"specifies which edge to use to display labels for the second axis.
" (or any abbreviation) can be
supplied for this attribute. The default is usually
" for the first axis and
" for the second axis. However, if exterior labelling was requested (see the
Labelling attribute) but cannot be produced using these default Edge values, then the
default values will be swapped if this enables exterior labelling to be produced.
In some circumstances, numerical labels will be drawn along internal grid lines instead of at the edges of the plotting area (see the Labelling attribute). In this case, the Edge attribute only affects the placement of the descriptive labels (these are drawn at the edges of the plotting area, rather than along the axis lines).