Brahma Sutras
ॐ सूक्ष्मं प्रमाणतश्च तथोपलब्धेः ॐ ॥ ४-२-९॥
That fire (as also other elements) is minute in its nature, as also in size, because it is seen to be so.
english translation
OM sUkSmaM pramANatazca tathopalabdheH OM ॥ 4-2-9॥
hk transliteration by Sanscript