delivered tbe opinion of tbe Court:

Tbis appeal is from a decision of tbe Commissioner of Patents rejecting as unpatentable certain claims for electric lamps of tbe character known as vapor lamps, or vapor arc lamps.

Tbe rejection was based upon a British patent to appellants of 1903, which concededly contained tbe subject-matter of tbe appealed claims. A provisional application for tbe British patent was filed more than one year prior to tbe date of filing tbe present application, which, it was held, renders tbe British patent a bar to tbe granting of a patent on tbe appealed claims. U. S. Rev. Stat. sec. 4887, Comp. Stat. 1913, sec. 9431.

But it is argued that tbe completed specification of tbe British patent was filed less than a year before the present application, and that tbe provisional application did not disclose tbe subject-matter of tbe appealed claims. We have held, however, that tbe bar of tbe statute begins to run from tbe date of tbe filing of a foreign provisional specification which ripens into a patent disclosing tbe subject-matter of tbe claim upon which a domestic patent is sought. Re Swinburne, 19 App. D. C. 565.

It is also insisted that tbe appealed claims are closely related to claims which have been allowed in a patent to one Euch, whose application was junior to that of appellants. When tbe Commissioner rejected appellants’ claims as unpatentable, appellants requested a reference of tbe case back to tbe Examiner, •with instructions to declare an interference with Buck. Erom tbe refusal of tbe Commissioner to grant tbis request, error is here assigned. To recognize tbis as a proper ground of appeal, and sustain tbe contention of appellants, would be equivalent to compelling tbe declaration of an interference in tbe Patent Office. Tbis we have held not to be within our appellate jurisdiction. In tbe very early case of Westinghouse v. Duncan, 2 *427App. D. C. 131, this court, through Chief Justice Alvey, held that from “the mere refusal of the Commissioner to direct an investigation and determination of the Examiners as to an alleged interference of an application for a patent with any pending application, or with any unexpired patent, is but a preliminary opinion, as to the propriety of such examination, formed in the exercise of a sound discretion; and as the foundation for the exercise of such discretion, the Commissioner is at liberty to obtain extrinsic information as to the interfering claims. Potter v. Dixon, 5 Blatchf. 160, Fed. Cas. No. 11,325. From this preliminary opinion of the Commissioner, no appeal lies to this court.” This rule as to interlocutory orders and rulings on mere matters of procedure has been consistently adhered to. Allen v. United States, 26 App. D. C. 8; Union Distilling Co. v. Schneider, 29 App. D. C. 1; Re Fullagar, 32 App. D. C. 222; Cosper v. Gold, 34 App. D. C. 194; Universal Motor Truck Co. v. Universal Motor Co. 41 App. D. C. 261.

The decision of the Commissioner of Patents is affirmed, and the clerk is directed to certify these proceedings as by law required. Affirmed.