138 Domestic Science 



about 20" long must first be procured. Heat the 

 tubing at a point about 2" from one end in a Bunsen 

 flame, the tubing being held as shown in Fig. 39. 

 During the heating the tube should be rotated back- 

 wards and forwards between the fingers so that it, is 

 evenly heated throughout. When the heated portion 

 of the glass has become thoroughly soft, remove it 

 from the flame, and gently pull each end of the tube 

 in a horizontal direction till the softened part has 

 been stretched into a small thin tube about 6 to 8 

 inches long. Allow the tube to become quite cold. 

 Cut the tubing by making a scratch on it with a sharp 

 file at the end of the drawn-out portion nearest the 

 longer part of the tube, putting a thumb and forefinger 

 on each side of the scratch, with the mark on the side 

 of the tube away from the body, and snapping the glass 

 as one breaks a small twig. The longer piece of 

 tubing will then present the appearance shown 

 in Fig. 40. A bulb is next blown at the 

 pointed end of this tube by carefully carrying 

 out the following instructions. Heat the 

 pointed end by holding it just above the blue 

 inner cone of a strong Bunsen flame, con- 

 tinually rotating the tube as before. The 

 end of the tube will become closed by the 

 glass, when sufficiently softened, gradually 

 forming a small semi-liquid drop at the end of 

 the heated part. At this stage remove the 

 tube from the flame, and gently blow with 

 the mouth at the open end of the tube. AS 

 the tubing cools, the strength of the blast Fig. 40 - 

 may be increased. This should result in the 

 formation of a small swelling at the closed end. 

 Repeat the heating till the tube is again thoroughly 



