D. In the case also of those raw materials which are objects of occupation, and never of real production, as, for instance, minerals, a progressive public economy, by altering the different elements of price in an opposite direction, may leave their price on the whole unchanged. Here, indeed, the discovery of new and especially of rich natural stores may exert an incalculable influence; but such “accidents” underlie the laws of human development only to the extent that those ages which are intellectually most active are those also which are most industrious and fortunate in the discovery of their natural resources.(810) Section CXXXIV. History Of The Prices Of The Chief Wants Of Life. (Continued.) E. The products of industry become cheaper and cheaper as economic culture advances; whereas, for instance, in England, towards the end of the middle ages, a single shirt was considered of importance enough to be made not unfrequently an object of testamentary bequest.(811) And, indeed, the price of industrial products sinks lower the more important the part played in their production by capital and the division of labor is as compared with the part played by the raw material.(812) On this account, in recent times, fine cloths have grown, relatively speaking, much cheaper than coarse ones.(813) Lead, which during the middle ages in England was much cheaper than iron, because of the difficulty of mining the latter, has become much dearer in our days.(814) Conversely, where raw material plays the most important part in manufactures, the price of the manufactured article may increase with an advance in civilization. Hence, articles made of wood are procured at the cheapest rates in mountainous countries, where the division of labor is not carried very far, but where the raw material is cheap.(815) F. But the price of commodities decreases, especially in the higher stages of civilization, to the extent that it is dependent on commerce.(816) Here capital and human labor almost exclusively are effective, and the modern improvements of communication, legal security and competition are especially striking.(817)