This is a suit for the infringement of Letters Patent, No. 962678, Claims 1 and 2, brought by the petitioner in the District Court of Maine, where the petitioner prevalid (23 F.(2d) 931), the Court acting partly in deference to the decision of the Circuit Court of Appeals for the Third Circuit in Miami Copper Co. v. Minerals Separation, Ltd., 244 F. 752. The decision of the District Court was reversed by the Circuit Court of Appeals for the First Circuit, 30 F.(2d) 67, and because of the conflict with the Third Circuit, a writ of certiorari was granted by this Court. 279 U.S. 832, 49 S.C.t. 481, 73 L. Ed. 982.
The claims are (1) for a 'process of concentrating ores which consists in mixing the powdered ore with water containing in solution a small quantity of a mineral frothing agent, agitating the mixture to form a froth and separating the froth,' and (2) the same as (1) except that it inserts the word 'organic' before 'mineral frothing agent.' The only defence that it is necessary to consider is that the disclosure is anticipated by the earlier patent, No. 835120, which has been before this Court in Minerals Separation Ltd., v. Hyde, 242 U.S. 261, 37 S.C.t. 82, 61 L. Ed. 286, and Minerals Separation, Ltd., v. Butte & Superior Mining Co., 250 U.S. 336, 39 S.C.t. 496, 63 L. Ed. 1019. It is enough to refer to those cases without repeating them. The process described in 835120 'consists in mixing the powdered ore with water, adding a small proportion of an oily liquid having a preferential affinity for metalliferous matter (amounting to a fraction of one per cent. on the ore), agitating the mixture until the oil coated mineral matter forms into a froth, and separating the froth from the remainder by flotation.' The specification describes the object as being to separate metalliferous matter, &c., from gangue by means of oils, fatty acids, 'or other substances which have a preferential affinity for metalliferous matter over gangue.' It refers to a previous patent to Cattermole by which a considerable amount of oil is used to form granules, and announces the discovery that if the proportion of oily substance is reduced to, say, a fraction of one per cent. on the ores, granulation ceases to take place, and on vigorous agitation the ore instead of sinking forms a froth on the surface that can be removed. The process is helped by the addition of a little acid, by warming and the fine pulverization of the pulp.
The petitioners, admitting that both patents are for processes, says that they are fundamentally different in their respective principles of action; that in the present patent, 962678, the mineral frothing agent is dissolved in the water and produces the metal bearing bubbles, no one knows exactly how, by 'modifying the water'; whereas in the earlier, 835120, oil is used which does not dissolve in the water but coats the particles of metal with a thin coating of oil, which it could not do if it were soluble, and thus shows its preferential affinity when shaken up with the metal pulp.