4 i8 PRACTICAL ORGANIC CHEMISTRY considered further. The tube, throughout the whole of its subsequent mani-pulation in the blowpipe flame, must be kept steadily and regularly rotated in order to ensure uniform heating and treatment: this point will not therefore be further emphasised. Now heat the tube in a small hot flame about the portion aa until the pointed tail, which has hitherto been used as a handle, can be drawn off, leaving the tube closed as shown in B. By using this method, the formation of a heavy blob or button of glass at the extreme end of the tube (a source of great subsequent weakness) can easily be avoided. Now heat the closed end of the tube in a rather larger flame until the end is uniformly soft, and then carefully blow down the tube, keeping the latter rotated gently in the mouth whilst the pressure is applied. By these means, a rounded end of uniform thickness, as in C, is obtained. The heating and subsequent blowing down the rotating tube should be repeated until a really satisfactory
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.