Heat a piece of No. 6 in the blowpipe flame at a length of 7½ inches and draw it out into a nozzle; smooth the other end in the lamp flame. Use the same plunger as in Experiment 48, and your syringe is made (Fig. 69). Try it out with water. Experiment 50. To make a third syringe. Heat a piece of No. 6 tube in the blowpipe flame at a length of 7½ inches, draw it out, and close the end, then smooth the other end. Now to make a plunger: Heat a piece of No. 2 tube 8½ inches from one end in the lamp flame, draw it out into a nozzle, and break it off, leaving a small hole at the end of the nozzle. Smooth the other end in the lamp flame, flare it out slightly, allow it to cool, dip it into water and insert it into a small wet coupling. [Illustration: FIG. 70 A THIRD SYRINGE ] Now fill the large tube with water and insert the coupling plunger (Fig. 70). Do you get a fine long stream? Experiment 51. To make a diablo whistle. Use the No. 6 tube and the No. 2 plunger from Experiment 48, arrange as in Fig. 71, blow across the top, and move the plunger up and down. Do you get a most diabolical sound? [Illustration: FIG. 71 THE DIABLO WHISTLE ] The sound is produced by the vibration of the air column between the top of the tube and the top of the plunger. Do you find that the pitch of the note is higher the shorter the air column? Experiment 52. Fun with the diablo whistle. Start with the air column long and blow the note, shorten it a little and blow the next note, continue, and try to blow the eight notes of an octave. [Illustration: FIG. 72 JOINING TWO TUBES ] Try to play a tune. Try to make the most weird sound you can. Experiment 53. To join two tubes end to end. Take a piece of No. 2 tube about 7 inches long, close one end, smooth the other, and when cool cut the tube at the middle. [Illustration: FIG. 73 WORKING THE JOINT ] Now join these two pieces as follows: Hold the ends opposite each other near the top of the lamp flame (Fig. 72), rotate constantly, and when nearly red hot bring the ends accurately together in the flame, press together slightly, draw out slightly, and remove from the flame. The ends are now stuck together, but the glass is in a slight lump around the joint and if allowed to cool will crack very easily. It is necessary to work the glass back and forth to get rid of the lump and to make the glass uniform on both sides of the joint. Do this as follows: Heat one third of the joint in the blowpipe flame (Fig. 73), and when red hot blow a slight bulge. Now turn the joint one third, heat the next third red hot and blow a slight bulge. Repeat with the remaining third. [Illustration: FIG. 74 JOINING TUBES OF DIFFERENT SIZES ] Now heat the first third again until it is red hot and shrinks, then blow a slight bulge again. Repeat this with the other two thirds.