specially concurring:
I can not agree with the conclusion of the majority of the court that there was no lack of diligence upon the part of appellee in reducing his invention to practice.
The rule is so well settled that it scarcely needs the citation of authority that the reasonable diligence required of the first inventor, where another has entered the field and has reduced an invention to practice prior to the first inventor’s reduction to practice, is diligence in perfecting and adapting his invention. Automatic Weigh*903ing Mach. Co. v. Pneumatic Scale Corp., 166 F. 288. The rule is also well established that in such cases the first inventor, to be entitled to an award of priority, has the burden of showing that immediately before his rival entered the field, and at that time, he was exercising due diligence in perfecting his invention and attempting to reduce it to actual practice. Martocello v. Kobash, 17 C. C. P. A. (Patents) 1095, 39 F. (2d) 677.
Applying these two principles to the case at bar, I think the record shows that appellee did nothing from the date of his conception in 1919 until some time between October 29 and November 26, 1924, to reduce his invention to practice. Appellant entered the field on September 10, 1924, and the majority opinion rests its finding of diligence upon the following statement contained therein:
We flunk that it has been clearly established by appellee that he conceived the invention early in 1919; that he and some of his associates in the employ of the S. Morgan Smith Co. had discussed the question of the installation of the invention in hydraulic turbines from time to time, especially on July 29 and August 28, 1924, and thereafter; that, due to the fact that the vanes in turbines theretofore constructed by appellee’s company were too narrow or otherwise unsuitable to be used with inside stop pins, it was impossible on August 28, 1924, for appellee to make practical use of the invention; that, on August 28, 1924, it was understood by appellee and the witness, Jessop, chief engineer of appellee’s assignee, that the invention would be utilized as soon as an order was received for the construction of a turbine; that, early in October, 1924, an order for a turbine was received and immediately thereafter and until January, 1925, the use of the invention, as a part of the turbine to be constructed, was many times considered and discussed by appellee and others in the employ of the Í3. Morgan Smith Co.; that drawings for the vanes of this turbine were prepared in October, 1924, pencil drawings of the invention being added thereto shortly thereafter and prior to November 26, 1924; and that the invention was actually installed in this turbine early in the year 1925.
I bad not supposed that discussion of an invention involving only the. question of its use at some time in the future was any evidence of diligence in reducing it to practice. The record does show that appellee discussed with his fellow employees and officers of the company by which he was employed the question of whether his invention should be installed at some time in the future in a turbine. Appellee testified that in August, 1924, in conversation with George A. Jessop, chief engineer of appellee’s employers, “ it was decided to put in inside gate stops on the first available order received after August, 1924.” The record shows that the first “ available order ” was received in October, 1924, but that it ivas not decided until January, 1925, that the gate stops embodying the invention in issue-should be installed in the turbine covered by that order.
In the case of Seebevger v. Dodge, 24 App. D. C. 476, one of the-questions there under consideration was very similar to the question, here under discussion. In that case the court said, p. 485:
*904Granting tlie contention that actual reduction to practice is preferable to that which is constructive, merely, as more to the interest of the public, and that reasonable indulgence ought to be extended to one pursuing that course in good faith, yet, when the construction of an experimental device involves no great cost and risk that an inventor, though possessed of sufficient means, may well hesitate to undertake the same entirely at his own expense, due diligence requires that he should then attempt to secure his right and promote the public interest by filing an application for a patent.
So here, if the invention could not be reduced to practice except by installation of the same in a very large and costly machine, instead of waiting for some indefinite time in the future to embody the invention in such machine, due diligence required that appellee file his application for a patent upon it and thus secure a constructive reduction to practice of the same. This he did not do before appellant’s reduction to practice.
It seems to me that the majority opinion modifies the rule as to what constitutes diligence in reducing an invention to practice. If mere discussion of whether a proposed invention should be used commercially in the future, or even a tentative understanding that it shall be so used, is evidence of diligence in reducing an invention to practice, then I think that we have so broadly extended the rule of diligence as to destroy, in many cases, its proper application.
