Astanga Hrudaya
द्रव्यमूर्ध्वगमं तत्र प्रायोऽग्निपवनोत्कटम्। अधोगामि च भूयिष्ठं भूमितोयगुणाधिकम्॥११॥
Properties of Dravyas- Fire (Agni) and Pavana (air) predominant substances generally have the property of moving upwards. Bhumi (earth) and Toya (water) dominant substances generally have the property of moving downwards
english translation
dravyamUrdhvagamaM tatra prAyo'gnipavanotkaTam। adhogAmi ca bhUyiSThaM bhUmitoyaguNAdhikam॥11॥
hk transliteration by Sanscript