delivered the opinion of the Court:

Each successive tribunal of the Office affirmed this decision. This unanimity increases the burden of the junior party.

We may assume that the finding as to Vincent’s conception is correct. The question upon which the case turns is the claim of reduction to practice. It appears that Vincent constructed a plate model of his invention in the spring of 1908, which has been produced in evidence. This model consists of two banks of white keys for setting up a multiplicand, and one bank of red keys for setting up the digits of a multiplier. Each bank of white keys controls a series of nine plates notched in accordance with the multiplication table, and there are also three sets of rack bars and three numeral wheels.

While several hand operations are required to perform a multiplication upon this model, it is contended that the issue does not preclude this method of operation. It is contended that the model is full size and made of materials usually used in the Burroughs Adding Machine. It is of limited capacity. The contention of Hopkins is that this is not a reduction to practice, but a device-constructed for study, and was not intended to be subjected to the tests necessary as a practice of the invention. The numbers on the dial wheel are upside down, and cannot be conveniently read. There is no mechanism for bringing the registry wheel back to zero after a computation has been made. The most that the machine can do is to multiply a single digit by a single digit, a computation easily performed without a machine. Finally, the various distinct hand operations do not constitute the automatic operation contemplated by the issue. The fixtures are attached to a steel plate and have not the appearance of a complete machine. Vincent ..admits that the only way in which the accumulating wheels can be cleared is by adding the necessary complementary numbers *599to them. The Examiner of Interferences said: “It is obvious that the plate model is operated in a manner radically different from that of the machine shown in Vincent’s application, since in the latter a partial rotation of the operating handle performs all of the necessary steps in obtaining the final result.”

Having examined the exhibit with an explanation of its action, we agree with the tribunals of the Patent Office that it cannot be considered a reduction to practice. It does not come within the class of crude devices capable of use sufficient to demonstrate their practical efficacy and utility, as in Coffee v. Guerrant, 3 App. D. C. 497, and other cases cited on behalf of appellant; it more nearly resembles the kind of machine claimed as a reduction to practice in Paul v. Hess, 24 App. D. C. 462.

The tribunals also decided that, notwithstanding the prior conception of Vincent, he had been lacking in diligence when Hopkins entered the field. The evidence amply sustains this conclusion.

The decision is affirmed and the clerk will certify this decision' to the Commissioner of Patents. Affirmed.