ficially enjoyed by the public; which the law decides is a patentable subject.1 In these and other cases where the question arises, upon all the facts attending and surrounding the alleged invention, whether it is a patentable subject, it is for the court to settle that question. Of course the novelty of the invention is a prerequisite to the validity of the patent, and this is a question of fact; but the alleged invention being ascertained to be new, it is still to be determined whether it is that species of invention to which the law gives the protection of a patent.

§ 469. The question of infringement is, as has already been stated, a question whether the invention of the defendant is substantially the same thing as that of the plaintiff. The identity of two things is a matter of fact, depending upon evidence; and although it is to be determined under the guidance of those principles which determine what constitutes identity and diversity in the sense of the patent law, yet it is for the jury to determine, as matter of fact, under proper instructions, whether the two things are the same or different.2

This is true even where there is no dispute as to the particular process or machine employed by the defendant, but only whether that process or machine is an infringement. The court cannot compare the plaintiff's invention with that which is used by the defendant and say that the two are identical.3

For a full discussion of the question, what is proper evidence of the infringement, by means of chemical equivalents, of a chemical process, see Heath's patent and the numerous decisions elicited by it, supra, chapter on Infringement.

1 Crane v. Price, Webs. Pat. Cas. 408, 409.

Boulton v. Bull, 2 H. Bl. 463; Whittemore v. Cutter, 1 Gallis. 478; Pennock v. Dialogue, 4 Wash. 538; Lowell v. Lewis, 1 Mason, 191; Phillips on Patents,

431.

Delarue v. Dickenson, 7 Ell. & Blackb. 738. Compare a similar question as to the provinces of court and jury on the issue of novelty, at the commencement of the present chapter.

* 2 Webs. Pat. Cas. 213; 32 E. L. & Eq. 45.

CHAPTER XII.

EVIDENCE.

§ 470. THE evidence appropriate to the different stages of a patent cause may be divided into (1.) the evidence of title, and (2.) the evidence upon the point of infringement. Evidence of title relates to the letters-patent and the plaintiff's interest therein, the novelty and utility of the invention, and the sufficiency of the specification. Evidence of the infringement relates to the identity of the thing made, used or practised by the defendant, with the invention of the patentee.

§ 471. I. As to the plaintiff's title. With regard to the letterspatent, the statute of 1836, §§ 4, 5, makes a copy under the seal of the Patent Office and the signature of the commissioner competent evidence that a patent has been granted by the government for the invention described in the specification annexed. If the patent produced in evidence refers to the description in a former patent, it is necessary to produce and read that former patent, in order to show what the invention is, if it is not made entirely clear and intelligible by the patent on which the action is brought.1

§ 471 a. Where the patentee has surrendered his original patent and taken out a reissue with an amended specification, the action of the commissioner of patents in granting the reissue is conclusive evidence upon the question of "inadvertence, accident, or mistake." The decision of the commissioner is not re-examinable elsewhere, except upon the ground of fraud or evident want of jurisdiction. Such is the ruling of the Supreme Court in the case of Stimpson v. Westchester Railroad,2 confirming the decision in Woodworth v. Stone, under the provisions of the act of 1836, ch. 357, § 13, although the same court had previously decided, in the case of Philadelphia and Trenton Railroad v. Stimpson, that 1 Lewis v. Davis, 3 Carr. & Payne, 502. A drawing filed subsequent to the destruction by fire of the original patent is admissible in evidence. Emerson v. Hogg, 2 Blatchf. 1.

24 How. 380.

33 Story's R. 749.

14 Pet. 448.

the action of the commissioner was only prima facie evidence. The opinion of Judge Story in the case of the Philadelphia and Trenton Railroad, as cited in the note to the following paragraph, must accordingly be understood with this modification. (Vid. on this topic the chapter on Proceedings at the Patent Office.) So also, in the case of an extension of the term of letters-patent, the action of the commissioner is conclusive evidence of all the facts that he is required to find, and is impeachable only for fraud.1 The signature of one styling himself "acting commissioner," attached to letters-patent, is sufficient in controversies between the patentee and third parties.2

§ 472. The letters-patent being thus proved to have issued, they are prima facie evidence that the patentee was the first inventor of the thing patented. The reason upon which this is held is, that our statute requires the patentee to make oath that he is the first and true inventor of the thing; and when the patent has issued, supported by this oath, the burden of proofs is cast upon the party who would object, to show that the grant has been improperly obtained by the patentee; because the law presumes, in the first instance, that the patent has been granted upon the proofs which the statute requires to be laid before the officers of the government, and that those proofs were satisfactory.*

1 Clum v. Brewer, 2 Curt. C. C. 506; Colt v. Young, 2 Blatchf. 471.

2 Woodworth v. Hall, 1 Woodb. & Min. 248, 389.

Alden v. Dewey, 1 Story's R. 336; Woodworth v. Sherman, 3 Story's R. 172; Stearns v. Barrett, 1 Mason, 153. It is also held in England, that the patent is primâ facie evidence, on the part of the person claiming the right, that he is so entitled. Minter v. Wells, Webs. Pat. Cas. 129.

