delivered the opinion of the Court:

This appeal comes from the Patent Office, and is taken from the decision of the Commissioner of Patents made in what is termed an interference proceeding as between the claim of William P. Weber and that of George W. Flather to an invention or discovery of an amber varnish and the process of making the same. The question that has been considered by the tribunals of the Patent Office, and which is presented for decision on this appeal, is not in strictness the question of priority of invention or discovery of independent but interfering inventions or discoveries, but to which one of the two parties mailing separate applications for patent, does the right of original invention or discovery of the subject-matter described in the issue belong — each party claiming to be the sole and rightful discoverer of the subject-matter of the applications.

Plather is senior party, and filed his application on July 5, 1900. Weber filed his application December 24, 1900. *181This position of the parties on the record makes it incumbent upon Weber, the junior party, in order to prevail over the prior application of Flather, to establish by a preponderance of proof his alleged prior and superior claim to the invention or discovery, the subject-matter of the issue. The issue between the parties, as framed in the Patent Office, is as follows:

“ The herein-described process of dissolving amber in fatty oil, for the purpose of forming varnish, said process consisting in mixing the amber with the oil in the proportion of one pound of amber to not exceeding one and one-half pints of oil, heating the mixture in an open vessel to a temperature of not less than 600° Fahrenheit, until a scum consisting of particles of softened amber is formed over the entire surface, maintaining such coating of scum unbroken during the further heating of the mixture, whereby the mixture is brought to a temperature in excess of 700° Fahrenheit, and the particles of amber are gradually and completely dissolved in the oil.”

Testimony was taken by both parties, though most of the evidence produced on either side consists of the testimony of the parties themselves. The examinations of the parties, both on direct and cross-examination, were very protracted and long drawn out, and there is nothing more observable or striking in their testimony than their almost universal contradiction of each other in regard to nearly every material circumstance of the case, and, indeed, in regard to much that is not material. Weber was examined first and Flather replied. It would be difficult to arrive at a conclusion in the case, as to the real discovery of the matter of the issue, if it depended alone upon the testimony of the parties themselves. But there are other witnesses upon whose testimony more reliance can be placed, and there are some prominent circumstances of the case that speak for themselves, and whose significance cannot be perverted by any interested motive of statement.

Flather is a carpenter and builder by trade, and Weber is a musician, a violinist by profession, and seems to have a special fancy or passion for old violins and for attempting *182to discover the character of the varnish that was used in their manufacture or finish, supposing that their superior qualities depend in a large degree upon the varnish that was applied to them. He is strongly persuaded, it seems, that the varnish that was used in the making of the famous old Cremona violins was amber varnish, and one of the great objects of his life, for many years past, has been to discover the method by which to produce amber varnish, so that he could improve the violins of the present time. He has, however, been thriftless and impecunious, and Flather was and is a man of means, and being a neighbor and an intimate of Weber, both residing in the city of Washington, was willing to advance some small sums of money to aid and promote in making the discovery, in which Weber had great faith and confidence, and in which he seems to have enlisted the confidence and zeal of Flather. The matter was undertaken and experiments were made by the joint co-operation of the two; and it would seem that they did succeed in producing amber varnish, by experiments made by them — the experiments being made in the shed at the house of Weber. It is conceded that Weber was the mover and instigator of the whole effort to produce the vaimish now claimed to be successfully discovered. The counsel for Flather, in their brief, in referring to the evidence, say:

“ Manifestly Weber has been, in all this testimony, endeavoring to establish the belief that he had made the invention before he took Flather into the business. Weber undoubtedly did start Flather in the business by calling his attention to the alleged ‘ lost art ’ of amber varnish, and Flather never would have thought of this or known anything about it, except for Weber. He appreciated this fact. Weber suggested the field for invention and was morbidly anxious to get this varnish for fiddles, which then would be exactly like the old and highly-prized violins.”

This is a candid concession, and when taken in connection with the well-established and undisputed facts, that all the experiments that were made after Flather became interested, were made in the presence and with the co-operation of *183Weber, both taking an interest alike in tbe result sought to be produced by tbe experiments, and tbat tbe experiments were all made in Weber’s shed, it is difficult to conceive tbat Blather can now, in justice and reason, claim to be tbe sole .and exclusive inventor or discoverer of tbe varnish. Tbe most tbat he can or ought to claim is tbat of joint discoverer <or inventor. But be does not seem to be contented to rest ■on tbat claim.

Tbe examiner of interferences, upon full and careful examination of all tbe evidence, awarded priority to Weber; but upon appeal by Blather tbat decision was reversed by tbe examiners-in-chief, and priority was awarded to Blather by tbat tribunal. Upon appeal to the Commissioner of Pat-ents tbat decision was reversed and priority was awarded to Weber, as had been done by the examiner of interferences. The examiners-in-chief founded their opinion not upon tbe testimony produced by either of the parties, but solely and «exclusively upon the fact of seniority of application by Blather. They say:

“As we view tbe case it is immaterial whether Blather’s testimony is in part or wholly discredited, since the determination of the ease rests upon the fact of seniority, and not upon any testimony appearing in the record of either of the interferents.”

