BELLOWS, machine for blowing fire, so formed as, by being dilated and contracted, to inhale air by an orifice which is opened and closed by a valve, and to propel it through a tube upon the fire. The invention of bellows is ascribed to Anacharsis the Scythian, though probably it took place in different countries. The forms of bellows at present are very vari ous, as many. attempts have been made for the improvement of this highly important machine, which becomes necessary wherever a powerful flame is required in the arts. As mining was carried on at an early date in Germany, and great heat is required in smelting the ores and working the metals, various new kinds of bel lows were invented in that country, one of which consists of an empty box, which moves up and down in another, partially filled with water. Between the bottom of the empty box and the surface of the water is a space filled with air, which is driven out by the descent of the enclosed box. Bellows of very great power are generally called blowing-machines (q.v.), The common Chinese bellows consist of a box of wood about two feet long and one foot square, in which a thick, square piece of board, which exactly fits the internal cavity of the box, is pushed backward and forward. In the bot
tom of the box, at each end, there is a small conical or plug valve to admit the air, and valves above to discharge it. The common bel lows does not give a continuous blast but only a series of puffs. To remedy this two bellows were used, one filling while the other was blow ing. The double bellows was an even greater improvement. This machine has a third board placed between two main boards; this third board is fixed and both it and the lower board are fitted with valves opening inward. A weight on the lower board keeps the lower chamber filled with air and when raised the air flows into the upper chamber in which the noz zle is placed. A weight on the upper board tends to force the air from the upper cham ber through the nozzle in a continuous stream. However, the blast is not uniform and the use of the bellows is limited to domestic fireplaces and ordinary forges. Consult Weisbach, (Me chanics of Air Machinery' (New York 1905).