delivered the opinion of the Court:

This is an interference proceeding between two independent inventors claiming priority of invention of a machine for slitting metal preparatory to its expansion.

Louis E. Curtis, the appellee, filed this application September 23, 1901. George A. Turnbull, the appellant, filed September 28, 1903, continuing a former application filed February 15, 1902.

The declaration of interference between these applications recites the following issue in five counts:

“1. In a machine of the class described, a plurality of pairs of cutting rolls and coacting, independently removable means on each pair of cutting rolls adapted to slit a sheet of metal into a'plurality of relatively short slits, the knives on each pair of said rolls forming slits alternating with those formed by the knives on the other pair.

“2. In a machine of the class described, the combination, with a frame, of a plurality of pairs of coacting rolls journalled thereon, means arranged on said rolls equidistant apart and adapted to cut a sheet of metal into a plurality of short slits arranged staggering with each other and a uniform distance apart, each of said pairs of rolls forming half, of said slits.

“3. The sheet metal slitting machine wherein are combined two pairs of slitting .rolls arranged one in advance of the other, said rolls being adapted to slit the sheet without bending the *569metal, and each roll being provided with a series of cutters extending the entire width of the sheet, and each pair of rolls forming slits in rows alternating with the slits formed by the cutters of the other pair.

“4. The sheet metal slitting machine wherein are combined two pairs of slitting rolls, one pair in advance of the other pair, and both provided with notched cutters extending the entire width of the sheet, and so arranged that the rows of slits formed by one pair alternate with the rows formed by the other pair, and so the slits in the different rows break joints, said cutters being also adapted to slit the sheet without bending the metal.

“5. The sheet metal slitting machine wherein are combined two pairs of slitting rolls arranged one pair in advance of the other, and both provided with notched cutters whose thickness equals the width of two strands of the slitted sheet, said cutters being arranged so the rows of slits cut by one pair of rolls alternate with the rows of slits cut by the other pair, and being adapted to cut the sheet without bending the metal.”

Curtis’s preliminary statement alleged conception and disclosure on October 15, 1900. That of Turnbull alleged conception and disclosure in August, 1897; construction of model December 1, 1901; and reduction to practice in April, 1902.

The Examiner of Interferences awarded priority to Curtis upon all five counts of the issue. The Examiners-in-Chief affirmed the decision as to counts 2, 3, 4, and 5, and reversed it as to count 1. They also called the attention of the Commissioner, as permitted in Hule 126, to the fact that Curtis had no right to make a claim to count 1.

Curtis took no appeal, and his claim to count 1 is therefore settled against him.

Turnbull appealed to the Commissioner, who affirmed the decision of the Examiners-in-Chief.

The burden of establishing priority, imposed upon Turnbull as the last to file application, has, under the settled rule, been greatly increased by the concurring decisions of the several tribunals of the Patent Office in favor of his opponent.

These tribunals concurred in finding that Turnbull conceived ..the invention of the issue about the date alleged, namely, August, *5701897, and the fact is conceded by Curtis. They also concurred in finding that Curtis conceived it late in the fall of 1900. Error is assigned by the appellant on this finding, and he contends that Curtis must he confined to the date .of his application for conception and disclosure, because there is not sufficient evidence of an earlier date. The importance of establishing the earlier date lies in this, that the decision against Turnbull ■was founded on the further conclusion that he was not exercising diligence in perfecting his invention when Curtis entered the field.

As the decisions in the record show the grounds for awarding the earlier date of conception, it is sufficient to say that Curtis’s evidence on the point was clearly corroborated by the witness Bradford, whose intelligence and capacity to understand and explain the disclosure made by Curtis are apparent. Although deeply interested in the result, he stands unimpeached. The few surrounding circumstances that shed any light upon the question tend to support Curtis’s claim to the earlier date; and none are inconsistent with it. We would not be justified, therefore, in sustaining the contention.

It remains to consider whether it was error to hold that Turn-bull lost the benefit of his earlier conception because he was not •exercising diligence in perfecting his invention at the time that Curtis entered the field. In this conclusion, also, all of the Patent Office tribunals have agreed.

As the evidence has been fully reviewed, both in the decision of the Examiner of Interferences and of the Commissioner, it is unnecessary to repeat it. It shows, substantially, that during Bis more tBan three years of inaction, Turnbull applied for six patents for other invention, and that, while poor, he had the available means to make an application for this one. It does not appear that his delay was due to the fact that he was laboring upon some closely related device, under conditions that excused that delay, as in the cases of McCormick v. Cleal, 12 App. D. C. 335; Christensen v. Ellis, 17 App. D. C. 498, and some others that are analogous. The real ground of delay, as disclosed by his own evidence, was that he thought it to his interest to withold his application until he might be able to *571make an advantageous arrangement with some person of large capital for the exploitation of the invention. Such an excuse is insufficient. See Berger v. Dodge, 24 App. D. C. 476, 485; Wyman v. Donnelly, 21 App. D. C. 81, 87.

It follows that the decision appealed from must be affirmed. It is so ordered, and, further, that this decision and the proceedings in this court be certified to the Commissioner of Patents. Affirmed.