This, then, is what seems to follow from the criticisms of Aristotle and from the nature of the case; but it will be observed that it is not consistent with Zeller’s opinion that the original motion of the atoms is a fall through infinite space, as in the system of Epicurus. Zeller’s view depends, of course, on the further belief that the atoms have weight, and that weight is the tendency of bodies to fall, so we must go on to consider whether and in what sense weight is a property of the atoms. [Sidenote: The weight of the atoms.] 179. As is well known, Epicurus held that the atoms were naturally heavy, and therefore fell continually in the infinite void. The school tradition is, however, that the “natural weight” of the atoms was an addition made by Epicurus himself to the original atomic system. Demokritos, we are told, assigned two properties to atoms, magnitude and form, to which Epicurus added a third, weight.[956] On the other hand, Aristotle distinctly says in one place that Demokritos held the atoms were heavier “in proportion to their excess,” and this seems to be explained by the statement of Theophrastos that, according to him, weight depended on magnitude.[957] It will be observed that, even so, it is not represented as a primary property of the atoms in the same sense as magnitude. Footnote 956: Aet. i. 3, 18 (of Epicurus), συμβεβηκέναι δὲ τοῖς σώμασι τρία ταῦτα, σχῆμα, μέγεθος, βάρος. Δημόκριτος μὲν γὰρ ἔλεγε δύο, μέγεθός τε καὶ σχῆμα, ὁ δὲ Ἐπίκουρος τούτοις καὶ τρίτον βάρος προσέθηκεν· ἀνάγκη γάρ, φησί, κινεῖσθαι τὰ σώματα τῇ τοῦ βάρους πληγῇ· ἐπεὶ (“or else”) οὐ κινηθήσεται; _ib._ 12, 6, Δημόκριτος τὰ πρῶτά φησι σώματα, ταῦτα δ’ ἦν τὰ ναστά, βάρος μὲν οὐκ ἔχειν, κινεῖσθαι δὲ κατ’ ἀλληλοτυπίαν ἐν τῷ ἀπείρῳ. Cic. _de fato_, 20, “vim motus habebant (atomi) a Democrito impulsionis quam plagam ille appellat, a te, Epicure, gravitatis et ponderis.” These passages represent the Epicurean school tradition, which would hardly venture to misrepresent Demokritos on so important a point. His works were still accessible. It is confirmed by the Academic tradition in _de Fin._ i. 17 that Demokritos taught the atoms moved “in infinito inani, in quo nihil nec summum nec infimum nec medium nec extremum sit.” This doctrine, we are told, was “depraved” by Epicurus. Footnote 957: Arist. _de Gen. Corr._ 326 a 9, καίτοι βαρύτερόν γε κατὰ τὴν ὑπεροχήν φησιν εἶναι Δημόκριτος ἕκαστον τῶν ἀδιαιρέτων. I cannot believe this means anything else than what Theophrastos says in his fragment on sensation, § 61 (R. P. 199), βαρὺ μὲν οὖν καὶ κοῦφον τῷ μεγέθει διαιρεῖ Δημόκριτος.