May we not infer from this account that the North of Italy was then much less peopled and worse cultivated than at present? How could these vast herds be fed in a country so thick of enclosures, so improved by agriculture, so divided by farms, so planted with vines and corn intermingled together? I must confess that Polybius’s relation has more the air of that economy which is to be met with in our American colonies than the management of a European country. We meet with a reflection in Aristotle’s​[90] _Ethics_ which seems to me unaccountable on any supposition, and by proving too much in favour of our present reasoning, may be thought really to prove nothing. That philosopher, treating of friendship, and observing that that relation ought neither to be contracted to the very few nor extended over a great multitude, illustrates his opinion by the following argument. “In like manner,” says he, “as a city cannot subsist if it either have so few inhabitants as ten, or so many as a hundred thousand, so is there a mediocrity required in the number of friends, and you destroy the essence of friendship by running into either extreme.” What! impossible that a city can contain a hundred thousand inhabitants! Had Aristotle never seen nor heard of a city which was near so populous? This, I must own, passes my comprehension. Pliny tells us that Seleucia, the seat of the Greek empire in the East, was reported to contain 600,000 people. Carthage is said by Strabo to have contained 700,000. The inhabitants of Pekin are not much more numerous. London, Paris, and Constantinople may admit of nearly the same computation; at least, the two latter cities do not exceed it. Rome, Alexandria, Antioch we have already spoke of. From the experience of past and present ages one might conjecture that there is a kind of impossibility that any city could ever rise much beyond this proportion. Whether the grandeur of a city be founded on commerce or on empire, there seems to be invincible obstacles which prevent its further progress. The seats of vast monarchies, by introducing extravagant luxury, irregular expense, idleness, dependence, and false ideas of rank and superiority, are improper for commerce. Extensive commerce checks itself by raising the price of all labour and commodities. When a great court engages the attendance of a numerous nobility possessed of overgrown fortunes, the middling gentry remain in their provincial towns, where they can make a figure on a moderate income. And if the dominions of a state arrive at an enormous size, there necessarily arise many capitals in the remoter provinces, whither all the inhabitants except a few courtiers repair for education, fortune, and amusement.​[91] London, by uniting extensive commerce and middling empire, has perhaps arrived at a greatness which no city will ever be able to exceed.