[IDEM libro undecimo epistularum. ] §18.1.65.prConuenit mihi tecum, ut certum numerum tegularum mihi dares certo pretio quod ut faceres: utrum emptio sit an locatio? respondit, si ex meo fundo tegulas tibi factas ut darem conuenit, emptionem puto esse, non conductionem: totiens enim conductio alicuius rei est, quotiens materia, in qua aliquid praestatur, in eodem statu eiusdem manet: quotiens uero et immutatur et alienatur, emptio magis quam locatio intellegi debet.
[THE SAME, Letters, Book XI] An agreement was made between me and you, that you should give me a certain number of tiles at a certain price for doing this: is this a sale or a hire? He replied: if it was agreed that I should give you tiles made from my land, I think it is a sale, not a hire; for a hire of anything exists as often as the material in which something is performed remains in the same state and belongs to the same person; but as often as it is both changed and alienated, it should be understood as a sale rather than a hire.