[R] spineplot (graphics package): how to control font size?

[Paul Shannon]

I cannot modify the font size of the standard text items for the  
splineplot function
found in the standard graphics package.  Here is a tiny example, in  
which
I try (but fail) to make the main title large.

     tbl = read.table ('http://www.ggobi.org/book/data/tips.csv',  
sep=',', header=T)
     spineplot (table (tbl$DAY, tbl$SEX), main='TIPS', cex.main=3)

None of the other 'cex' parameters seem to work either, but cex.main  
is probably
a sufficient example.

Any tips for me?  Thanks!

  - Paul