An Encyclopaedia of Indian Archaeology v1.c16.s14.15

v1.c16.s14.15

The ware was baked in an enclosed baking device under a reducing atmoshpere. What was this baking device like? There are groups of potters in the Ganga valley and elsewhere who have a simple device for baking pots in a reducing atmosphere by using a mouthed, thick-walled, well-baked strong jar in which they stack their ready-to-bake vessels. The space inside the vessels and between them and the jar is filled with cow-dung cake powder and goat droppings. They then seal the jar with several layers of clay and cloth to make it completely airtight. The pots in the jar are then baked in a *gajaputa*, which is a well-known ancient high temperature heating device, described by Vāgbhaṭa (Dharmanand, 1962, pp. 151-2) as consisting of a pit of about 1 cubic m. At the bottom it is closely packed with cowdung cakes up to a height of 20 to 30 cm. The sealed jar containing the pots is placed in the centre of the pit above the cow-dung cakes. It is then fully surrounded with cow-dung cakes and some more cakes are piled up above the pit. Thereafter it is set on fire and allowed to burn first for a few hours slowly and then with strong heat for 8 to 12 hours. Within the jar the pots are baked in the reducing atmosphere of carbon monoxide. Under this condition red haematite is reduced to black magnetite. It is likely that this baking device was used in the manufacture of the PGW.