§ 15. The evils of trade depression, or excessive growth of the forms of capital beyond the limits imposed by consumption, are traced in large measure directly, but also indirectly, to the free play of individual interests in the development of machine-production. The essential irregularities of invention, the fluctuations of public taste, the artificial restrictions of markets, all enable individual capitalists to gain at the public expense. The added interests of its individual members do not make the interest of the community. All these modes of conflict between the individual and the public interest derive force from the complexity of modern capitalist production. In fastening upon the uncontrolled growth of machinery the chief responsibility for that depression of trade which is derived from an attempt to devote too large a proportion of the productive power of the community to forms of "saving," two points should be clearly understood. In the first place, it is the forms of capital and not real capital which are produced in excess. If there are 500 spinning-mills in Lancashire where 300 would suffice, the destruction of 200 mills would no whit diminish the amount of real capital. If 200 mills were burnt down, though the individual owners would sustain a loss, that loss, estimated in money, would be compensated by a money rise in the value of the other mills. The quantity of real capital in cotton-spinning is dependent upon the demand for the use of such forms of capital--that is to say, upon the consumption of cotton goods. If 300 mills are sufficient to do the work of supplying yarn to meet the demand of all manufacturers, the value of 500 mills is no greater than of 300; assuming that the 500 mills equally distributed the trade, it would simply mean that the real capital was thinly spread over 500 mills, which could only work a little over half-time without producing a glut of goods, instead of being concentrated upon 300 mills fully occupied. Turning once more to the diagram, [Illustration] _f_ (the current rate of consumption) determines the quantity of real productive power of capital that can be effectively employed at each point, _a_, _b_, _c_, _d_, _e_. The condition of the arts of industry, including the rates of wages and other conditions of the labour market, determines how many forms of capital (mills, warehouses, ironworks, raw material, etc.) at any given time are socially requisite to embody this capital. But though _f_ has an economic power to force into existence the requisite minimum of these forms of capital, it has no power to prevent the pressure of individual interests from exceeding that minimum and planting at _a_, _b_, _c_, _d_, _e_ more forms of capital than are required.