In the list view, the sort order is indicated by an arrow in the column header.
For string columns, such as the filename, if the arrow points down, the strings
are sorted increasing (a to z) when going the list. Number columns, such as as
the filesize, however. are sorted decreasing for this orientation of the arrow.
This is inconsistent, not only within nautilus itself, but also with regard to
the GtkFileChooser widget.

Seen with nautilus 2.10.1.