For cutting a glass bottle, a small jet made by drawing out a glass tube, or the mouthpiece end of a clay tobacco pipe should be connected to the gas supply by means of a rubber tube. Stand the bottle on a table and fill it with water to the height at which the bottle is to be cut, and make an ink mark around the bottle at the level of the water. Now empty the bottle, and with a triangular file make a deep cut on the lip of the bottle and, having lit the gas-jet, place it on the mark; after a few seconds remove the flame, and touch the part with a match stalk wetted; a crack will form at once, or after two or three trials. Now place the flame in front of the crack and lead it down the neck of the bottle to the ink mark, then right round the bottle.