Plaintiff charged defendant with the infringement of United States patent No. 1,825,736 to Klein and Szegvari, and United States patent No. 1,996,051 to Twiss. The first patent was issued October 6, 1931, on an application filed May 29, 1926. The second patent was issued April 2, 1935, on an application filed February 19, 1931. Both patents are owned by the plaintiff. Claims 1, 16, 18 and 19 of the first patent, and claims 2, 4, 17, 18, 28 and 29 of the second patent were relied upon. The defenses were invalidity and non-infringement. The court found that all the claims relied upon in both patents were valid, and that all such claims, except claim 19 of the first patent, were infringed by the defendants device, referred to as its "regular process"; and that all claims relied upon, except claim 4 of the second patent, were infringed by defendants device referred to as its "developer process." The District Court made special findings of fact and rendered its conclusions of law thereon. A decree was accordingly entered in favor of the plaintiff, and from that decree this appeal is prosecuted.