law, or in the answer in equity, or set up at hearing.3 (g) PATENT DIFFERENT FROM APPLICATION.-That the invention claimed in the patent is substantially different from any invention described, suggested or indicated in the original application.4 (h) REISSUE INVALID.-That the reissue patent is invalid on account of its being reissued illegally.5 (2) UNLAWFUL EXTENSION.-That the patent had been unlawfully extended.6 (j) UNLAWFUL AMENDMENT BY REPRESENTATIVE. That the representative of the inventor subsequently unlawfully amended the application without making a new oath.7 (k) LACK OF TITLE IN PLAINTIFF TO BRING SUIT.-That the plaintiff is not the owner of the letters patent sued on or is not the sole owner; 9 that he is not the inventor10 or the sole inventor; 11 or of two claiming to be joint inventors that they are not such inventors. 12 knowledge, that there is no invention. Eclipse Mfg. Co. v. Adkins, 36 Fed. Rep. 554; West v. Rae, 33 Fed. Rep. 45; Blessing v. John Trageser etc. Copper Works, 34 Fed. Rep. 753. 1. Walker on Patents (2nd ed.), 446. But cannot be set up on pleas in equity. Walker on Patents (2nd ed.), § 594. 2. It is not necessary to state the facts intended to be proved in its support. Walker on Patents, § 599; Vana v. Campbell, 1 Black (U. S.) 430. 3. Slawson v. Grand St. etc. R. Co., 17 Blatchf. (U. S.) 512; s. c., 5 Bann. & Ard. Pat. Cas. 210; s. c., 4 Fed. Rep. 531; s. C., 24 Pat. Off. Gaz. 99; Gardner v. Hertz, 118 U. S. 1180; s. c., 35 Pat. Off. Gaz. 999; Mahn v. Harwood, 112 U. S. 354; s. c., 30 Pat. Off. Gaz. 657: 4. Walker on Patents (2nd ed.), §§ 440, 450, 603; Chicago etc. R. Co. v. Sayles, 97 U. S. 563; Kittle v. Hall, 29 Fed. Rep. 508; Eagleton Mfg. Co. v. West etc. Mfg. Co., 111 U. S. 490; Woodbury etc. Planing Mach. Co. v. Keith, 101 U. S. 479; Lindsay v. Stein, 10 Fed. Rep. 913; United States etc. Rifle Co. v. Whitney Arms Co., 14 Blatchf. (U. S.) 98; s. c.,2 Bann. & Ard. Pat. Cas. 293; S. C., 11 Pat. Off. Gaz. 373; Bevin v. East Hampton Bell Co., 9 Blatchf. (U. S.) 50; s. c., 5 Fish. Pat. Cas. 23. But a liberal construction is to be adopted in considering this question. Brush Electric Co. v. Julien Electric Co., 41 Fed. Rep. 679; Electrical Accumulator Co. v. Julien Electric Co., 38 Fed. Rep. 117. In equity where both the original and reissued patents are incorporated in the bill, this defense can be made by demurrer, otherwise by answer, though the broadening of claims after delay may be taken advantage of at the hearing. Walker on Patents (2nd ed.), §§ 610, 611 and 612; International Terra Cotta Lumber Co. v. Maurer, 44 Fed. Rep. 618. 6. See Extension of Patent, infra. Raised by special plea at law in equity by demurrer when sufficient facts appear on the record; otherwise by ansWalker on Patents 2nd. Ed. §§ wer. 525, 613. 7. This defense may be made with special notice, or setting it up in the answer. Eagleton Mfg. Co. v. West Bradley etc. Mfg. Co., 111 U. S. 490; s. c., 27 Pat. Off. Gaz. 1237. 8. See Parties Plaintiff, supra. Walker on Pat. 2nd. Ed. § 617; Providence Rubber Co. v. Goodyear, 9 Wall. (U. S.) 788; Dueber Watch Case Mfg. Co. v. Faley's Watch Case Co., 45 Fed. Rep. 697. 9. See Parties Plaintiff, supra. 10. See Invention, Diligence, supra. The manner of setting up this defense is same as above. 11. See Joint Inventors. ventors. 12. See Joint Inventors. ventors. Sole In Sole In The defenses of notes four and five (1) NON-INFRINGEMENT.-The non-infringement of the device by the defendant is a good defense.1 (m) LIMITATIONS. That the cause of action is barred by a statute of limitation.2 4. Defenses to Costs and Damages.-As a defense to plaintiff's claim for costs, defendants may aver an undue delay to enter a disclaimer; and the recovery of damages, that the goods were not marked patented in accordance with the law, and that no notice had been given of the fact of infringement1 5. Estoppel of Defendant to Set Up Certain Defenses.