We may infer, from a comparison of prices, that money is not more plentiful in China than it was in Europe three centuries ago; but what immense power is that empire possessed of, if we may judge by the civil and military list maintained by it! Polybius tells us that provisions were so cheap in Italy during his time that in some places the stated club​[16] at the inns was a _semis_ a head, little more than a farthing! Yet the Roman power had even then subdued the whole known world. About a century before that period the Carthaginian ambassador said, by way of raillery, that no people lived more sociably amongst themselves than the Romans, for that in every entertainment which, as foreign ministers, they received they still observed the same plate at every table. The absolute quantity of the precious metals is a matter of great indifference. There are only two circumstances of any importance—viz., their gradual increase and their thorough concoction and circulation through the state; and the influence of both these circumstances has been here explained.

In the following essay we shall see an instance of a like fallacy as that above mentioned, where a collateral effect is taken for a cause, and where a consequence is ascribed to the plenty of money; though it be really owing to a change in the manners and customs of the people.

Hume's Political Discourses — Part 41

[12] A private soldier in the Roman infantry had a denarius a day, somewhat less than eightpence. The Roman emperors had commonly 25 legions in pay, which, allowing 5000 men to a legion, makes 125,000. (Tacitus, _Ann._ lib. 4.) It is true there were also auxiliaries to the legions, but their numbers are uncertain as well as their pay. To consider only the legionaries, the pay of the private men could not exceed £1,600,000. Now, the Parliament in the last war commonly allowed for the fleet £2,500,000. We have therefore £900,000 over for the officers and other expenses of the Roman legions. There seem to have been but few officers in the Roman armies in comparison of what are employed in all our modern troops, except some Swiss corps. And these officers had very small pay: a centurion, for instance, only double a common soldier. And as the soldiers from their pay (Tacitus, _Ann._ lib. 1) bought their own clothes, arms, tents, and baggage, this must also diminish considerably the other charges of the army. So little expensive was that mighty Government, and so easy was its yoke over the world. And, indeed, this is the more natural conclusion from the foregoing calculations; for money, after the conquest of Egypt, seems to have been nearly in as great plenty at Rome as it is at present in the richest of the European kingdoms.

Hume's Political Discourses — Part 41