Actually, Geoff, you'll find it's "hamper sand", so-called because it was derived from the use of sand kept in a small wicker receptacle, which was frequently misplaced. It was required when there was an unsightly blot, as a form of early blotting paper. Obviously when everyone tried to write this new-fangled shorthand thingy it was much in demand in the scriptorium. Hence the cry was frequently heard, in tones of urgency, " 'Ampersand! 'Ampersand!", which became attached to the symbol itself.