1. The poor ores may be smelted with profit, without putting the
companies to any risk or expense in the erection of new works; 2, by the
mixture of many different ores, the smelting and metallic product become
more easy and abundant; 3, the train of the operations is conducted with
all the lights and resources of science; and 4, the amount of metal
brought into the market is not subject to such fluctuations as might
prove injurious to their sale.