Random Processes

Abstract

If a bottle of ether is opened at one end of a room, we can soon smell the vapors at the other end. But the ether molecules have not traversed the room in a straight line, nor in a single bound. They have undergone myriad collisions with air molecules, bouncing first one way, then another in a random walk that takes some molecules back into the bottle from which they came, others through a crack in the door, and others yet into the vicinity of an observer’s nose where they can be inhaled to give the sensation of smell.