History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s4.50

v1.c13.s4.50

without any significant deformation. These crucibles were used only once and then discarded. Recent mineralogical study of these crucibles have shown the presence of graphitized Silica and Mullite minerals in these crucibles. These minerals were generally developed by the mixture of clay with rice husk and iron oxide etc. and giving a precisely controlled firing treatment. The smelters and smiths had mastered the technique of controlling temperature and atmosphere of the furnaces by the study of colour and control of the air supply.