Bhagavatapurana 3.11.9

3.11.9

dvādaśārdha-palonmānaṃ caturbhiś catur-aṅgulaiḥ /
svarṇa-māṣaiḥ kṛta-cchidraṃ yāvat prastha-jala-plutam //

Verse 8. *V.* Here the measure of Time according to men is intended; hence it is said नॄणाम् *D.* the six Nadikas make one Prahara and seven make one Yama (याम) 9. A measure of capacity made of copper weighing 6 pollums, the sides being 4 times 4 inches high with holes made at the bottom by gold mashas,—the time taken by water to fill that vessel through those holes is said to be a Nadika.