Experiment 19. To make a submarine.
Close one end of a piece of No. 2 tubing as described above, but leave the end somewhat pointed (1, Fig. 32). Heat the tube on one side at a distance ½ inch from the end and blow a bulb about ½ inch in diameter (2). Heat the tube ¼ inch from the bulb, draw it down into a fine tube, and break off the tube, leaving a small hole in the end (3). Place the submarine in a glass of water, and if it floats it is complete.