Vaisesika Sūtra 3.2.02

तस्यद्रव्यत्वनित्यत्वे वायुना व्याख्याते ॥२॥

tasya-dravyatva-nityatve vāyunā vyākhyāte ॥2॥

[तस्य (tasya) - of it; द्रव्यत्व (dravyatva) - substantiality; नित्यत्वे (nityatve) - and eternality; वायुना (vāyunā) - by air; व्याख्याते (vyākhyāte) - are explained;]

Its substantiality and eternality are explained by breath.