History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c14.s1.10

v1.c14.s1.10

A complete set of three discs, found at Mathura, have the top and bottom ones blank on their exposed sides. Their inner faces bear coin sockets, while the central discs have coin-impressions on both faces. Traces of luting on the outer side indicate that these were plastered over. A part of the edge of the middle disc was cut away into a ‘V’-shaped notch, with a straight channel on each face leading from the notch to a point just beyond the centre. From this main channel four short branch channels came off at straight angles, two from either side of it. The ends of these four channels and that of the main channel itself communicated with the five coin sockets.