Blowpipe

an instrument for supplying a fine, steady jet of air. It consists either of a large tube with a small one joined to it at one extremity at right angles, or of a large tube drawn out into a fine curved tip. When held with the lips closed tightly around the large end, it constitutes, with the mouth cavity and flexible cheeks, a sort of bellows, by means of which an operator in the laboratory is able to create a steady stream of air. The blowpipe is used in chemical analysis and in mineralogy in connection with an alcohol or gas flame to produce an intense degree of heat. A loop of platinum wire or a piece of wood charcoal is generally used as a support. If a substance heated under the blowpipe gives a green color, it is likely to be copper; if blue, it may be cobalt; if violet, potash; if yellow, soda; if brick-red, lime, etc. The odor and the sort of ash, if any, obtained are also depended upon. This method of identifying substances is called blowpipe analysis. The action of the blowpipe is also secured by the use of a rubber bulb held in the hand, by weights, and by compressed air, gas, and other contrivances, especially in large iron works where a terrific blast of air is required.