Verse 21

क्षणार्धेन त्वपां शैत्यं जलसंवित्ततो भवेत् ।ततस्तादृग्गुणगतं मनो भावयति क्षणात्

In plain words

In but half an instant the coolness of the waters, and thence the cognition of water, would arise. Then mind, having come to such a quality, conceives, in an instant,