say that thirty years ago nearly all the iron worked by the tribes of the interior of Borneo was from ore found in the river beds.  At present most of the pagans obtain the metal from the Chinese and Malay traders, but native ore is still smelted in the far interior. [230] Foreign iron is now used by the Battak of Sumatra, but deserted iron-works are known to exist in their country, while the Menangkabau still possess smelting furnaces. [231] It seems probable that the whole industry had a common source, and was spread or carried as a unit, but when trade relations made the arduous work of mining and smelting unnecessary, it was quickly given up.  That native iron might have supplied the needs of many Philippine tribes, including the Tinguian, is certain, for important deposits of magnetite and hematite are found in Abra, in Ilocos Norte, Angat, Bulacan, Albay, and other parts of the Islands. [232] On several occasions, when on the trail, the natives have called our attention to boulders, apparently of hematite, which they recognized as iron.

The smithies are small structures with grass roofs, but no sides or floors (Plate LXII).  At one end is a raised bamboo bench in front of which stands the forge.  This consists of two upright wooden cylinders, usually logs hollowed out, known as po-opan. In each of these is a piston or plunger (doeydoyog) at the lower end of which is a wooden ring packed with corn husks and chicken feathers.  When this is pushed downward in the cylinder, it compresses the air and forces it out of the small opening in the base, but when it is drawn up, the packing collapses and allows the plunger to be raised without effort.  These pistons are worked so that one is rising, while the other is falling.  The cylinders stand in a wooden block out of which bamboo tubes (tolongon) conduct the air into a tube of fire clay (ibong), and this in turn carries it into the charcoal fire.  There are no valves, as in the Chinese bellows, but the bamboo tubes fit loosely, and the fire is not drawn back.  Near to the hearth is a stone anvil (dalisdisan), while a heavy stone hammer, a small iron hammer, and iron pinchers complete the outfit.

The fire is lighted, and the operator sitting on the bench alternately raises and lowers the plungers in the cylinders until the fire burns brightly; then the smith puts metal into the coals and allows it to remain until it reaches a white heat.  It is then removed and placed on the anvil, where his helper beats it out with the large hammer.  This is a stone weighing twenty or more pounds, fitted inside the handles so that it can be used with both hands.  As a rule, it is swung between the legs, and is allowed to strike the metal as it descends, but some of the men raise it above the shoulder and strike a much more powerful blow.  If two pieces of metal are to be welded together, as is often the case when broken caldrons are used, they are laid, one overlapping the other, and are held together with damp fire-clay.  In this condition they are placed in the fire and heated, and are then beaten together.  It often takes several firings to bring about a perfect weld.