On the second point those farms are the most profitable which have opportunities in the vicinity for marketing what they raise and buying what they must consume: for there are many farms which must buy corn or wine or what ever else they lack, and not a few which have a surplus of these commodities for sale. So in the suburbs of a city it is fitting to cultivate gardens on a large scale, and to grow violets and roses and many other such things which a city consumes, while it would be folly to undertake this on a distant farm with no facilities for reaching the market. So, again, if there is nearby a town or a village or even the well furnished estate of a rich man where you can buy cheap what you require on the farm, and where you can trade your surplus of such things as props and poles and reeds, your farm will be more profitable than if you had to buy at a distance; nay, more profitable even than if you were able to produce all you require at home: because in this situation you can make annual arrangements with your neighbours to furnish on hire the services of physicians, fullers and blacksmiths to better advantage than if they were your own: for the death of a single such skilled slave wipes out the entire profit of a farm. In carrying on the operation of a vast estate, the rich can afford to provide such servants for every department of the work: for if towns and villages are far distant from the farm, they supply blacksmiths and all other necessary craftsmen and keep them on the place, in order to prevent the hands from leaving the farm and spending working days in going leisurely to and from the shop when they might more profitably be engaged on what should be done in the fields. So Saserna's book lays down the rule that "No one may leave the farm except the overseer, the butler, or such a one as the overseer sends on an errand. If any one disobeys this rule, he shall be punished for it, but if he disobeys a second time the overseer shall be punished." This rule may be better stated that no one should leave the farm without the approval of the overseer, and, without the consent of the master, not even the overseer, for more than a day at a time, but in no event more frequently than the business of the farm requires. On the third point, conveniences of transportation make a farm more profitable, and these are whether the roads are in such condition that wagons can use them smoothly, or whether there are rivers nearby which can be navigated. We know that each of these means of transportation is available to many farms.