extracting coordinates

Hi,

I'm going through some initial data inspection, and working through steps in the 
"Applied Spatial Data analysis with R" book.
Following steps in Ch. 2 of the "Applied Spatial Data analysis with R" book, I 
was able toextract a set of coordinates from my
SpatialPoints object just fine. The object returned looks right - the 
coordinates are extracted correctly, but my bounding box does
not change. The same min/max for coords.x1 and x2 get returned instead of a new 
bounding box that reflects the selection.

library(sp)
data(meuse)
coordinates(meuse)=~x+y
bbox(meuse)

bbox(meuse[1,])

Not sure what I'm missing, would appreciate any help - I apologize if this is 
overly simple!

thanks,
Robin