In the Philadelphia and Trenton Railroad Company v. Stimpson, 14 Peters, 458, Mr. Justice Story, delivering the opinion of the Supreme Court of the United States, said: "Now the objection is, that the present patent does not contain any recitals that the prerequisites thus stated in the act have been complied with, viz., that the error in the former patent has arisen by inadvertency, accident, or mistake, and without any fraudulent or deceptive intention; and that without such recitals, as it is the case of a special authority, the patent is a mere nullity and inoperative. We are of opinion that the objection cannot, in point of law, be maintained. The patent was issued under the great seal of the United States, and is signed by the President, and countersigned by the Secretary of State. It is a presumption of law, that all public officers, and especially such high functionaries, perform their proper official duties until the contrary is proved. And where, as in the present case, an act is to be done, a patent granted upon evidence, and proofs to be laid before a public officer, upon which he is to decide, the fact that

Where the defendant wishes to set up a merely equitable title against one who possesses the full legal title, he must distinctly allege such defence in his answer, and establish it on the title. The burden of proof is against him.1

§ 473. When the patentee wishes to strengthen this evidence, either in the opening of his case or to rebut any evidence offered by the defendant which may have tended to show that he was not the first inventor, he can only call persons who were in the way of hearing of the invention if it had existed before, to testify that they have not heard of it. The proposition which the plaintiff has to establish is, strictly, a negative; he is to prove that the invention did not exist before; and therefore, as has been said, he must proceed by exhausting the affirmative instances of it, by calling those persons who might have known of it, if it had existed before, but who never have heard of it; and the more those persons, from their acquaintance with the particular trade or manufacture, were in the way of hearing of or meeting with it, the stronger the evidence will be.2

he has done the act or granted the patent is primâ facie evidence that the proofs have been regularly made, and were satisfactory. No other tribunal is at liberty to re-examine or controvert the sufficiency of such proofs, if laid before him, when the law has made such officer the proper judge of their sufficiency and competency. It is not, then, necessary for the patent to contain any recitals that the prerequisites to the grant of it have been duly complied with, for the law makes the presumption; and if, indeed, it were otherwise, the recitals would not help the case without the auxiliary proof that these prerequisites had been, de facto, complied with. This has been the uniform construction, as far as we know, in all our courts of justice, upon matters of this sort. Patents for lands, equally with patents for inventions, have been deemed primâ facie evidence that they were regu larly granted whenever they have been produced under the great seal of the gov ernment, without any recitals or proofs that the prerequisites under which they have been issued have been duly observed. In cases of patents, the courts of the United States have gone one step further, and as the patentee is required to make oath that he is the true inventor, before he can obtain a patent, the patent has been deemed primâ facie evidence that he has made the invention." See Pitts v. Hall, 2 Blatchf. 229.

1 Gibson v. Cook, 2 Blatchf. 144.

• Cornish v. Keene, Webs. Pat. Cas. 503; Galloway v. Bleaden, Ibid. 526; Pennock v. Dialogue, 4 Wash. 538. "The fact of making or exhibiting an article never before seen or heard of by the witnesses who prove the fact, is at least primâ facie evidence of invention, until other evidence is given to prove that the same article was invented, known or in use, at an antecedent period of time, and that the patentee had only embodied the conceptions and the discovery of some other person."

§ 474. Although this evidence is only general and negative, it is not, on that account, without weight. To illustrate its force as well as its proper office, we may suppose a case where the defendant had succeeded in showing that some prior inventor had made experiments in the same line as the patentee, and that this evidence goes so far as to show that that person had probably accomplished the same result as the patentee; but the point is still left in doubt, whether he had actually reached and perfected the invention for which the plaintiff has obtained a patent.1 The rule of law in such cases is, that if the prior efforts of some preceding inventor rested in experiment alone, his experiments, however near they may have been carried to the complete production of the thing, will not prevent a subsequent, more successful inventor, who has produced the perfect result at which both may have aimed, from obtaining a valid patent. The question for the jury will therefore be, in such cases, whether the efforts of the prior inventor rested in experiment alone, without coming to the point of completion, both in the theory and the actual application of the invention. Upon this question, the fact that the invention was never heard of until it was known to have proceeded from the present patentee, is of great weight. If it had been heard of among those persons who make it the business of their lives to know what is going on in the particular trade or art which it concerns, or to know what inventions in all arts or trades are from time to time produced, prior to the time when it was made by the patentee, the presumption would be very strong, that the person who is proved to have made near experiments towards it had actually accomplished the

1 The remarks of Nelson, J., in Many v. Jagger, 1 Blatchf. 372, seem to be here in point: "But there is one fact to which we will call your attention, that is entitled to some consideration, although it is not decisive. The James wheel was in general use on the Harlem R. R. in 1834, and to some extent on the New Jersey R. R. Baldwin in Philadelphia in 1835, and Tiers in the same city in 1836, one of them a year, the other a year and a half after the James wheel was in common use on these two roads, made trial to cast the double-plate wheel; and we think, on the evidence in the case, it is fair to infer that they made their experiments with full knowledge of the James wheel. . . . . If this inference be a fair one, and it is for the jury to say whether it is or not, then, with the James wheel before them, Baldwin and Tiers both failed to make a double-plate wheel. They had the idea of such a wheel in their minds, but were unable to perfect it. The conclusion would seem to follow, that the James wheel and the double-plate wheel were not necessarily identical, or that the former would necessarily lead to the latter without any ingenuity other than ordinary mechanical skill.”