delivered the opinion of the Court:
The proceeding in this case began with an application by Herman Trasch, filed November 13, 1899, for a patent for a process and apparatus for removing incrustation of calcium sulphate from brine-heating surfaces.
The application concludes with six claims, the first three of which are for the process, and the last three for a particular apparatus to be used in the application of the process.
The primary examiner, on December 16, 1899, notified the applicant that his specifications and claims presented two different subjects of invention, namely, process and apparatus, and, calling his attention to Hule 41 requiring division in such cases, stated that “'division on this line must be made before action upon the merits can be given.”
Hule 41 reads as follows:
“ 41. Two or more independent inventions cannot be claimed in one application; but where several distinct inventions are dependent upon each other and mutually contribute to produce a single result they may be claimed in one application.
“ Claims for a machine and its product must be presented in separate applications.
“ Claims for a machine and the process in the performance of which the machine is used must be presented in separate applications.
“ Claims for a process and its product may be presented in the same application.”
After hearing argument on behalf of the appellant, the examiner repeated the order for division, and notified the applicant that there was no appeal because there had been no *300rejection of his application. He therefore declined to transmit the case to the examiners-in-chief as appealed from his decision, and called applicant’s attention to his right of petition to the Commissioner of Patents under Rule 145, which authorizes the review by the Commissioner of any repeated ruling of an examiner — “ which does not involve the merits of the invention claimed, or the rejection of a claim.”
On December 19, 1901, applicant presented a petition to the Commissioner in which he recited the proceedings in the Office and the rulings of the examiner and prayed relief.
On January 23, 1902, the Commissioner rendered the following decision upon this petition:
“ This is a petition from the action of the primary examiner requiring division in the above-entitled case and refusing to forward to the examiners-in-chief an appeal which has been filed.
“ The application includes claims to a process and claims to an apparatus, and therefore the examiner properly required division and refused to act upon the merits of the claims until that requirement was complied with. The petitioner regarded this as a refusal of a patent to him and filed a request for reconsideration, which he calls a persistence in his claim, under section 4903 of the Revised Statutes, and upon a repetition of the requirement for division filed an appeal to the examiners-in-chief.
“A requirement for division is not an action upon the merits of the application, but is a mere matter of form, and therefore a party has no right to appeal to the examiners-in-chief from such a requirement. It is not a refusal of a patent or patents upon the alleged invention or inventions, but is a ruling that the application therefor has not been made in proper form. The requirement of division may be and often is made where all of the claims are admitted to be patentable. The objection is to the way in which the matter is presented and not to the matter itself. The examiner was right in refusing to forward the appeal. The petition is denied.”
*301From that decision the appeal has been prosecuted. On behalf of the Commissioner, a motion has been entered to dismiss for want of jurisdiction in this court to entertain the appeal.
The motion' to dismiss the appeal must be granted. The right to appeal to this court- from a decision of the Commissioner of Patents is limited to two classes of cases: first, where an application for patent has been finally denied; and, second, where, in an interference proceeding, there has been a final determination of the question of priority of invention between adverse claimants. R. S., Secs. 4911, 4912, 4913, 4914; R. S. D. C., Sec. 780; act creating Court of Appeals, D. C.: approved February 9, 1893, Sec. 9.
There has been no denial of the application in this case. Its merits have not been considered. The examiner has declined to pass upon the application or to consider the allowance of the claims, because, in his opinion, he is bound by the terms of Eule 41 to demand a division of the application; that is to say, a separate application each for the process and for the apparatus embraced in the claims of the pending application. On petition against this ruling, the examiner has been sustained by the Commissioner. It is a mere interlocutory order from which, in either class of cases, there can be no appeal, for reasons which have been heretofore stated, and need not be repeated. Westinghouse v. Duncan, 2 App. D. C. 131, 134. Moreover, upon appeal from a final decision on the merits, it has been held that “ the rulings on questions of mere practice in the Patent Office will not be reviewed in this court, unless it appear that there has been an abuse in the exercise of discretion, and that substantial rights have been thereby affected or denied.” In re Marschutz, 13 App. D. C. 228, 236; In re Neill, 11 App. D. C. 584, 588.
The contention of the appellant is, that Eule 41 is inconsistent -with the statutes providing for the grant of letters patent, and, therefore, beyond the power of the Commissioner of Patents to enact; wherefore its enforcement in this case has worked a practical denial of the application. That *302such is the substantial or necessary result of the ruling we cannot agree. We do not mean to say that there may not be a way in which the power to enact Rule 41 might be brought in question as necessarily involving the denial of a substantial right under the law.
If there be such a way, however, it has not been pursued in this proceeding. Whether the power exists presents a question of great importance, both to applicants for patents and to the Government, if for no other reason than the doubling of fees which must necessarily result from its strict enforcement. Nevertheless, the question is one of practice, and to be determined by this court must come up, not on appeal from an interlocutory order for the enforcement of the rule, but as necessarily involved in a final decision of the Commissioner rejecting an application for a patent, as intimated in the cases last above cited.
Without intending to intimate any view in respect of the authority for, or the expediency of the purpose of, the enactment of Rule 41 by the Commissioner, it may be of some interest to briefly state its history.
The rule, as it now reads, was adopted by Mr. Commissioner Duell July 18, 1899. The change consisted in adding to the rule as it then read, the three last paragraphs which require separate applications for claims for a machine and its product, for a machine and the process in the performance of which it is used, and a single application for a process and its product.
Under the general terms of the old Rule 41, the practice of the Patent Office had varied from time to time under different administrations, and fallen into some confusion as claimed by Mr. Commissioner Duell in a decision wherein he set forth the reasons inducing him to amePd the rule in the particulars noted. Ex parte Boucher, 88 O. G. 545; C. D., 1899, p. 133, decided July 11, 1899.
In that opinion he referred to the decision of the Supreme Court of the United States which recognized the general discretion committed to the head of the Patent Office in the matter of the division of applications (Bennet v. Fowler, 8 *303Wall. 445), as well as to the manner in which that discretion had been exercised by many preceding Commissioners.
In a later case he considered the subject again, at length, in justifying the amendment that had been made. Ex parte Frasch, 91 O. G. 459; C. D., 1900, p. 50.
In that opinion he cited several decisions of the Supreme Court of the "United States, as sustaining his view that a process and an apparatus to be used in its application, are separate and distinct inventions.
Without pursuing the subject further, the appeal will be dismissed without prejudice, for the reasons given; and this decision and the proceedings herein will be certified to the Commissioner of Patents as required by law. It is so ordered.