%   I got this from the experts at SIPB
%   works in regular style, but not in two column (e.g. in twocolumn, the
%   captions are again the same size as the main body text).
%   --steve (correspondence follows)
%
%   Try using the smallcapt documentstyle that I just wrote:
%   attach jefft
%   cp /mit/jefft/Tex/smallcapt.sty .
%   Jeff Tang
%   Information Systems Computing Support Services Consultant
%   <jefft@ATHENA.MIT.EDU>
%
\long\def\@makecaption#1#2{
   \vskip 10pt
   \setbox\@tempboxa\hbox{\footnotesize #1: #2}
   \ifdim \wd\@tempboxa >\hsize   % IF longer than one line:
       {\footnotesize #1: #2\par}            %   THEN set as ordinary paragraph.
     \else                        %   ELSE  center.
       \hbox to\hsize{\hfil\box\@tempboxa\hfil}
   \fi}

