Chap. 1.] Origin of the Valve.—African Bellows. 235
A largess to Ulysses he consigned,
And in a steer’s tough hide enclosed a wind. Met. xiv.
The goldsmiths’ bellows of Barbary consists of a goat’s skin, having areed inserted into it: ‘he holds the reed with one hand and prgsses thebag with the other.’ (Ed. Encye. vol. iii, 258.) The Damaras, a tribe ofnegroes in Southern Africa mentioned by Barrow, manufacture copperrings, &c. from the ore. The bellows they use, he observes, “is made ofthe skin of a gemsbok, (a species of deer) converted into a sack, with thehorn of the same animal fixed to one end for a pipe.”
Simple instruments of this description have always been applied toeject liquids. Small ones were commonly used by ancient physicians inadministering enemas; a purpose for which they are still used. Largeones were recommended by Apollodorus the architect, a Contemporary ofPliny and Trajan, as a Substitute for fire engines, when the latter werenot at hand. When the upper part of a house was on fire, and no ma-chine for throwing water to be procured, hollow reeds, he observed,might be fastened to leathern bags filled with water, and the liquid pro-jected on the flames by eompressing them.
As the current of wind from a single sack or bag, necessarily ceasedas soon as it was collapsed, some mode of rendering the blast continwouswas desirable ; and in the working of iron indispensible. The most ob-vious plan to accomplish this was to make use of two bags, and to workthem so that one might be inhaling the air, while the other was expellingit—that is, as one was distended, the other might be compressed. Thisdevice we shall find was very early adopted, and by all the nations ofantiquity.
But by far the most important improvement on the primitive bellows orbag, was the admission of air by a separate opening —a contrivance thatled to the invention of the valve, one of the most essential elements ofhydraulic as well as pneumatic machinery. The first approach to theordinary valve, was a device that is still common in the bellows of someAfrican tribes. A bag formed of the skin of a goat, has a reed attachedto it to convey the blast to the fire ; and the part which covered the neckof the animal is left open for the admission of air. This part is gathered upin the hand when the bag is compressed, and opened when it is distended.