The Upanishads, Part 1 (SBE01), by Max Müller, , at sacred-texts.com
1. Let a man meditate on the fivefold Sâman as rain. The hiṅkâra is wind (that brings the rain); the prastâva is, 'the cloud is come;' the udgîtha is, 'it rains;' the pratihâra, 'it flashes, it thunders;'
2. The nidhana is, 'it stops.' There is rain for him, and he brings rain for others who thus knowing meditates on the fivefold Sâman as rain.