The document summarizes Eyring's molecular theory of viscosity of liquids. According to the theory, molecules in a pure liquid are constantly moving within a "cage" formed by neighboring molecules. Occasionally, a molecule will gain enough energy to escape its cage and jump into an adjacent empty space. The viscosity of a liquid can be estimated based on the rate of these jumps and the average distance traveled during each jump. The document provides two example problems to estimate the viscosity of liquid benzene and water at different temperatures using data and equations from Eyring's theory.