Many industrial and food powders were studied for structure and strength under normal stress at varying moisture content. The increase in humidity of the glass beads (0.25-0.5 mm), polyester (150-250 mu m), potato starch (36-75 mu m) and semolina (100-200 mu m) powders resulted in an increase in their shear strength and in a redn. of unfavorable oscillations. The occurrence of a "lubricating effect" in all materials studied was obsd.