This section is from the book "Experimental Glass Blowing For Boys", by Carleton J. Lynde. Also available from Amazon: Experimental Glass Blowing for Boys.
Hold the small end of the blowpipe just inside the flame at one edge, about1/8 inch above the wick (Fig. 9), and blow air through the flame parallel to the top of the wick.
Keep your mouth closed on the blowpipe, breathe through your nose, and practice keeping a steady stream of air going for a long time. You will be able to do this with a little practice.
Do you observe that the blowpipe flame is pointed, also that it is made up of a pointed cone inside and a lighter-colored cone outside? The hottest part of the flame is inside the outer cone just beyond the point of the inner cone.
The blowpipe flame is hotter than the lamp flame because the heat of the burning alcohol is concentrated at one point by means of the air blast, and because the alcohol is more completely burned by the extra air.
 
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