
\end{center}
Inside a minipage, footnote marks are lowercase letters. Change
that with something like
\renewcommand{\thempfootnote}{\arabic{mpfootnote}}
(see \alph \Alph \arabic \roman \Roman \fnsymbol: Printing counters).
The footnotes in the prior example appear at the bottom of the
minipage. To have them appear at the bottom of the main page, as
part of the regular footnote sequence, use the \footnotemark and
\footnotetext pair and make a new counter.
\newcounter{mpFootnoteValueSaver}
\begin{center}
\begin{minipage}{\textwidth}
\setcounter{mpFootnoteValueSaver}{\value{footnote}} \centering
\begin{tabular}{l|l}
\textsc{Woman} &\textsc{Relationship} \\ \hline
Mona &Attached\footnotemark \\
Diana Villiers &Eventual wife \\
Christine Hatherleigh Wood &Fiance\footnotemark
\end{tabular}
\end{minipage}% percent sign keeps footnote text close to minipage
\stepcounter{mpFootnoteValueSaver}%
\footnotetext[\value{mpFootnoteValueSaver}]{%
Little is known other than her death.}%
\stepcounter{mpFootnoteValueSaver}%
\footnotetext[\value{mpFootnoteValueSaver}]{%
Relationship is unresolved.}
\end{center}
For a floating table environment (see table), use the
tablefootnote package.
\usepackage{tablefootnote} % in preamble
...
\begin{table}
\centering
\begin{tabular}{l|l}
\textsc{Date} &\textsc{Campaign} \\ \hline
1862 &Fort Donelson \\
1863 &Vicksburg \\
1865 &Army of Northern Virginia\tablefootnote{%
Ending the war.}
\end{tabular}
\caption{Forces captured by US Grant}
\end{table}
The footnote appears at the page bottom and is numbered in sequence with other footnotes.