geometry package

[David Bobroff]

I'm using lilypond-book for a piece in order to be able to have better (or
at least more understandable for me) control over titles of movements and
pagebreaks.  My preamble contains:

\documentclass[a4paper]{article}
\usepackage{geometry}
\geometry{textwidth=185mm,textheight=250.000000mm,headheight=2mm,footskip=2mm}

The music looks just a bit wide on the page to my eye.  Also, the right
margin is quite narrow.  If I change textwidth to something less than 185mm
the printed area of the page shifts to the right, pushing it off the paper.
 If I set it wider it shifts to the left.  This is entirely different from
what I would expect.  What's going on?

David Bobroff