I am trying to sort two columns at the same time.  

I understand the basic sorting technique but am having trouble when it
comes to sorting the second column.
I have an x coordinate column and a y coordinate column.  I want to
have the spreadsheet display the records in order of x,y coordinate
from upper left to lower right.  That would mean sorting the x values
ascending then the y values descending.  I had hoped that the result of
the sort would be sequential x values followed by the next further down
y values continuing the increas, left-to-right of the x values.  But
this is not happening.  I don't know why.  Any ideas?

THanks

Max