As shown above, there are in the United States a few very large refineries whose ownership is in few hands. If these refineries control the sale of all the production of copper several objectionable features develop. The few sales agencies handle so much copper that there is a tendency to co-operate with representatives of foreign consumers who can buy in large quantities, and it is not difficult to manipulate the market temporarily, in disregard of actual conditions of demand and supply. Thus the entire output of copper, one of our great natural resources, is placed in the hands of groups who, while interested in mining, are more interested in refining. The best interests of the industry are more nearly those of the miner than of the refiner. Therefore, the most positive dislodgment of former German control of copper through selling will come from the breaking up of the former system and transferring each unit of that system to other hands; rather than transferring the old units in block to non-German hands. Sales of American copper should be handled by a large number of separate agencies actively competing for the domestic market; this is essential in the interests of the consumer and of the country. But export copper business should be handled through one agency or association representing all the sales agencies, as is now legal, and this should be done in the interests of the producer and of the country. =Reserves of United States Copper Mines.=--The developed reserves of United States copper deposits are fully equal, in proportion to output, to such reserves in foreign copper deposits. This insures the fact that for the next ten years, at least, the copper production of the United States will maintain its present relative dominance over all foreign countries. A large proportion of all copper deposits are of such a deep-seated character that at no time can large reserves be positively developed, even when they exist. On the other hand, all over the world the mines with large known reserves are horizontal deposits, lying near the surface, because only in such occurrences is it possible to block out easily and cheaply big tonnages of ore. There are in the United States six very important deposits of this type, the so-called “porphyries.” These are: TABLE 40.--“PORPHYRY” COPPER MINES IN THE UNITED STATES