invention had been described in a printed publication prior to the invention of the complainant. Seymour v. Osborne, 11 Wall. 555.

These several exhibits have been carefully examined; and the conclusion of the court is, that there is not found in any one of them a machine with a frame secured as described in the complainant's specification, to which a drill-spindle is attached by means of the device called a nut, with a hand-wheel and the described screw and the automatic feed devices, consisting of the ratchet carrying the drill-shaft, the pawl, and the spring keeping the lever in contact with the cam mounted on the hand-wheel, which is capable of being operated at two different speeds; nor is there found in any one of them the two kinds of feeding mechanism designed to be employed in the manner and for the purposes described in the complainant's specification. For these reasons, the court is of the opinion that the first and second defences set up by the respondents in their answer and amended answer must be overruled.

Evidence of a parol character was also introduced by the respondents, having some slight tendency to prove that the complainant is not the original and first inventor of the patented improvement; but it is so slight, and so manifestly insufficient to overcome the prima facie presumption arising in favor of the complainant, that the court does not deem it necessary to enter into the details of the evidence.

Suppose that is so, still it is insisted by the respondents that the improvement was in use in divers places in the United States prior to any alleged invention thereof by the complainant.

Before proceeding to examine the evidence in that regard, it is proper to remark that the defence as pleaded does not state how long the invention had been in public use, nor does the answer state any thing from which it can be inferred when the public use commenced, except that it was prior to any alleged invention thereof by the patentee.

Authority is given by the act of Congress to plead or set up in the answer that the invention had been in public use or on sale in this country for more than two years before the application for a patent. Rev. Stat. (2d ed.), sect. 4920.

Inventors may, if they can, keep their invention secret; and if they do for any length of time, they do not forfeit their right to apply for a patent, unless another in the mean time has made the invention, and secured by patent the exclusive right to make, use, and vend the patented improvement. Within that rule and subject to that condition, inventors may delay to apply for a patent; but the Patent Act provides, as before stated, that the defending party in a suit for infringement may plead the general issue, and, having given the required notice, may prove in defence that the patented invention had been in public use or on sale for more than two years before the alleged inventor filed his application for a patent, and the provision in that event is, that if the issue be found for the party setting up that defence, the judgment or decree shall be in his favor.

Different phraseology was employed in a prior Patent Act, which made it necessary for the party setting up such a defence to prove that the invention had been in public use or on sale, with the consent and allowance of the patentee, before his application for a patent was filed. 5 Stat. 123. Decided cases adjudicated under that act and certain earlier acts show that a very limited public use or sale of the invention, if prior to the application and with the consent and allowance of the patentee, was held to be sufficient to defeat the right of the inventor to the protection of the Patent Act. Pennock v. Dialogue, 2 Pet. 19; Whiting v. Emmet, Baldw. 310; Ryan v. Goodwin, 3 Sumn. 518; Wyeth v. Stone, 1 Story, 281.

Congress, however, interfered, and provided that no patent shall be held to be invalid by means of such purchase, sale, or use prior to the application of a patent, except on proof of abandonment to the public, or that such purchase, sale, or prior use has been for more than two years prior to such application. 5 Stat. 354.

Public use or sale, even under that provision, which was in the nature of an amendment to the earlier Patent Act, in order to defeat the right of the inventor to a patent, must have been for the period prescribed, with his consent and allowance. Pierson v. Eagle Screw Co., 3 Story, 305.

Unlike that, the resent Patent Act provides that the defending party, having given the requisite notice, may prove

that the invention has been in public use or on sale in this country for more than two years before the inventor applied for a patent, and that if that special matter is found in his favor he is entitled to the judgment or decree with costs. Nothing of the kind is pleaded in the answer, nor is there any thing in the record to support the proposition, if it had been well pleaded, from which it follows that the fourth defence must be overruled.

Two assignments of error, to wit, the second and the fifth, must not be passed over without comment. They are to the effect that the court erred in holding that the patentee was the original and first inventor of the respective improvements specified in the second and fourth claims of the patent.

