The weight of an empty envelope

An original narrative about an invented keepsake.

The envelope contained nothing. I held it open beneath the lamp, expecting a photograph to slide from a corner, but there was only a pale rectangle where the paper had once lain against paper.

On the front, my grandfather had written my old address. The house number leaned into the street name, as it always had when he ran out of room. I could hear the little impatient breath he made before beginning a second line. The stamp had been peeled away. A crescent of its edge remained, rough beneath my thumb.

My brother asked whether I wanted him to throw it out. I folded the flap along its existing crease and put the envelope beside the letters we were keeping. It was empty in the way an abandoned room is empty: there was nothing to carry away, but someone had unmistakably been there.

How does the writer give significance to the apparently empty envelope?