The Nether-worlds :* Manifestation of the Luminaries - Verse 168

Fifteen Nimesas (winking time of the eye) make one Ka$tha, thirty Kasthas make one Kala; thirty Kalds make a its circle is lighted (that gets light) while on the other side of this dividing mountain, there is utter darkness. 342 Vayu Purana Muhurta and thirty Muhurtas make (a full day consisting of) a night and a day.