We have seen that every good is “in supply” if it can be divided into units, each of which is homogeneous with every other. Goods can be bought and sold only in terms of such units, and those goods which are indivisible and unique may be described as being in a supply of one unit only. Tangible commodities are generally traded in terms of units of weight, such as tons, pounds, ounces, grains, grams, etc. The money commodity is no exception to this rule. The most universally traded commodity in the community, it is bought and sold always in terms of units of its weight.