Here, again, there is a distinction, which was formerly much dwelt upon, and which gave rise to much discussion. The defendant, who is charged with infringement of a patent and raises the issue of novelty, may do so in two ways. He may simply allege that the plaintiff's invention is really no invention at all, but that it was in public use at the time the letters-patent were obtained. The evidence to support such an allegation would consist, then, of what is called evidence in pais, and as such, could be weighed and decided upon only by the jury. All that the court can do in such cases is to instruct the jury that if they are satisfied that the plaintiff's invention is borrowed from some third party, or substantially contained in some printed publication (i. e. where there is a dispute as to identity), or substantially in public use at the time of the alleged invention, they must find for the defendant.1 On this point all the decisions agree that in such cases the issue of novelty and identity is, under proper instructions, to be left to the jury. It was, however, supposed and the supposition lies at the foundation of a number of important English cases that where the defendant, in a patent suit, claims himself to be acting under a patent, or asserts that the plaintiff's invention is contained in a patent granted to some third party, in such a case the court alone, by virtue of its acknowledged authority to be the sole interpreter of written instruments, could pronounce upon the question of identity. In other words, the court could say that the process or the machine claimed in A's patent is identical with that of B. Thus, in Bovill v. Pimm,2 the Court of Exchequer say, "We think this is a question of law, where the facts are not disputed." Also, in the recent case (1860) of Betts v. Menzies, it was held by the Exchequer Chamber, on appeal from the Queen's Bench, that the comparison of two specifications was exclusively within the prov 3 Steiner v. Heald, 6 E. L. & Eq. 536, reversing s. c. 2 Carr. & Kirw. N. P. 1022. The patentee here had taken out letters-patent for the manufacture of garancine from spent madder. For a long while this spent madder had been worthless, although still containing a percentage of coloring matter. It was then discovered that by treating fresh madder with acid and hot water, all the coloring matter could be extracted. The plaintiff's invention consisted in treating the previous spent madder in the same way. Held by the Exchequer Chamber that it was a question for the jury, whether this was a new manufacture of garancine. 1 Stead v. Williams, 2 Webs. Pat. Cas. 126; Stead v. Anderson, Ibid. 147. ince of the court. The decision assumed that this point had been decided in Bush v. Fox,1 a case which had been before the House of Lords in 1856. In March, 1862, the case of Hills v. Evans 2 came up before the Lord Chancellor Westbury, and received from him a ruling in direct opposition to that of the Exchequer Chamber, in Betts v. Menzies. In rendering his decision his lordship entered into an elaborate discussion of the case of Bush v. Fox, and showed that the House of Lords, in that case, had not, as was commonly supposed, pronounced directly upon the question, but that the Exchequer, in giving their decision in Betts v. Menzies, had been misled by obiter dicta of Lord Cranworth in moving the vote of the House. In June, 1862, Betts v. Menzies came up to the House of Lords, on appeal from the Court of Exchequer Chamber. The decision of the Exchequer Chamber was thereupon reversed, and the ruling of Lord Westbury sustained. In Hills v. Evans the Lord Chancellor said: "Now the argument has been, that it is the duty of the court and the right of the court to construe these earlier specifications, and that if I found, from the specifications so construed, when collated and compared with the specification of the plaintiff's patent, that the invention described in the one was identical with the invention described in the other, the court might at once arrive at the conclusion that there was no novelty in the invention, and deal with the whole matter as matter of law, and not as matter to be submitted to the jury, and that undoubtedly is a question deserving of very serious consideration. It is undoubtedly true as a proposition of law, that the construction of a specification, as the construction of all other written instruments, belongs to the court; but a specification of an invention contains, most generally, if not always, some technical terms, some phrases of art, and requires generally the aid of the light derived from what are called surrounding circumstances. It is therefore an admitted rule of law, that the explanation of the words or techni cal terms of art, the phrases used in commerce, and the proof and results of the processes which are described (and in a chemical patent, the ascertainment of chemical equivalents), that all these are matters of fact, upon which evidence may be given, and upon which undoubtedly it is the province and right of a jury to decide. But when those portions of a specification are abstracted and made 1 38 E. L. & Eq. 1. 2 6 Law Times, N. s. 90. the subject of evidence, and therefore brought within the province of the jury, the direction to be given to the jury must be a direction given only conditionally; that is to say, a direction as to the meaning of the patent, upon the hypothesis or basis of the jury arriving at a certain conclusion with regard to the meaning of those terms, the signification of those phases, the truth of those processes, and the result of the technical procedure described in the specification. [Citing from the opinion of Baron Parke, in Neilson v. Harford.] Now, adopting that as the rule in the comparison of two specifications, each of which is filled with terms of art and with the description of technical processes, the duty of the court would be confined to this, to give the legal construction of such document taken independently. But after that duty is discharged, there would remain a most important function to be still performed, which is the comparison of the two instruments, when they have received their legal exposition and interpretation; and, as it is always a matter of evidence what external thing is indicated