BROWNIAN       :

               As in brownian motion entirely random movement,

               this way and that, in a liquid or in a gas. It

               was first observed by mr Brown who saw strange

               movements of tiny pollen particles in water

               with a microscope. This strange jerky motion

               has since been explained as being due to the

               smoke or dust particles being bumped into all

               the time by the molecules of the liquid or the

               gas, sometimes a few more are hitting it from

               one side, causing the fleck of dust to move in

               the opposite direction, and at other times a

               few more may nudge it from another side.