Colt, J.
In the case of the complainant company against the Elliott Door-Check Company (26 Fed. Rep. 320) this court sustained the validity of the second claim of the Richards patent, No. 144,926, for an improvement in door-springs. The claim was as follows: “The grooved screw, I, for adjusting the vent, in combination with the packing, H, piston, G, tube, D, and coiled spring, F, or equivalent, substantially as herein shown and described.-” In the opinion in the Elliott Case the court said: “We must also bear in mind that Richards was the first to organize a machine to check the motion of a door before it closes, and thus prevent slamming; and that, therefore, his patent is entitled to a broad construction.” In the present case I am referred to prior devices which were not before me in the Elliott Case. An examination of these devices has led me to the conclusion that I may have given too broad a construction *693to the Richards patent in the other suit. Indeed, I may say that the Corliss air dash-pot, and the exhibit Colt’s armory door-check, now for the first time introduced as evidence, have raised a doubt in my mind as to the soundness of the construction put upon the second claim of the Richards patent in the Elliott suit. From a working exhibit introduced by the defendants it would seem to make little or no difference so far as checking the motion of the door before slamming, whether the adjustable screw is placed at the side or bottom of the cylinder, provided the piston does not fit- too closely the bore of the cylinder. In other words, I am not clear in my own mind that there is not found in the Corliss dash-pot the substance of what is described in the second claim of the Richards patent. Further, in the exhibit Colt’s armory door-check it is admitted that the device consists of a cylinder, a piston, or equivalent, an adjustable vent, a weight, and a valve, which permits the air to enter the cylinder when the weight is raised by the opening of the door. If we substitute a spring lor the weight, the combination of devices here shown comes close to those found in the second claim of Richards’ patent. For the purpose of deciding this motion I am not called upon to critically compare the Richards device with the Corliss dash-pot or the Colt door-check. It is sufficient for me to say at this time that, after hearing the arguments of counsel, and upon a careful examination of the evidence and exhibits, a doubt is cast upon my mind whether, in view of the prior state of the art, the defendants infringe the second claim of the Richards patent. It is my duty, therefore, to deny this motion, and to postpone the determination of the questions now raised to final hearing. Motion denied.