Matsya Purana — Measures of Time: Caturyuga Computation
काष्ठा निमेषा दश पञ्च चैव त्रिंशच्च काष्ठां गणयेत्कलां तु त्रिंशत्कलाश्चैव भवेन्मुहूर्तस् तैस्त्रिंशता रात्र्यहनी समेते //
kāṣṭhā nimeṣā daśa pañca caiva triṃśacca kāṣṭhāṃ gaṇayetkalāṃ tu triṃśatkalāścaiva bhavenmuhūrtas taistriṃśatā rātryahanī samete //
Fifteen nimeṣas make one kāṣṭhā; thirty kāṣṭhās are counted as one kalā. Thirty kalās make one muhūrta; and by thirty muhūrtas, the night and the day are completed.
This verse does not describe Pralaya directly; it provides the precise, traditional scale of time-units used in Purāṇic cosmology, which underlies later discussions of cosmic cycles such as creation and dissolution.
By defining kalā and muhūrta, the verse supports dharmic governance and household discipline: daily rites, administrative schedules, fasts, vows, and judicial or royal activities are traditionally organized by muhūrta-based timekeeping.
In ritual and Vāstu practice, selecting an auspicious muhūrta is essential for temple building, foundation-laying, consecration (pratiṣṭhā), and major saṃskāras; this verse supplies the base conversions needed for such muhūrta calculations.