Note 958 — Chapter IX · LEUKIPPOS OF MILETOS
Reading edition
In Aet. i. 12, where the placita regarding the heavy and light are given, no philosopher earlier than Plato is referred to. Parmenides (fr. 8, 59) speaks of the dark element as ἐμβριθές. I do not think that there is any other place where weight is even mentioned in the fragments of the early philosophers.