delivered the opinion of the Court:
Because of the view we take on a vital point in this ease, we deem it unnecessary to consider various preliminary questions, and shall assume, without deciding, that in a proper case jurisdiction to issue a writ of certiorari to the Patent Office exists. In many jurisdictions the common-law writ of certiorari has been supplanted by a statutory writ of review, but that has not been done- here. The function and scope of the writ in the District of Columbia were carefully and clearly stated by Mr. *23Chief Justice Shepard in Degge v. Hitchcock, 35 App. D. C. 218. In the case of Re Tampa, Suburban R. Co. 168 U. S. 583, 42 L. ed. 589, 18 Sup. Ct. Rep. 177, the general rule governing the issuance of the writ is stated to be that the “writ will be granted or denied, in the sound discretion of the court, on special cause or ground shown; and will be refused where there is a plain and equally adequate remedy by appeal or otherwise.”
The theory upon which the writ is sometimes issued to test the question of jurisdiction, notwithstanding a remedy by appeal or writ of error exists, is that when the tribunal whose action is sought to be reviewed has proceeded without jurisdiction, and that fact appears upon the face of the record, the issuance of the writ affords a more efficient remedy if it summarily ends an expensive and protracted litigation. Harris v. Barber, 129 U. S. 366, 32 L. ed. 697, 9 Sup. Ct. Rep. 314; Gaither v. Watkins, 66 Md. 576, 8 Atl. 464. If, however, there is another adequate remedy available, the writ will not be granted. Presbyterian Church v. District of Columbia, 34 App. D. C. 600; Mark v. District of Columbia, 35 App. D. C. 574. Nor will the writ be granted unless to accomplish substantial justice. District of Columbia v. Brooke, 29 App. D. C. 563.
Without expressing any opinion as to whether Field was guilty of laches in filing his petition for the writ, we proceed to inquire whether, when Field prayed the issuance of the writ of certiorari, an equally adequate remedy by appeal was open to him.
In the act of Feb. 9, 1893 (27 Stat. at L. 434, chap. 74, U. S. Comp. Stat. 1901, p. 3391), creating this court, the jurisdiction of the general term of the supreme court of the District over appeals from the Commissioner of Patents was transferred to this court, and it was further provided that “any party aggrieved by a decision of the Commissioner of Patents in an interference case may appeal therefrom to said court of appeals.”
When, therefore, judgment on the record was entered in favor of Colman and against Field by the Examiner of Interferences, a right of appeal through the Board of Examiners in Chief and the Commissioner to this court existed. Judgment would have *24been entered as a matter, of course by the Examiners in Chief and the Commissioner in turn, and the appeal to this court would not have involved, as alleged by Eield in his petition for the writ, “a long, protracted, and inconclusive course of proceedings.” Had he pursued the course prescribed by the statute, instead of resorting to this extraordinary remedy, he would have reached this court — the court especially clothed by law with jurisdiction over such appeals — quite as soon as he now has; and inasmuch as the judgment appealed from would have been a final judgment, every question raised by his petition for certiorari could have been raised by appeal. Moreover, it is quite evident that even if we should affirm this judgment of the trial court, the real issue involved in the interference case, namely the question of priority of invention,, would still be undetermined. It would still be necessary for the various tribunals of the Patent Office to consider and to determine that question, and from their ultimate judgment an appeal would lie to this court. This situation demonstrates the futility of interference, by a court having no general jurisdiction or con-' trol over the affairs of the Patent Office, with the regular and orderly trial of cases in that office, when the very questions raised in that court may be quite as expeditiously raised by appeal. Such a practice, if established, would still further complicate rather than simplify patent practice, and we feel sure, add to the burdens of applicants, and delay instead of expedíate final action.
But, it is insisted, the discretion exercised by the trial court is not reviewable, and therefore its judgment will not be disturbed by an appellate tribunal except for errors in the determination of the questions arising upon the record. This court, in sec. 7 of the act of its creation (27 Stat. at L. 434, chap. 74), was expressly given jurisdiction to “affirm, reverse, or modify,” on appeal, any final order, judgment or decree of the supreme court of the District. This provision surely clothes this court with authority to inquire whether the trial court has exercised its discretion in accordance with established rules and prece-: dents governing the exercise of such discretion. .The court so *25ruled in Trustees of Schools v. School Directors, 88 Ill. 100, an opposite case. The discretionary power exercised by the trial court in passing upon an application for the writ being neither absolute nor arbitrary, the general rule, even in the absence of statutory provision, is that the appellate court will inquire whether there has been a departure from settled principles in the granting or withholding of the writ, to the injury of one of the parties. Board of Supervisors v. Magoon, 109 Ill. 142; McDowell v. Keller, 1 Heisk. 449; Welch v. County Ct. 29 W. Va. 63, 1 S. E. 337. It has been held, notably by the courts of New York, that except for a gross abuse of discretion the appellate court will not question the discretionary power of the trial court in granting or withholding the writ. We think, however, the better rule to be, as above indicated, that the appellate' court, except in a plain case, will inquire whether there was a sound exercise of discretion by the trial court. We think that when it clearly appears, as in this case, that there was an equally ef-ficient remedy by appeal open to the petitioner for the writ, it necessarily follows that there was lacking a fundamental requisite for the award of this extraordinary remedy, and that it therefore becomes the duty of the appellate court to refer the parties to the mode of redress prescribed by statute. We are convinced in this case that had the learned trial justice been properly enlightened as to the complicated practice in the Patent Office and the results that would inevitably flow from the granting of this writ, he would have withheld it. The statute has conferred jurisdiction upon this court to hear and determine appeals from the Patent Office. The only excuse, therefore, for invoking this common-law remedy is that relief by appeal will be less efficient. We are fully convinced that an appeal will afford fully as speedy and adequate redress as will be accomplished by certiorari. If proceedings in the Patent Office are to be interrupted by certiorari when there is an equally adequate remedy by appeal, it is clear that an additional tribunal not contemplated by the statute, namely, the supreme court of the District, will be interposed between the tribunals of the Patent Office and this court. In other words, instead of appeals *26coming direct to this court, an aggrieved person, by resorting to the writ of certiorari, will be enabled to prolong the contest by first taking the case to the supreme court. If such a practice should obtain, appeals in every instance would probably be prosecuted from that court to this, as otherwise when parties were sent back to the Patent Offi.ce they might find some important, if not controlling, question finally settled in the certiorari proceeding by a court having no general jurisdiction over questions arising in the Patent Office.
It appearing that an equally efficient remedy by appeal was open to appellee when he filed his petition for the writ of certiorari, the trial court should have dismissed his petition. The judgment will'therefore be revised, with costs, and the cause remanded for further proceedings. Reversed.