the bringing of his invention into

use.

Time taken in conducting experiments with an invention is attended with the risk that the invention may be made by some other person in the meantime, or that the idea may come to the knowledge of some unscrupulous party, who will not hesitate to appropriate and patent as his own, the original conception of another, if it seem likely to prove at all valuable. As applications for patent are secret ex parte transactions, such theft might be consummated without the knowledge of the true inventor, until on applying for his patent, he should find another party already in possession of a patent wrongfully obtained. This probability, were there no check upon it, would prevent, by making too hazardous, that expenditure of time, money, and skill, which is necessary to reduce many original inventions to the best practical shape, and would compel the premature patenting of half-hatched ideas. This danger the law cannot entirely obviate, but it has provided some measure of protection to inventors during the time which may be required by them for conducting experiments to mature their ideas.

Section 40 of the act provides that any citizen of the United States who has made a new invention or discovery, and desires further time to mature the same, may file a caveat in the secret archives of the Patent Office.

Caveats

Are simply brief descriptions setting forth the design of an invention and its distinguishing characteristics, accompanied by a statement that the caveator who claims the invention as his own, is engaged in taking steps to perfect it, prior to applying for letters-patent. This caveat is filed in the secret archives of the Office, and is accessible only to the officials and the caveator, or such persons as he may duly authorize to have access to it. As a caveat refers to an avowedly uncompleted invention, while letters-patent are granted only for one which is complete, no proceedings are taken upon a caveat by the Office, but it remains for the caveator to mature his invention and file his application for a patent within one year; which time, however, may be extended from year to year by renewing the caveat. It is common to allude to caveats as affording a temporary security, thus leading many inventors to a mistaken impression that a caveat is a sort of temporary patent. This it is not; a patent being a grant of the exclusive right for a certain period to make, use, and sell a completed invention, is the act of the public in consideration of the disclosure of such completed invention. A caveat is merely the caveator's own act in reference to an incomplete invention which he desires to keep secret till he has had time to mature it, in order that he may then disclose it and obtain from

the public the exclusive right to make, use, and sell it. A caveat, therefore, is, as its name implies, simply a warning, notifying the Patent Office that the caveator has made an invention, which he intends to mature and to apply for a patent therefor within one year.

The effect which the law gives to this warning is to make it obligatory upon the Patent Office during one year after the filing or the renewal of a caveat, to grant no patent for the invention to any other claimant without giving the caveator opportunity to establish his priority of right. To this end, notice is to be given to the caveator of the filing of any interfering application for a patent, without, however, informing him as to the name or whereabouts of the applicant, and he is allowed three months from the time of such notice to complete his invention and file his application for a patent. If he fail to do this, he will be considered to have waived his claim, and that of the other applicant will be considered and passed upon without reference to the caveat.

Section 24 of the Patent Act pro vides, that any person who has invented or discovered any new and useful art, machine, manufacture, or composition of matter, or any new and useful improvement thereof, not known or used by others in this country, and not patented or described in any printed publication in this or any foreign country before

his invention or discovery thereof, and not in public use or on sale for more than two years prior to his application, unless the same is proved to have been abandoned, may, upon payment of the duty required by law, and other due proceedings had, obtain a patent therefor.

It is first to be noticed in this section that the term "any person' includes citizens and aliens, who in reference to the patent laws stand upon precisely the same footing.

And it may be here stated that an inventor, whether citizen or alien, who may have previously patented his invention in foreign countries, does not thereby prejudice his right to a patent here, provided that the invention has not been introduced into public use-by which is meant a use in public-in the United States for more than two years prior to his application for the patent, but his patent will expire at the same time with the foreign patent, or if there are several foreign patents, then with that having the shortest term, and in no case can the term of a United States patent exceed seventeen years from its date (section 25).

Next comes the recital of patentable subject-matters, and then the recital of conditions essential to the obtaining of a patent, and which of course therefore are essential to the maintenance of a patent which may have been granted.

These conditions are

1st. That the thing for which a

patent is sought shall not have been known or used by others in this country before the invention thereof by the claimant.

The mere knowledge or use of the thing in a foreign country will not, of itself, bar or invalidate a patent, and proof of such knowledge or use, except it be in the nature of a patent, or printed publication, is not admissible against a patent excepting where it is proposed, by bringing home to the patentee a knowledge thereof, to show that his claim of invention was not a bona fide claim, and that his patent was obtained by fraudulent representation. As to what knowledge or use in this country will suffice to bar or invalidate a patent, the rule would seem to be that it must not have been an entirely secret knowledge or use, but open so far as to argue accessibility by the public: beyond this it matters not how limited the prior knowledge or use may have been.

2d. That the thing for which a patent is sought shall not, prior to the invention thereof by the applicant, have been patented or described in any printed publication in this or any foreign country.

