5. The men [of the country], being well acquainted with the nature of these places, and that the estuaries would very well answer the same purpose as rivers, founded cities and other settlements along them the same as along rivers. Of this number are Asta, Nebrissa,[1048] Onoba,[1049] Ossonoba, Mænoba,[CASAUB. 143] besides many others. The canals which have been cut in various directions are also found useful in the traffic which is carried on between place and place, both amongst the people themselves and with foreigners. The conflux of water at the flood-tides is also valuable, as rendering navigable the isthmuses which separate the different pieces of water, thus making it possible to ferry over from the rivers into the estuaries, and from the estuaries into the rivers. Their trade is wholly carried on with Italy and Rome. The navigation is excellent as far as the Pillars, (excepting perhaps some little difficulties at the Strait,) and equally so on the Mediterranean, where the voyages are very calm, especially to those who keep the high seas. This is a great advantage to merchant-vessels. The winds on the high seas blow regularly; and peace reigns there now, the pirates having been put down, so that in every respect the voyage is facile. Posidonius tells us he observed the singular phenomenon in his journey from Iberia,[1050] that in this sea, as far as the Gulf of Sardinia, the south-east[1051] winds blow periodically. And on this account he strove in vain for three whole months to reach Italy, being driven about by the winds against the Gymnesian islands,[1052] Sardinia, and the opposite coasts of Libya.