Indus weights and measures

The weights

Indus weights are typically cubes of chert, finely finished and unmarked. They follow a regular series: the smaller weights double in a binary progression, and the larger ones increase by decimal multiples of a unit.

The consistency is the point. Weights from Mohenjo-daro and Harappa in ancient India (modern-day Pakistan), from Lothal, and from sites in between conform to the same standard within close tolerances, over a period of centuries and an area larger than western Europe.

Length

Linear measurement is attested by graduated scales, including a shell scale from Mohenjo-daro and an ivory scale from Lothal, marked in fine regular divisions. The proportions of baked brick — consistently close to 1:2:4 — imply a shared standard of length as well, and attempts have been made to derive a unit from brick dimensions and building plans.

What it implies

Standardisation of this kind requires enforcement, or at least a strong shared convention with some means of checking. It is among the strongest arguments for a coordinating authority across the Indus zone, and it also implies commerce conducted by weight rather than by bulk or barter alone.

Weights have been found at city gateways and in what appear to be merchants' premises, consistent with their use in assessing goods entering a settlement — possibly for taxation, though that is an inference.

Afterwards

The system did not survive the urban phase. Later South Asian weight standards do not continue it, which is one of the clearer indications that the collapse of the Indus cities involved a real institutional discontinuity rather than a simple change of settlement pattern.