They will.

Not to mention the importers and exporters, who are called merchants?

Yes.

Then we shall want merchants?

We shall.

And if merchandise is to be carried over the sea, skilful [B]sailors will also be needed, and in considerable numbers?

Yes, in considerable numbers.

Then, again, within the city, how will they exchange their 52 productions? To secure such an exchange was, as you will remember, one of our principal objects when we formed them into a society and constituted a State.

Clearly they will buy and sell.

Then they will need a market-place, and a money-token for purposes of exchange.