An Encyclopaedia of Indian Archaeology v1.c9.s9.35

v1.c9.s9.35

The literacy of the Indus people was not confined to reading and writing but extended to the third ‘R’, *viz.* arithmetic. This is duly reflected not only in the standardization of brick sizes (40 × 20 × 10 cm or 30 × 15 × 7·5 cm, the ratio being invariably 4:2:1) or the width of streets (as referred to earlier in respect of KALIBANGAN) but also in the weights and measures used by these people. Usually cubical in shape and made variously of chert, limestone, gneiss, chalcedony, etc., the weights [6.29] followed a binary system for the lower denominations and a decimal one higher up, the ratios being 1, 2, 8/3, 4, 8, 16, 32, 64, 160, 200, 320, 640, 1600, 3200, etc., up to 12800. Such a set and well-defined system is rather unique for the ancient world. Graduated scales [6.29] have been discovered at Mohenjo-daro, LOTHAL and KALIBANGAN, though these are not always complete. Likewise there is a bronze rod from Harappa which also bears markings at regular intervals. Put together, the evidence suggests that the Indus people used a ‘foot’ of about 33 cm to 33·5 cm, as well as a ‘cubit’ measuring about 51·6 to 52·8 cm.