Mediaeval Sinhalese Art c22.14

c22.14

The essential parts of the furnace are the well or furnace proper; a wall of wattle and daub protecting the bellows blower from the heat of the fire; and the bellows behind this wall. The well has two openings, one in front, from which the slag runs out, and through which the bloom of iron is ultimately extracted; and a smaller opening behind, through which a blast of air from the bellows is forced into the well. The bottom of the furnace is covered with sand, which also fills up the front opening. A charcoal fire is started at the bottom of the well and covered with layers of ore and charcoal until the well is filled, a continuous blast of air from the bellows keeping up the fire meanwhile. Additional ore and charcoal are added as the work proceeds, the stoking with charcoal, together with the occasional letting out of slag, being sufficient occupation for one man. The bellows, from which a continuous blast is kept for three hours or more, are worked by two other men, who share the work by turns; they are of a primitive but ingenious type. Behind the furnace are embedded vertically in the ground two logs of wood, about 17 inches in diameter, and hollowed out above to a depth of three or four inches; over each of these a piece of deer skin is tied, having a small hole near its centre, and at the centre a piece of cord attached, which latter is fastened six or seven feet above to a springy stick, the lower end of which is embedded in the ground. From each of these two sections of the bellows a small pipe conducts the blast into the hole leading to the well of the furnace. The bellows blower stands with his feet, one on each of the deer skins, facing the wall and lifting and putting down his feet in turn, drives a continuous blast of air into the furnace; for as he puts down his foot to press out the air from one skin, he covers the hole in it with the sole of his foot; and meanwhile the other skin is filled with air through the hole, which is uncovered when he lifts his foot, the skin being pulled up by the tension of the bent stick upon the string. On either side of the blower is a stake which he grips hold of, and which a strap is fastened that passes round behind him and supports his back.