Value is the common quality of wealth. Wealth in most of its aspects is highly heterogeneous: hay and milk, iron and corn-land, cows and calico, human services and gold watches, dollars and doughnuts, pig-pens and pearls--all these things, diverse though they be in their physical attributes, have one quality in common: Economic Value.[4] By virtue of this common or generic quality, it is possible to add wealth together to get a sum, to compare items of wealth with one another, to see which is greater, to get ratios of exchange between items of wealth, to speak of one item of wealth, say a crop of wheat, as being a percentage of another, say the land which produced it, etc. This common quality, value, is also a _quantity_. It belongs to that class of qualities which can be greater or less, can mount or descend a scale, without ceasing to be the same quality,--like heat or weight or length. Such qualities are _quantities_. There is nothing novel in the statement that a quality is also a quantity. It is implied in every day speech. We say that a man is tall, or heavy, or that the room is hot--qualitative statements; or we may say exactly how tall, or how heavy, or how hot--quantitative statements. The distinction between qualitative analysis and quantitative analysis in chemistry implies the same idea. Thus we may speak of a piece of wealth as having a definite quantity of value, or say that the value of the piece of wealth is a definite quantity. We may then work out mathematical relations among the different quantities of value, sums, ratios, percentages, etc. Ratios of Exchange are ratios between two quantities of value, the values of the units of the two kinds of wealth exchanged.[5] A good many economists, particularly in their chapters on definition, have defined value as a ratio of exchange. This is inaccurate. The ratio of exchange presupposes _two_ values, which are the terms of the ratio. The ratio is not between milk and wheat in all their attributes. It is between milk and wheat with respect to one particular attribute. Compare them on the basis of weight, or cubic contents, and you would get ratios quite different from the ratio which actually is the ratio of exchange. The ratio is between their values. [Illustration: Ratio of Exchange Milk ------------------------- Wheat \ / \ / \ Value Value / \ / \ / \ / \ / Social Mind ]