delivered the opinion of the Court:

This appeal by Harry M. Pope is from a decision of the Commissioner of Patents disallowing six claims, of which the following are sufficiently representative:

“1. An internal combustion engine, a generator of continuously maintained periodic alternating current, a fixed igniting device for the charge in said engine in circuit with said generator, and means for isochronizing the instant of attainment of a selected electro-motive force and a predetermined piston position of the engine.”

“3. An internal combusion engine, a generator of continuously maintained periodic alternating current, a fixed igniting device for the charge in said engine in circuit with said generator, means for isochronizing the instant of attainment of maximum electro-motive force and a predetermined piston position of the engine, and means for augmenting said electromotive force.”

“5. An internal combusion engine, a generator of continuously maintained period alternating current, a fixed igniting device for the charge in said engine in circuit with said generator, means for operating said generator at a speed bearing a constant ratio to the speed of said engine, and means for changing the relation of the wave peak of said current with respect to a predetermined piston position.”

The tribunals' of the Patent Office have very carefully and *429very satisfactorily stated the reasons for the disallowance of these claims, and we do not deem it necessary to restate them. Before the Commisioner, as here, the rule of “reasonable doubt” was invoked in behalf of the applicant. The Commissioner said: “It is quite a common practice of the office to resolve any doubt in favor of an applicant for patent, but there is no rule of law compelling this, and though doubtless the practice works well in many cases, a universal application of it is of questionable wisdom.” After stating that the present application was filed May 10, 1899, that during the first fourteen years its prosecution was prolonged by the applicant to the fullest extent permissible under the statute, and that the device has gone into very wide use, the Commissioner concluded that it would be unreasonable to resolve in favor of the applicant any doubt that might exist “on the question whether the production of the combination claimed involved invention at the time of the filing of the application.” While it does not appear that the Commissioner was of the opinion that a doubt did exist, the applicant challenges this declaration of policy.

Though it is true that a patent may not be withheld because of delay authorized by the statute, we agree with the Commissioner that an applicant who has prolonged his application for a period of years, knowing that the device covered thereby has gone into public use, is not in a position to demand more than is strictly due him. In such a situation, the Commissioner would be fully justified in reversing the ordinary rule by resolving doubts against the applicant. The statute allowing the applicant a certain time within which to respond to the action of the Patent Office was not designed to permit him unduly to prolong his application. It is inconceivable that so great a delay as attended the present application could have resulted other than from design.

The decision is affirmed.

Affirmed.