by such evidence as they could, such a case as they might choose. Consequently, the endeavor of each party was to make out his own case, by the light of that made out by his opponent; and there was every opportunity and temptation to the parties to adapt their proof to the emergencies of the occasion, rather than to the true facts of the case. It can hardly be doubted that the result must have been much injustice, and not a little false swearing.

Judicious improvements, however, in the law, and in the rules and regulations of the Patent Office, have, by assimilating the proceedings in interference cases as far as possible to those in a court of justice, given them a fair degree of the justice and certainty attending ordinary judicial proceedings.

The law has provided for securing the attendance of necessary witnesses by subpœna.

The rules of the Office have provided for proper system in the taking of testimony, by establishing that in all cases the prior patentee or earliest applicant for patent, shall be deemed prima facie the first inventor, thus putting him in the position of a quasi defendant.

The later applicant, therefore, or party complainant, must first take testimony to show the date of his invention, for which purpose a certain limit of time is allowed him, after which, within another set period, the prior patentee or appli

cant must take the testimony in support of his claim, and after the closing of all such direct testimony both parties may take rebutting testimony.

This right of rebuttal in both parties is necessary. The position of rival claimants of the same invention has not any real analogy to that of complainant and defendant in a suit, the analogy made by the rules of the Office being altogether artificial, and merely for the sake of convenience and order. To such cases no ordinary rules of pleading are applicable. Each party is, in fact, both plaintiff and defendant; there is, therefore, an equal right, as there may be an equal necessity in each party, to rebut his opponent's direct testimony, and it is convenient and orderly that all the evidence which is merely rebuttal of that of an opponent, shall be separate from the direct testimony adduced for the purpose of establishing a party's own case.

This is especially necessary in view of the circumstances in which many cases of interference originate.

We refer, of course, to those cases of frequent occurrence in which there has been some contact or communication, direct or indirect, between the respective parties, leading to a charge, either on one part, or mutual, of theft of the invention in dispute.

As ordinary rules of pleading are inapplicable to interference cases, and no such previous knowledge and

control is, therefore, had of the testimony to be adduced as those rules afford, it is essential to both parties to have the like right to rebut if they can, before the close of the evidence, such points as may be first raised in the opponent's testimony.

But these rules would not of themselves suffice to secure the fair trial and adjudication of cases of interference. Of course the main object of each party to an interference, is to establish a date of invention earlier than that proved by his opponent; and if, as under the old rules, the cases to be proved were left entirely in the dark till developed by the evidence, the party taking evidence last would have the opportunity, which he might not always scorn to use, to adapt his proof to the emergencies of the

case.

For a pretty effectual method of stopping such possible sharp practice, the public is indebted to the late Commissioner of Patents, Fisher, who established the following beneficial rule:

Before declaring an interference proper, a preliminary interference will be declared, in which each party, without being informed who the interfering claimant is, will be required to file a statement under oath, giving a detailed history of the invention, describing its original conception, the successive experiments, extent, and character of use, and various forms of embodiment, &c.

The statement of each party

is to be sealed, and not opened until at an appointed time by the examiner of interferences. If that officer then determines that the respective statements show a case warranting the declaration of an interference, he declares it, and neither of the opposing parties can have access to the statement of the other until the time for filing both has expired.

This rule certainly offers some check upon the subsequent proceedings, some bounds to the testimony to be adduced, by confining the parties to a particular case of their own showing, and by affording a basis for cross-examining an opponent's witnesses.

But the rule is serviceable in another way, as allowing the opportunity of nipping in the bud many interferences, which, if proceeded with, might result in nothing but useless expense.

Thus, it is provided, that if the party upon whom rests the burden of proof-i. e., the latest applicant fails to file a statement, or if his statement fails to overcome the prima facie case made by the respective applications-i. e., if the date of invention given by the later applicant should not be anterior to the date of application by the earlier -or if it shows that he has abandoned his invention, or that it has been in public use more than two years before his application, the other party will be entitled to an immediate adjudication of the case

upon the record: unless a presumption is created that his right to patent is affected by the alleged public use of the invention, in which case the interference may be proceeded with. This latter proviso is necessary because a determination against the right of one man to a patent cannot be made upon the ex parte statement of another. A person's ex parte sworn statement may be allowed to determine the question of his own right, but not that of the right of another. It is further provided that if the earlier applicant fail to file a preliminary statement, he will not be allowed to present any testimony going to prove that he made the invention at a date prior to his application.

The preliminary statements are not evidence for the parties making them.

Under the present law and office rules, then, cases of interferences may be regarded as a fair and efficient means of trying and determining questions of priority of invention, and a just ultimate decision may be expected in every case, for parties to such a case have the same rights of appeal from the Examiner to the Board of Examiners in chief, and from that Board to the Commissioner of Patents in person, as in other questions touching the rights of applicants for patents.

