Dickinson invention, the cancelation does not seem to us important or to require a narrowing of Dickinson's claim for the described and indispensable cooperation of three or more pins to produce that movement.
The Court of Appeals bases something of its conclusion in this case on the alleged inoperativeness of the Dickinson machine. As to this, we find no reason in the record for disturbing the finding of the District Judge, with the working model and the witnesses before him, supported as he is by the finding of the Patent Office and the District Court of Appeals on extended evidence on this very point before them. It is not necessary, in order to sustain a generic patent, to show that the device is a commercial success. The machine patented may be imperfect in its operation; but if it embodies the generic principle, and works, that is, if it actually and mechanically performs, though only in a crude way, the important function by which it makes the substantial change claimed for it in the art, it is enough. Telephone Cases, 126 U. S. 1, 535; Mergenthaler Linotype Co. v. Press Publishing Co., 57 Fed. 502, 505.
The Patent Office treated the Dickinson invention as a primary or generic one. So did the Court of Appeals of the District of Columbia (25 App. D. C. 316), Judge Rose of the District Court of Maryland (Hildreth v. Loner & Suter Co., 208 Fed. 1005), and the Circuit Court of Appeals of the Fourth Circuit (Lauter & Suter Co. v. Hildreth, 219 Fed. 753). In this view, after a consideration of the record, and for the reasons stated, we concur. The history of the art shows that Dickinson took the important but long delayed and therefore not obvious step from the pulling of candy by two hands guided by a human mind and will to the performance of the same function by machine. The ultimate effect of this step with the mechanical or patentable improvements of his device was to make candy pulling more sanitary, to re-
