The thermal form of this process subject to the Soret effect was investigated by Clusius and Dickel using an insulated column. The force of a “self” form of this process is given by the derivative of chemical potential with respect to distance. The Schmidt number relates the kinematic viscosity of a fluid to this process. The Wilke–Chang correlation can be used to estimate this process and uses a solute–solvent interaction factor. Random walks were related to a parabolic (-5[1])equation (10[1])named for this process by Einstein. (10[1]-5[3])The letter D represents a coefficient of this process in two laws of it named for Fick. Solvent undergoes a specific form of this process across membranes in osmosis. For 10 points, name this general process where particles travel down concentration gradients. ■END■ (10[3]0[1])