History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c14.s1.17

v1.c14.s1.17

A great advantage of the Rohtak system of casting coin was its capability of producing a very large number of coins in one single operation. However, an equally great disadvantage was that the moulds were broken and lost in that process. This drawback might not have been always faced in casting coins in moulds having one socket. At least we have evidence of producing coins in modern times from such ancient Roman moulds (Sahni, 1945, p.52). As part of the metal was likely to be lost in channels and before reaching sockets, it was difficult to control weight of each and every cast coin. This fact explains the divergence in weight of cast coins of apparently one and the same denomination. A part of the metal hardened in the channel leading to a coin socket in a mould which was sometimes left unseparated from the metal hardened in the socket. This distorted the shape of the coin produced from that socket.