These were used to break up ice cubes. For right-handers, one held the cube in the palm of the left hand. The cube was then struck with a downward stroke, beginning at a distance of about 12 inches from the cube and using a wrist snap. The cube fractured into 3 - 5 main groups which were then dumped into the glass. This was done with several cubes in succession until the glass was filled with a sufficiency of ice shards. Liquor poured over the cubes would chill rapidly because of the increased surface area of the cooling medium, e.g. the ice.
