History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s2.t4.50

v1.c13.s2.t4.50

Figs. 23 to 25 show photographs of different types of furnaces which were in operation during 17th to 19th century. All these furnaces had two holes at the bottom, one for introducing the blast and the other for removing the molten slag. Generally a slanting platform of bamboo, lined with mud, was prepared at the mouth of the furnace to preheat the charge and to push it inside the furnace. A picture of a bowl type furnace which the author studied in 1981 is found at Lohārpārā in the district of Bastar. The line diagram shown in Fig. 26 gives the details of this furnace made in one of the walls of a pit below the ground level. Fig. 27 shows a line diagram of a twin hearth furnace described by Buchanan which was capable of Fig. 20. Reproduction of wall painting from an iron working site in Japan. This painting shows that Japanese craftmen also worshiped ‘Lord Asura’ as in India producing 250 kg of iron per day in the Malabar area. The furnace was fitted with more than one pair of bellows, and peep holes were suitably located to monitor the temperature inside the furnace. Mahamud(1988) has described a furnace from Assam which is asymmetrical in design as shown in Fig.28. One of the walls of this furnace is slanting and this was probably designed to smelt Magnetite sand. Table 3 gives the detailed dimensions of most of these furnaces as available in the literature.