I keep dreaming of my father's briefcase

I'm standing in his study at 4am, sorting letters by smell — tobacco, then rain, then the faint cedar of the coat closet. The briefcase is on the desk, unlatched, and I know I'm not supposed to open it, but I do, and inside is not paper but the hum of the kitchen at 5am, the one I've been trying to catalogue all week. I wake up before I find out whose hum it is.