Minerals and Metals in Ancient India v2.c39.s1.2

v2.c39.s1.2

The use of a winnow must have been very ancient, this having been depicted in a Harappan seal. The Atharva Veda was the first literature in which this is mentioned as a *śūrpa*. The hymns 9.6.15-16 (and also 11.2.1 and 11.8.3-4) describe the roles of the mortar and pestle in corn pounding, followed by the use of a *śūrpa* or a winnow in separating the grain from the husk. Now we know that the principle of separation is based on the non-terminal pneumatic settling of particles. This technique as well as the hydraulic (in water) gravity-settling process must have been used to separate the fine/coarse and light/heavy mineral particles. This separation process was recognised as a step of purification: *śūrpam pavitram tuṣā* (AV, 9.6.16) for which air served as the medium of separation: *śūrpagrāhī vātoipāvinak* (AV, 11.8.4).