Two objections to those assignments of error exist, each of which is sufficient to show that they cannot be allowed: 1. That there is no such defence set up either in the answer or amended answer. Nothing can be assigned for error which contradicts the record, nor can an appellant be allowed to assign for error the ruling of the court in respect to any defence not set up in his plea or answer. Appellate courts cannot amend the pleadings, nor can they allow that to be accomplished by an assignment of error. 2. Neither of those defences is pleaded as required by the act of Congress, as each is pleaded to a separate claim of the patent, and not to the invention which is embodied in the specification.

Such defences, if well pleaded to the invention described in the Patent Act, are good defences, as the act of Congress provides that the defending party may plead a general denial of the charge of infringement, and, having complied with the requirement as to notice, may give such special matters in evidence to defeat the patent. Under such a pleading and notice, the respondent in an equity suit may prove that the patentee was not the original and first inventor of the alleged improvement, or that it had been patented or described in some printed publication, or that the invention had been in public use or on sale in this country for more than two years prior to the application; and the provision is, that the judgment or decree must be in favor of the defending party, if he proves any one or more of these special matters.

Where the thing patented is an entirety, consisting of a single device or combination of old elements, incapable of division or separate use, the respondent cannot escape the charge of infringement by alleging or proving that a part of the entire thing is found in one prior patent or printed publication or machine, and another part in another prior exhibit, and still another part in a third one, and from the three or any greater number of such exhibits draw the conclusion that the patentee is not the original and first inventor of the patented improvement.

Attempts of the kind are sometimes made; but it is plain that the plea, which in the action at law is the general issue, is required to be addressed to the entire charge of the declaration, and that its effect is to cast the burden of proof upon the plaintiff to make good the charge of infringement. Infringement is the charge made by the party seeking redress; and it is competent beyond all doubt for the defending party to show that he does not infringe at all, or that he has infringed only a part of the claims of the patent. Authority for that proposition is found in the very nature of the issue between the parties; but the only authority for attacking the originality or validity of the patent is that given in the act of Congress, and consequently the attack must be made in the mode the Patent Act prescribes. Rev. Stat., sect. 4920.

Defences of the kind must, if the thing patented be an entirety, and incapable of division or separate use, be addressed to the invention, and not merely to one or more of the claims of the patent if less than the whole invention. More than one patent may be included in one suit, and more than one invention may be secured in the same patent; in which cases the several defences may be made to each patent in suit, and to each invention included in the bill of complaint. Gill v. Wells, 22 Wall. 24.

Combination patents may be mentioned as examples where more than one invention may be secured by a single patent, and in such a case the patentee may give the description of each combination in one specification. Cases of the kind often arise; and in such a case the party charged with infringement may plead and prove the statutory defences to each

invention, just as if the two combinations had been embodied in separate patents, for the reason that each combination in such a case, like what is secured in a division patent, must be regarded as a distinct invention, at least for the purpose of pleading the statutory defences to the charge of infringe

ment.

Ample support to that proposition is found in the language of the Patent Act and in the practice of the courts; but where the patent is an entire invention, incapable of division or separate use, the defences authorized by the act of Congress must be addressed to the thing patented, and the evidence to support the defence must show that the patentee was not the original and first inventor, or establish some one of the other statutory defences.

Patentees seeking redress for the infringement of their pat ent must undoubtedly allege and prove that they are the original and first inventors of the alleged improvement, and that the same has been infringed by the party against whom the suit is brought. In the first place, the burden to establish both of those allegations is upon the party instituting the suit; but the law is well settled that the patent in suit, if introduced in evidence, affords to the moving party a prima facie presumption that the first allegation is true, the effect of which is to shift the burden of proving the defence upon the defending party. Blanchard v. Putnam, 8 Wall. 42; Seymour v. 08borne, 11 id. 538. Infringement being denied, the burden of proof is upon the complainant to establish the charge.

Where the invention is embodied in a machine, manufacture, or product, the question of infringement, which is a question of fact, is ordinarily best deterinined by a comparison of the exhibit made by the respondent with the mechanism described in the complainant's patent. Both parties gave evidence upon the subject; but the weight of the proofs, in the judgment of the court, supports the affirmative of the charge.

Strong support to that view is derived from the stipulation filed in the case, in which the respondents admit that between the date of the patent and the filing the bill of complaint they made and sold drilling-machines with a vice attached, like complainant's exhibit B, which is equivalent to a confession of the

VOL. VIII.