§ 3. The causes of the existence of these groups in the United States to-day. Inequality of natural ability; inequality of opportunity; artificial barriers. All these contradictory to assumptions behind theory of general rate of wages.

§ 4. Trade unions another factor in the formation of relatively separate groups. Indirect effects in opposite direction.

§ 5. Each of these groups has a relatively independent economic career. There are a series of wage levels, all of which are governed to a considerable extent by the same forces.

§ 6. The way in which the relative plenty or scarcity of each kind or group of labor affects its wages. Other forces play a part also.

§ 7. The nature of wage "differentials."

Chapter V—Wages and Price Movements [87]

§ 1. The transactions of distribution arranged in terms of money. How does this affect the outcome of distribution as regards wages?

§ 2. The characteristics of price movements.

§ 3. The direct and indirect effects of upward price movements upon the distribution of the product.

§ 4. The direct and indirect effects of falling price movements upon the distribution of the product.