and denoted by any description, when the jury have been informed of the meaning of the description contained in each specification, the work of comparing the two and ascertaining whether the words (as interpreted by the court) contained in specification A do or do not denote the same external matter as the words (interpreted and explained by the court) contained in specification B, is a matter of fact, and is, I conceive, a matter within the province of the jury, and not within the function of the court. Granting, therefore, to the full extent the propriety of the expression of the rule which is here contained, and taking either specification as so interpreted, whether the two specifications that are brought into comparison do or do not indicate the same external matter must be determined by the jury, and not as matter of law by the court. And I find that this has been the case and the course adopted by learned judges in a great variety of reported cases at Nisi Prius.” The Chancellor then cites Muntz v. Foster, and Walton v. Potter, and proceeds to show that a seemingly contrary opinion, expressed by a former Lord Chancellor in Bush v. Fox, in moving the judgment of the House of Lords, was a mere obiter dictum, and not embraced in that judgment. 1 Similar language is employed by Lord Chancellor Westbury, in Betts v. Menzies, before the House of Lords: "My Lords, the 1 4 Best & Smith, 9 B. 996; 7 Law Times, N. s. 110. second question was this, 'can the court pronounce Betts's patent to be void, simply on the comparison of the two specifications, without evidence to prove identity of invention; and also without evidence that Dobb's specification disclosed a practicable mode of producing the result or some part of the result described in Betts's patent. The answer of the learned judges involves, therefore, two conclusions which are extremely material to the patent law. One is this, that even if there be identity of language in two specifications, remembering that those specifications describe external objects, even if the language be verbatim the same, yet if there be terms of art found in the other specification, it is impossible to predicate of the two with certainty that they describe the same identical external object, unless you ascertain that the terms of art used in the one have precisely the same signification and denote the same external objects at the date of the one specification as they do at the date of the other. And, my Lords, this is obvious; for if we take two specifications dated as the present are, one in 1804 and the other in 1849, even if the terms employed in the one were identical with the terms employed in the other, -supposing that each of them contained a term of art, e. g. a denomination of some engine, some instrument, some drug, some chemical compound, it might well be that the thing denoted by that name in 1804 is altogether different from the thing denoted by the same name in 1849. If it were necessary to enter into such a subject, I could give numerous examples-say in chemistry of things that were denoted by one name in 1804 and which have retained the denomination, but which, by improved processes of chemical manufacture, are at present perfectly different in their results, their qualities, and their effects, from the things denoted by the same name some forty or fifty years ago. It is perfectly clear, therefore, that if you compare two specifications, even if the language be the same, you cannot arrive at a certainty that they denote the same external object and the same external process, unless you enter into an inquiry, and ascertain as a fact, that the thing signified by the nouns substantive contained in the one specification are precisely the same as the things signified by the same nouns substantive contained in the other. In all cases, therefore, where the two documents profess to describe an external thing, the identity of signification between the two documents con taining the same description, must belong to the province of evidence, and not to that of construction." 1 In England, therefore, it must be regarded as settled by the court of ultimate appeal, that wherever there are terms of art employed, the court cannot compare two specifications and pronounce the inventions contained therein to be identical; and that the former cases holding a different doctrine are overruled. Thus, . Booth v. Kennard,2 as supporting the statement that the court may, on the issue of novelty, compare two specifications, is no longer law. The right of the court, however, to pronounce upon the patentability of an invention as there stated remains unaffected. § 447. It is, however, to be kept in mind that the patentee, who is the real inventor of some useful machinery or process, may, nevertheless, by an improper wording of his claim, avoid the whole patent. The jury may find, as a matter of fact, that he is the inventor of the various steps in the process or the various items in the machinery; and yet, if the claim is so clumsily drawn up as to comprise other matters of which the patentee is not the inventor, the court must pronounce the patent invalid, either in whole or in part. This principle lies at the foundation of the decisions in Kay's ill-fated patent for flax-spinning. Here the real invention consisted in macerating flax, and spinning it at a short ratch (two and a half inches) by machinery already known. The jury found for the patentee, Kay, that he was the inventor, and that his invention had been of great public utility. But, unfortunately, he claimed in his specification to be the inventor of the machinery, and the court (the House of Lords) held that such a claim was invalid.4 § 448. The question whether a renewed patent is for the same invention as the original patent is also a question of fact for the jury; as is likewise the question whether the invention has been abandoned to the public. 1 Compare Hills v. London Gas Co., 3 Hurls. & Nor. 920; 5 Ibid. 311. 22 Hurls. & Nor. 84; 1 Ibid. 527. * See chapter of Specifications, where this patent is discussed at length. Carver v. Braintree Manuf. Co., 2 Story's R. 432. • Pennock v. Dialogue, 2 Pet. 16; Grant v. Raymond, 6 Pet. 248; Shaw v. Cooper, 7 Pet. 313; McClurg v. Kingsland, 1 How. 202; Kendall v. Winsor, 21 |