XVII[17arg] The meaning of the expression found in the old praetorian edicts: “those who have undertaken public contracts for clearing the rivers of nets.”
As I chanced to be sitting in the library of Trajan's temple, 1 looking for something else, the edicts of the early praetors fell into my hands, and I thought it worth while to read and become acquainted with them. Then I found this, written in one of the earlier edicts: “If anyone of those who have taken public contracts for clearing the rivers of nets shall be brought before me, and shall be accused of not having done that which by the terms of his contract he was bound to do.” Thereupon the question arose what “clearing of nets” meant. Then a friend of mine who was sitting with us said that he had read in the seventh book of Gavius On the Origin of Words 2 that those trees which either projected from the banks of rivers, or were found in their beds, were called retae, and that they got their name from nets, because they impeded the course of ships and, so to speak, netted them. Therefore he thought that the custom was to farm [p. 343] out the rivers to be “cleaned of nets,” that is to say, cleaned out, in order that vessels meeting such branches might suffer neither delay nor danger.