Each of these materials has, in each situation, a value which is the reflection of its power to appeal to choice.

Now, if to the commodity-use is added the money-use, this increases the demand for that good.

No new theory is required to explain the value of a commodity as it gradually acquires the added use of a medium of trade.

The money use is one that works no physical or visible change in goods except a slight unavoidable abrasion, and at any time a person receiving a piece of commodity money may retain it for its use-value, as food, ornament, tool, or weapon, or may retain it for a time and then spend it as money.

This case of value is no more difficult than that of anything else having two or more uses.
For example, cattle are used for milk, for meat, and as beasts of burden.