And in regard to a fact that has been much dwelt upon by counsel for Blather, tbat is to say, tbat Weber appears to have subscribed the application filed by and in the name of Blather, as a witness, and not as a joint applicant, the ■examiners-in-chief say:

“ Weber appears as a subscribing witness to the application of Blather. Weber’s explanation of this fact is, that being ignorant of the patent law, be supposed that the application was to be filed in the joint names of himself and Blather. He, however, admits that the application was Blather’s. Tbe ■evidence does not show that Weber was actually and intentionally deceived, although it may perhaps be true tbat be ■did not fully understand tbe transaction.”

That Weber did not intend to place himself in the posi*184tion simply of a disinterested witness by signing tbe application of Flatber, is made clear beyond donbt, by the circumstances attending tbe signing of tbe paper by Weber, and also by tbe facts as sworn to by both Weber and Flatber; their testimony tending to show that wbat was done was-done for and in tbe interest of both parties, and was for tbe purpose of perfecting tbe application about to be made,, for tbe benefit of both, whatever may have been tbe secret intention of Flatber at tbe time or subsequently. We therefore agree with tbe examiners-in-chief, that tbe signature of Weber as a witness to tbe application filed by Flatber is not a fact that can in fairness be construed, under tbe circumstances, against tbe claim of Weber and in favor of that of Flatber. But we do not agree with tbe examiners-in-cbief that tbe decision of tbe case should rest alone and exclusively upon tbe fact of seniority of application by Flatber. It is-very true that there is an irreconcilable conflict in tbe testimony of tbe two parties to this interference proceeding. Flatber not only .contradicts tbe principal facts testified' to by Weber, but be contradicts many of tbe principal facts proven by other witnesses. In such state of tbe case, it is simply out of tbe question that tbe testimony of Flatber should be taken to discredit and disprove tbe testimony of all other witnesses, and that bis testimony should be accepted as controlling. Tbe weight of tbe testimony of the-parties and its inherent probabilities must be considered in tbe light of all tbe circumstances of tbe case, and though conflict may exist, a rational conclusion may be drawn from wbat appears to be tbe real transaction as disclosed by the-surrounding circumstances — such circumstances as lend support to tbe credibility of- tbe testimony of one of tbe parties as opposed to that of another. We think tbe evidence-in this case abundantly proves that tbe conception of the-invention or discovery was not by Flatber but by Weber before Flatber was taken into the business; and that Flatber and Weber simply co-operated in tbe experiments to reduce tbe conception to practice.

It appears to be sufficiently established that tbe invention *185or discovery was reduced to practice, after a series of experiments which were performed in the presence of both parties, in Weber’s shed, during the first half of the year 1900. Elather claims that this reduction to practice was the sole result of his own independent experiments and discovery. Weber, on the contrary, contends that, although Elather stood over the stove and attended to the details of the operation, everything that was done was based upon his, Weber’s, conception and was performed under his supervision. Elather does not admit that Weber had anything at all to do with the invention or discovery, except to wait upon him, to run errands for him, and to stand in the door of the shed to prevent others from intruding.

The Commissioner has gone over the facts of the case with great care and his conclusion drawn from them would seem to be in all respects entirely satisfactory. He says:

“ The invention was reduced to practice in June, 1900, prior to the date of filing Elather’s application. This state of facts is admitted by both parties and must therefore be accepted as proved. The question is, which one of the two parties is entitled to this date of actual reduction to practice, or, in other words, which one is in law entitled to the grant of the patent.

“ The testimony of Weber that there was a partnership between himself and Elather for the purpose of making and exploiting the invention or discovery is corroborated by witnesses Lee and Boucher. There is much evidence of a general character which tends to support this testimony of Weber. Elather’s own actions until the date of his application tend to support Weber’s contention. Weber and Elather were certainly co-workers with respect to the discovery. Elather denies the partnership relation, so he cannot avail himself of it. Viewing Elather’s case, therefore, in its most favorable light, the facts are such, as shown by the testimony, that Elather’s claim of invention or discovery could only be sustained, if at all, on the theory of joint invention or discovery with Weber. Elather makes no such claim, however, nor is such claim made on the part of Weber. *186Under no circumstances, therefore, either in law or in fact can Elather be held to be the sole inventor of the issue. Weber, on the other hand, is entitled to be adjudged not only the first, but^the sole inventor of the invention of the issue. In either aspect of the case, that is, whether there was a partnership relation between Weber and Elather, or whether there was no such relation, Weber has effectually overcome the burden placed upon him by reason of the fact that he is the junior party; and after giving due consideration to the fact that his name appears as a witness to the signature of Elather’s application Weber is held to be the true inventor of the invention of the issue.”

This is the summing up and conclusion of the Commissioner of Patents, upon full and thorough examination of the facts of the case, and in which conclusion we entirely concur. The decision of the Commissioner is therefore affirmed, and the case with this opinion will be certified to the Commissioner of Patents, as required by law; and it is so ordered. Decision of Commisioner affirmed.