Abstract: Dry sand is "rained" or pluviated into a receptor container used in the sy of soil mechanics. A supply vessel in the shape of an open-top rectangular box has four vertical side walls, a perforated bottom tray, and a slidable perforated tray in contact therewith, whereby sand flows by gravity from the supply vessel through perforations in the stationary and slidable trays and "rains" or pluviates into the receptor container when the slidable tray is in the "open" position, and sand is blocked from flowing from the supply vessel with the slidable tray in the "closed" position.