Vaisesika Sūtra 5.2.07

वृक्षाभिसर्पणमित्यदृष्टकारितम् ॥७॥

vṛkṣābhisarpaṇam ityadṛṣṭakāritam ॥7॥

[वृक्ष-अभिसर्पणम् (vṛkṣa-abhisarpaṇam) - circulation in a tree; इति (iti) - thus; अदृष्ट-कारितम् (adṛṣṭa-kāritam) - caused by unseen force;]

Circulation in a tree is thus caused by unseen-force.