SB 3.11.5

Two paramāṇus make an aṇu. Three aṇus make a trasareṇu. The trasareṇu is perceived by the eye, since if follow the air currents in the rays of the sun entering through a lattice. Two paramāṇus makes one aṇu. Three aṇus make one trasareṇu. The trasareṇu can be perceived. It can be known as it follows after the air because of its lightness, in the rays of the sun entering through a lattice. Another version has na tu gām agāt: it does not go to the earth. It remains moving about. What is the evidence of the aṇu and paramāṇu? The trisareṇu is the evidence. It is a common rule that without having dense and numerous parts, the possessor of the parts cannot be seen. The trisareṇu is the possessor of parts, with three gross aṇus as its parts. However the paramāṇus are not gross at all. Solidity involves many objects. Thus the grossness of the anu depends on the paramāṇu. This proves the existence of the paramāṇu. The visibility of the trisareṇu is not possible without solid parts. Making the aṇu solid requires only two paramāṇus, not three or four, using the logic of accepting the first possibility. Just as Jaimini argues that three partridges are the minimum requirement for sacrifice, [Note: Kapiṣjala-nyāya] so a minimum of three aṇus produce density so that the trasareṇu can be seen.