Fill the bottles a little less than half full. The water should be below the largest part of the bulb; stop the bottles with cotton, and over the top of each one invert a tin cup. Individual timbale-molds may be used. Cover the bottom of a tub with ice and salt, place the bottles on it, leaving some space around each one, then fill the tub with ice and salt, the same as in packing ice-creams, and cover it. Within two or three hours the water will become frozen. Care must be taken that the water in the tub is never high enough to flow into the top of the carafes. When ready to serve, wipe the frozen carafes and fill them with ice water.