If we turn to investigate the several departments of industry in the more highly-evolved communities, where statistics yield more accurate information, we have most distinct evidence that so far as the world-market is concerned, the fluctuations are far more extreme in the industries to which machine-production and high organisation have been applied. An investigation of changes of wholesale prices indicates that the most rapid and extreme fluctuations are found in the prices of textile and mineral materials which form the foundation of our leading manufactures. A comparison of the price changes of food as a whole, and of corn prices with textiles and minerals, shows that especially during the last thirty years the fluctuations of the latter have been much more rapid and pronounced. (See following diagrams.) [Illustration: COURSE OF AVERAGE PRICES OF GENERAL COMMODITIES.] [Illustration: CORN PRICES.] § 5. It ought to be clearly understood that the real congestion with which we are concerned, the over-supply, does not chiefly consist of goods in their raw or finished state passing through the machine on their way to the consumer. The economic diagnosis is sometimes confused upon this point, speaking of the increased productive power of machinery as if it continued to pour forth an unchecked flood of goods in excess of possible consumption. This shows a deep misunderstanding of the malady. Only in its early stages does it take this form. When in any trade the producing power of machinery is in excess of the demand at a remunerative price, the series of processes through which the raw material passes on its way to the consumer soon become congested with an over-supply. This, however, need not be very large, nor does it long continue to grow. So long as the production of these excessive wares continues, though we have a growing glut of them, the worst features of industrial disease do not appear; profits are low, perhaps business is carried on at a loss, but factories, workshops, mines, railways, etc., are in active operation; wages may be reduced, but there is plenty of employment. It is when this congestion of goods has clogged the wheels of the industrial machine, retarded the rate of production, when the weaker manufacturers can no longer get credit at the bank, can no longer meet their engagements, and collapse, when the stronger firms are forced to close some of their mills, to shut down the less productive mines, to work short hours, to economise in every form of labour, that depression of trade assumes its more enduring and injurious shape. The condition now is not that of an increasing glut of goods; the existing glut continues to block the avenues of commerce and to check further production, but it does not represent the real burden of over-supply. The true excess now shows itself in the shape of idle machinery, closed factories, unworked mines, unused ships and railway trucks.