If we take the case of any modern country, the amount of its income at any given time depends for its sustentation on machines already in existence; and its increase is dependent on the gradual supersession of these by new ones yet more efficient. But the efficiency of the former would soon begin to decrease, and would ultimately disappear altogether, unless they were constantly repaired and their lost substance was renewed; while the latter would never exist unless there were men to make them. Hence, under modern conditions, in any prosperous and progressive country, a large portion of what is called the manufacturing class is always engaged, not in producing articles of consumption, comfort, or luxury, but in repairing and renewing the machines by which such articles are at present multiplied, or else in constructing new machines which shall supplement or replace the old. Thus, in Great Britain, towards the close of the nineteenth century, these makers and repairers of machinery were, with the exception of coal-miners, the industrial body whose proportional increase was greatest. In the modern world the spending of capital as income is a process which, in proportion as it became general, would accomplish itself by affecting the position of men like these. It would consist of a withdrawal of men who are at present occupied in maintaining existing machines, or else in constructing new ones from their anvils, hammers, files, lathes, and furnaces, and making them dance instead. This withdrawal would, in proportion as it became general, render the construction of new machines impossible, and would leave the efficiency of those now in use to exhaust itself.