The tube, condensation chamber, and jet are combined in the ordinary Black's blowpipe, such as is used for blowpipe tests in qualitative analysis; it consists of a conical tin tube having a mouthpiece at the small end and a side tube which carries a brass jet. A support for such a blowpipe may be cut out of a piece of brass or tin-plate, and should be fastened to a small, flat, wooden board. A source of flame may consist of an ordinary brass elbow, such as is used on gas fittings, and into which a piece of thin brass tube (the body of a fish-tail burner from which the perforated non-metallic plug has been removed will serve quite well) has been fitted. It is an advantage to flatten the brass tube somewhat and to file the flattened end to a slope which corresponds with the angle at which the blowpipe jet enters the burner. The whole source of the flame should be mounted on a separate base, in order that it may be moved while adjusting the apparatus to the best relative positions of flame and blowpipe jet. The complete apparatus is shown by _a_, Fig. 16. [Illustration: Fig. 16] In order to take full advantage of this blowpipe, it is desirable that the student should learn to maintain a steady steam of air with his mouth and, at the same time, be able to breathe. This requires a little practice. As a first exercise in breathing, before trying to breathe while using the mouth blowpipe, the student should close his mouth and inflate his cheeks with air; now, still keeping his cheeks tightly inflated, he should attempt to breathe through the nose. At first, this may be found rather difficult, but it becomes remarkably easy after a little practice. When he has mastered this, the student may practise the same operation, but with the blowpipe. It is important to bear in mind that the cheeks, not the lungs, form the reservoir for air used in maintaining the blowpipe flame. After a while, the student will find that he can maintain a steady air pressure and yet breathe with complete comfort. In adjusting the flame, care should be taken not to blow so hard as to produce a ragged and noisy cone of fire. A small jet, such as that commonly used on a mouth blowpipe, will with care give a pointed and quiet flame, having an appearance similar to that shown in the illustration. With a blowpipe like this, it is quite easy to seal glass tubes up to an inch in diameter, to join tubes up to half an inch in diameter, to bend tubes, to blow small bulbs, and to make the simpler forms of internal seal; but the provision for condensation of moisture is not ideal, and prolonged use of such a blowpipe also tends to produce undue fatigue.