vspace multiplier

[Andrew Bernard]

Dear List,

New to lilypond, and with a background in IT in every language _except_ 
Scheme (;-)), I wonder if somebody could explain why vspace multiplies 
its argument by 3.0?

I am also seeing no effect if I use arguments less than one. What is 
going on here, and why this behaviour?

The root question is, how can I control vertical spacing of text lines 
with fine increments? I have read the manual over and over, and its not 
immediately obvious. Is it even possible? I am not referring to baseline 
skip, but rather to being able to have control over spacing of lines in 
a title page, for example.

Andrew