A prior patent for, or printed publication of, a similar thing is the best possible evidence of want of novelty in an invention, and to this end a foreign patent or printed publication is equally effective with a domestic one. In either case it is a record, accessible to the public, of the prior existence of the invention

claimed by the applicant or patentee as original with himself. But to bar an application or invalidate a patent, a prior patent or printed publication, whether domestic or foreign, should set forth the invention so clearly and intelligibly, as to enable a competent person skilled in that branch of the arts to which the alleged invention may appertain, to make or use it. Mere vague suggestions of something similar will not suffice.

In the absence, then, of any prior knowledge or use in this country, and of any patent or printed publication in this or any foreign country, an invention is new in the eye of the law, and the inventor has an inchoate right therein which he may perfect and secure by a patent.

He is not bound to apply for a patent within any specified time, nor will delay to do so, for however long a time, of itself, there being no other claimant, forfeit his right. The statute, however, points out two ways in which the right may be lost:

1. By public use or sale of the invention for more than two years prior to application for a patent.

Public use is a use, not by the public necessarily, but any usethough it may be only limited-in public, so that there may be public knowledge of the thing for more than two years.

As public use or sale for less than two years is not a bar to a patent, and as within such period an inventor might have made his invention

a source of profit to himself by manufacture and sale, or by allowing the use of it to others, it would not be right if under a patent subsequently obtained he could disturb or prohibit the further use of the articles thus previously sold by him, or which he had permitted to be made and used. It is therefore enacted by Section 37 that every person who may have purchased of the inventor, or with his knowledge and consent may have constructed, any newly invented or discovered machine, or other patentable article, prior to the application for a patent, or sold or used one so constructed, shall have the right to use, and vend to others to be used, the specific thing so made or purchased, without liability therefor.

The terms of this section exclude from its benefit those who may, prior to application for patent, have constructed or applied the invention, in defiance of the inventor's right, or without his assent or knowledge. 2. By abandonment.

An invention may be abandoned at any time prior to application for patent. But the law does not favor and will never raise, except in the case of public use or sale for more than two years, a presumption of the abandonment of an invention. Before it will be concluded that an invention has been abandoned, there must be some clearly proven act or expression on the part of the inventor, unmistakably indicating his intention not to claim any exclusive

right in the invention, but to allow it to become public property, for an invention can be abandoned only to the public at large.

As a rule, therefore, a valid patent may be obtained for any improvement which has not been known or used by others in this country, nor been patented or described in any printed publication in this or any foreign country before the date of its invention or discovery by the party claiming it as his own, unless he has allowed it to be in public use or on sale for more than two years before his application for a patent, or has at any time before such application by a voluntary and deliberate act abandoned it to the public.

Should the claim of an applicant for a patent be rejected, or should a patent granted be assailed in litigation, on the ground of a prior foreign patent or description in a foreign printed publication, if the applicant or patentee can establish by competent proof that his invention preceded the date of such prior foreign patent or publication, a patent will be granted him if he be an applicant; or, if he be a patentee, his patent will be sustained.

And, in the case of an applicant for a patent, ex parte evidence in such case suffices to establish his priority of right.

Such evidence is also competent to overcome the rejection of a claim for a patent on the ground of description in a printed publication in

this country, or a rejection on the ground that the invention is already in public use or on sale, unless it shall appear that such public use or sale has been for more than two years prior to the application for a patent.

But if application for a patent be made for something already patented in this country, or which another party is at the same time seeking to patent here, it may be necessary in either case to try the question of priority of invention in the Office. This is done by means of what is termed an interference— a judicial proceeding in which the rival claimants of the same invention are allowed to present testimony in support of their respective claims, the testimony being taken in the same mode as in a cause in equity, and each party having the right to be present at the examination of, and to cross-examine, his opponent's witnesses. This departure from the general rule, which makes applications for patents altogether ex parte proceedings, is necessitated by the circumstances of the case. The Patent Office can lawfully grant a patent only to the true and first inventor, and can lawfully grant a second patent for the same thing only to him who shall appear to be the actual true and first inventor, and therefore to have a claim superior to that of the first patentee. If, therefore, there be before the Office at the same time two or more parties, each claiming to be the true

and first inventor of the same thing; or, if application be made for a patent for the same thing, in which another party already has, by patent granted, a vested exclusive right, testimony must be adduced and proceedings had to determine the question of priority of invention. To these proceedings it is absolutely necessary that the rival applicants in the one case, or the applicant and prior patentee in the other, should both be made parties ; for by these proceedings their respective rights in the Patent Office are to be bound; and no man's rights are to be bound except by proceedings to which he is a party.

It is provided, therefore, by Section 42 of the Patent Act, that "whenever an application for a patent which, in the opinion of the Commissioner, would interfere with any pending application, or with any unexpired patent, he shall give notice to the applicants, or applicant and patentee, as the case may be, and shall direct the primary examiner to proceed to determine the question of priority of invention. And the Commissioner may issue a patent to the party who shall be adjudged the prior inventor."

Some years ago, the proceedings in interference cases were very loose and unsatisfactory. There was no mode of compelling the attendance of necessary witnesses; there was no system or order as to the time and mode of taking the testimony, and the parties were left to develop