Before a taddhita affix having an indicatory ñ , ṇ or k in a dvanda samāsa of god-names, the vṛddhi is not substituted for the first vowel of varuṇa when a long vowel precedes it.,
As ऐन्द्रावरुणम्, मेत्रावरुणम् from इन्द्रवरुणौ &c. 6.3.26. But आग्निवारुणीम् in आग्निवारुणीमनड्वाहीमालभेत् when a short vowel precedes it. This word is derived from the compound word अग्नीवरुणौ the इ of अग्नि being lengthened by 6.3.27. But in forming a Taddhita- derivative from this word, the long ई is shortened by 6.3.28, and therefore, it cannot be said that a long vowel precedes वरुण ॥,