3
Philinus
Theon replied, When of the primal and simplest elements in Nature, as they are called and actually are — fire, earth, air, and water — there is none other that comes near to the bronze or is in contact with it, save only air, it is clear that the bronze is affected by this, and that because of this it has acquired whatever distinctive quality it has, since the air is always about it and environs it closely. Cf. Life of Coriolanus, chap. xxxviii. (232 a). Of a truth All this I knew before Theognis’ day,Kock, Com. Att. Frag. iii. p. 495, Adespota, no. 461. Plutarch quotes this again in Moralia, 777 c. as the comic poet has it. But is it your desire to learn what property the air possesses and what power it exerts in its constant contact, so that it has imparted a colouring to the bronze?
As Diogenianus assented, Theon said, And so also is it my desire, my young friend; let us, therefore, investigate together, and before anything else, if you will, the reason why olive-oil most of all the liquids covers bronze with rust. For, obviously, the oil of itself does not deposit the rust, since it is pure and stainless when applied.
Certainly not, said the young man. My own opinion is that there must be something else that causes this, for the oil is thin, pure, and transparent, and the rust, when it encounters this, is most visible, but in the other liquids it becomes invisible.
