vcenter help

[James E. Bailey]

I'm reading through 1.8.2.3, trying to understand how to center two  
lines of text. How does \vcenter work? The documentation doesn't  
really provide an example, so I'm kinda confused. I got it to work  
with \center-align, but I'm understanding because of recent discussion  
that sometime in the future \center-align won't be used for this.

\version "2.11.54"

\markup \column { \vcenter { "first line" "second line" } }

\markup \center-align {"first line" "second line" }