On the other hand, if it be conceded that mere discussion of the future use of an invention is not evidence of diligence, then it seems to me that the conclusion of the majority upon the question of diligence can not be sustained unless it be held that diligence by the first inventor, beginning more than a month after the second inventor had 'entered the field, is in this case sufficient to entitle him to an award of priority. It seems to me that the reason for the rule that diligence upon the part of the first inventor must exist immediately prior to the time the second inventor enters the field is that any diligence of the first inventor first arising after the second inventor enters the field might be the result of his gaining some information concerning the ■activities of the second inventor. I believe that it is a wise and salutary rule that diligence must be shown immediately before and at the time that the second inventor enters the field, and that any diligence exercised by the first inventor only after the second inventor ■enters the field can not avail the first inventor as against the claim of the second inventor, who has reduced his invention to practice before the reduction to practice by the first inventor. In the case at bar, there was at the very least a period of more than one month after the second inventor entered the field during which appellee exercised no diligence in reducing his invention to practice, according to the evidence in the record, and there is no evidence that he was exercising such diligence before appellant entered the field. For the reasons *905stated, assuming that the second inventor was the first to reduce to-practice, I can not agree with my brethren that appellee was in the exercise of such diligence in reducing his invention to practice as to entitle him to an award of priority.
Upon the question of reduction to practice, appellee’s patent having been issued more than four months prior to the filing of the application of apxiellant, the burden was upon appellant to establish priority of invention beyond a reasonable doubt. I am frank to say that were this a case where preponderance of evidence only was required, I should be of the opinion that appellant had sufficiently established reduction to practice of his invention prior to appellee’s filing date, but I do agree with the statement in the majority opinion that the evidence is somewhat unsatisfactory in this respect. The record clearly shows that it was practical to determine the necessary size of the gate stops by certain mathematical computations, without resorting to an actual test. While it may be found from the testimony that such computations were made and relied upon, there is no direct evidence in the record that the party who made such computations was qualified to do so, and there is no direct evidence that any person qualified to pass upon and determine the strength of the pins actually did so. For this reason, I can not say that appellant has established priority of invention beyond a reasonable doubt, and I therefore concur in the conclusion of the majority that the decision of the Board of Appeals should be affirmed.
DISSENTING OPINION
Bland, Judge: I regret that I find myself totally out of harmony with the majority in the conclusion reached, and in that portion of the opinion having reference to reduction to practice. While the conclusion is said to be reached on the issue of the diligence of the appellee, the reduction to practice of appellant is discussed in such a manner as to leave the definite impression that the majority, at least, has very grave doubts as to whether or not appellant reduced his invention to practice.
This court usually follows the commendable practice of not discussing or intimating its views upon questions which it does not care to decide and which are not essential to the decision of the case. The reduction to practice of appellant is not in this case according-to the views of the majority, and yet the question is discussed. A conclusion that there was no reduction to practice on the part of appellant adds no strength to nor sheds any light upon the .very unsatisfactory testimony as to appellee’s diligence. I fail to find *906any relevancy between the two issues. Appellee either was or was not diligent, without regard to appellant’s acts. In my judgment the concurring opinion of my associate, Judge Lenroot, conclusively shows the lack of diligence on the part of appellee.
To my way of thinking, this is one of the peculiar kinds of inventions which does not require such a reduction to practice as that it be installed and operated until the contingency happens which is to call into operation the patented device. Following the logic of the opinion of the majority, it would not have been sufficient to constitute reduction to practice to have put the completed device in actual operation under normal conditions because the invention was not designed to operate under normal conditions, but to operate ■under abnormal conditions. The chain held the vane in normal ■conditions, but broke and permitted the stop pins to stop the vane when a log or some obstruction came against it with greater force than the normal flow of water. Putting the vane in normal operation would not test the strength of the pins until the chain broke. To hold that a reduction to practice of this kind of device requires that it must be tested -under abnormal conditions would, under the «circumstances, I think, be unreasonable. No such requirement was made of appellee, because of the rule that filing of the application constitutes reduction to practice. The courts should not make a rule in a case of this character which puts the parties, while in the Patent Office, upon such an unequal basis. The practical result in this kind of case is that the first one to the Patent Office is declared to be entitled to the invention.
There is ample supporting authority for my views on this question, although none of the cases contains a statement of facts identical with those at bar. The peculiar nature of the device in question would, to me, seem to warrant the application of the rule laid down in Mason v. Hepburn, 13 App. D. C. 86, 1898 O. D. 510, in which a clip or attachment to a gun was held to have been reduced to practice when it was completely finished and ready for sale and use and was demonstrably capable of producing the result.
The entire record before us unquestionably shows that at the time appellant claims his invention had been reduced to practice, it had been fully ascertained that it was capable of producing the result for which it was invented and that it was completely finished and ready for sale and use. See also Rolfe v. Hoffman, 26 App. D. C. 336.