As regards the cases in which under the law the Commissioner may declare an interference, they include any and every case in which

there may arise adverse claims of invention, whether by reason of two or more contemporary pending applications for patents for inventions altogether or in some material part the same, or by reason of an application for a patent or for a reissue with a claim to something claimed or clearly shown in any patent or patents previously granted.

This power may be very beneficially used to check what was at one time a practice as common as it is mischievous, that of reissuing patents for the sole purpose of so extending their claims as to cover some feature of value in patents granted subsequently to those sought to be reissued.

In the case of an interference between an application for a patent and a patent granted, the power of the Commissioner extends only to granting another patent to the applicant, should he appear to have been the actual first and true inventor. He cannot recall or cancel the prior patent.

His office is in its nature ministerial, and concerns only the granting of patents; and his discretionary, or, what may be termed his quasi-judicial powers, therefore, are confined to the consideration and determination of such questions only as concern the granting of patents. His duty is to grant a patent to whomsoever may appear to be the true and first inventor of a patentable subject-matter, and justly entitled under the law to receive a

patent therefor.

In the execution of this duty it is necessary for him to consider and decide disputed questions of priority of invention; but with that and the grant or refusal of a patent, in accordance with his determination, his duty and power end.

The power of annulling or decreeing the invalidity of patents, or other public grants, is one of the chancery powers of the courts of the United States.

Consequently where, through the issue of an interference in the Patent Office, or through accident, there are two or more patents for the same thing, of which only one of course can be valid, the invalidity of the others can be authoritatively ascertained and decreed only by a court of the United States having jurisdiction of such questions.

Under Section 58 of the Patent Act: 66 Whenever there shall be interfering patents, any person interested in any one of such interfering patents, or in the working of the invention claimed under either of such patents, may have relief against the interfering patentee, and all parties interested under him, by suit in equity against the owners of the interfering patent; and the court having cognizance thereof, on notice to adverse parties and other due proceedings had, may adjudge and declare either of the patents void in whole or in part, or inoperative, or invalid in any particular part of the United States according to the in

terest of the parties in the patent or the invention patented. But no such judgment or adjudication shall affect the right of any person except the parties to the suit and those deriving title under them subsequent to the rendition of such judgment."

In the case of an interference in the Patent Office between an application and a prior patent, should the applicant be adjudged the prior inventor, the only measure of justice which the Commissioner has power to perform is, by granting a patent to the applicant, to put him in a position to avail himself, should he desire to do so, of the remedy presented by this section against the prior patentee.

The point to be adjudged in a case of interference is "priority of invention." The general rule is that he is in the eye of the law the first inventor who has first perfected and adapted the invention to use.

But this rule is subject to the qualification that he who first invents, i. e., mentally originates, shall have the prior right, if he were using reasonable diligence in adapting and perfecting the invention. Thus it is made by the statute a defence against a patent, that the patentee had surreptitiously or unjustly obtained the patent for that which was in fact invented by another, who was using reasonable diligence in adapting and perfecting the same.

It has been held that the words

"surreptitiously," or "unjustly," as here used, do not necessarily imply that bad faith on the part of the patentee must be shown to make this defence available. But it will be deemed that a patent has been wrongfully obtained, when it is for something which was in fact first invented by another than the patentee, if the prior inventor was at the time using reasonable diligence in adapting and perfecting the invention.

This reconciles the reference in our patent law of the doctrine that "he who is prior in time has the better right" to the time of the making of an invention, with the general maxim that "the laws serve the diligent, and not the slothful." A right of priority must be perfected by diligence.

The courts will not allow the plea of "prior invention" to overcome the title of a patentee whose patent was obtained in good faith, unless it be shown that the alleged prior inventor had actually reduced his conception to practice in a practically useful and operative form, or that being the first to invent, he was, at the time the patentee obtained his patent, exercising reasonable diligence to adapt and perfect the invention.

A mere prior conception of an idea, ending in experiment, and never reduced to that practical shape in which alone it can be useful to the public, and can attract public attention, will not suffice to

destroy the title of a patentee, who being himself a bona fide original inventor, has reduced the invention to successful practice, and published it by obtaining his patent.

By these judicially established principles the Patent Office is guided in determining the questions of "priority of invention," in cases of interference.

If the interference be between the claim of an applicant and that of a patentee, the prima facie presumption is in favor of the latter, and the burden is upon the applicant to show that he was the first inventor, and also that he had either actually reduced the invention to a practically operative shape before the interfering patent was obtained, or that at the time it was obtained, he was exercising reasonable diligence to bring it into such shape; and, furthermore, it must appear that the applicant has not unnecessarily delayed bringing his claim, but that he has been reasonably diligent, as well in bringing his application as in perfecting his invention. If he cannot show this, the first patent will not be disturbed by the grant of a second

Where the interference is between independent applicants for patents, there is not that strength of presumption in favor of either party which the possession of a patent, a vested right, creates still there is a presumption in favor of the earliest applicant, on the reasonable principle that, in the absence of proof to