🚀 go-pugleaf

I am running LaTeX Version 2.09 <7 Dec 1989>, with TeX, C Version 3.14t3 on
a Sun SPARCstation.

I have the following LaTeX file which is a very stripped down version of a 
table, and the alignment of the columns is extremely weird - and as far as I am concerned is
wrong (well at least it is not what I'd expect!).

The file is :

\documentstyle{article}
 
\begin{document}
 
\begin{tabular}{ccc}
\multicolumn{3}{c}{this-is-a-very-long-word}\\
I   & V   & H  \\
2.2 & 1.9 & 5.2 \\
1.7 & 2.0 & 2.8 \\
\end{tabular}
 
\end{document}

Now, what I see is that the 3 output columns (I, V and H) are not spread 
evenly under the heading, but there is a lot more space between the V and H
columns than between the I and V columns.    It makes no difference if the
multicolumn above is one word or a number of words.

Does anyone have any ideas how to force equal spacing between the columns?
And can anyone tell me why it doesn't do what I expect it should??

-- 

				Stephen Meatheringham
				Mt. Stromlo Observatory
				Private Bag, Weston Creek P.O.
				ACT 2611, AUSTRALIA
				email : sjm@moggie.anu.edu.au