In patent law, either a trial of an uncompleted mechanical structure to ascertain what changes or additions may be necessary to make it accomplish the design of the projector, or a trial of a completed machine to test or illustrate its practical efficiency. In the former case, the inventor’s efforts, being incomplete, if they are then abandoned, will have no effect upon the right of a subsequent inventor; but if the experiment proves the capacity of the machine to effect what its inventor proposed, the law assigns to him the merit of having produced a complete invention. Northwestern Fire Extinguisher Co. v. Philadelphia f ire Extinguisher Co., 10 Phila. 227, 18 Fed. Cas. 394.