अधोलोकवर्णनम् (Adholoka-varṇana) — Description of the Lower Worlds and Cosmographic Measures
दशपञ्च मुहूर्ताह्नो मुहूर्त्तास्त्रय एव च / दशपञ्चमुहूर्त्त वै ह्यहर्वैषुवतं स्मृतम्
daśapañca muhūrtāhno muhūrttāstraya eva ca / daśapañcamuhūrtta vai hyaharvaiṣuvataṃ smṛtam
Daytime consists of fifteen muhūrtas, and (the night too) is reckoned in three praharas. A day of fifteen muhūrtas is remembered as viṣuvat, the equinoctial measure.