-An assignor, when sued by his assignee, is estopped from setting up the invalidity of the patent or his lack of title at the time of the assign must be made at law under special plea. Walker on Patents (2nd ed.), § 452. In equity they may be raised by a plea or in the answer. Walker on Patents, § 605. Adams v. Howard, 22 Blatchf. (U. S.) 47. 1. See article Infringement, supra. Whittemore v. Cutter, i Gallis (U. S.) 424; S. C., I Robb Pat. Cas. 28. How Made. This defense must be clearly set up in the answer. Jordan v. Wallace, 5 Fish. Pat. Cas. 185; Theberath v. Rubber etc. Trimming Co., 5 Bann. & Ard. Pat. Cas. 585; Sharp v. Reissner, 20 Blatchf. (U. S.) 10. Is admissible under general issue at law. Blanchard v. Puttman, 3 Fish. Pat. Cas. 186; Dunbar v. Myers, 94 U. S. 198; Eachus v. Broomall, 115 Ú. S. 434; Grier v. Wilt, 120 U. S. 412. And cannot be set up in special plea. Hubbell v. DeLand, 11 Biss. (U. S.) 382; s. c., 14 Fed. Rep. 471; 5. C., 22 Pat. Off. Gaz. 1883. 2. Whether the State statutes apply is doubtful. See Limitation, supra. Also McGinnis v. Erie Co., 45 Fed. Rep. 91; May v. Buchanan Co., 29 Fed. Rep. 469; May v. Cass Co., 30 Fed. Rep. 762; May v. Ralls Co., 31 Fed. Rep. 473: Prior to July 8, 1870, no U. S. statute of limitations applied to patent cases. Wood v. Cleveland Rolling Mill Co., 4 Fish. Pat. Cas. 550. This statute (Stats. at Large, vol. 16, § 55) provided that all actions for the infringement of patents be brought within six years from the expiration of the patent, was not re-enacted by the Revised Statutes. Robinson on Pat., § 980; May v. Logan Co., 30 Fed. Rep. 250; s. c., 41 Pat. Off. Gaz. 1387. The rights of action accruing under patents that expired during that time were subject to the rule. Hayden v. Oriental Mills, 22 Fed. Rep. 103. See on this subject, Sayles v. Richmond etc. R. Co., 3 Hughes (U. S.) 172; s. c., 4 Bann. & Ard. Pat. Cas. 239; s. c., 16 Pat. Off. Gaz. 43; Vaughan v. East Tennessee R. Co., 1 Flipp. (U. S.) 621; s. c., 2 Bann. & Ard. Pat. Cas. 537; s. c., II Pat. Off. Gaz. 789; Hayward v. St. Louis, 3 McCrary (U. S.) 614; s. c., 11 Fed. Rep. 427. This defense must be especially pleaded or it will be disregarded. Neale v. Walker, 1 Cranch (C. C.) 57; 1 Chitty on Pleading 498; Walker on Patents (2nd ed.), § 471. Several pleas covering different times may be filed. Hayden v. Oriental Mills, 22 Fed. Rep. 103. In equity this defense is made under demurrer, where the bill states the time within which the infringement was committed; otherwise by plea or ans wer. Walker on Pat. (2nd ed.), § 622; Adams v. Bridgewater Iron Co., Fed. Rep. 179. 3. See Disclaimer, supra. This defense must be made in an action at law by special plea; in equity by answer or plea. Walker on Patents, §§ 456, 609. In answer only. Worden v. Searls, 21 Fed. Rep. 574. 4. See Failure to Mark Patented Article, infra; U. S. Rev. Stats., § 4900; Goodyear v. Allyn, 6 Blatchf. (U. S.) 33. See Marking Article Patented, infra. Should be made at law by special plea. Walker on Pat. (2nd ed.), 463. In equity by plea or in the answer. Walker on Pat. (2nd ed.), § 616. In answer only. Sessions v. Romadka, 21 Fed. Rep. 124. 5. Time Tel. Co. v. Heimner, 19 Fed. Rep. 322; Curran v. Burdsall, 20 Fed. Rep. 835; Rumsey v. Buck, 20 ment; nor can one who has acknowledged in some agreement, for value, complainant's rights, afterwards dispute them.2 XIII. PLEA IN EQUITY.-The plea must present a single point going to a complete defense.3 Setting it down for argument is Fed. Rep. 697; Burdsall v. Curran, 31 Fed. Rep. 918; Parkhurst v. Kinsman, 1 Blatchf. (U.S.) 488; Newell v. West, 13 Blatchf. (U. S.) 114; Underwood v. Warren, 21 Fed. Rep. 573; Parker v. Mckee, 24 Fed. Rep. 808; s. c., 32 Pat. Off. Gaz. 137; Alabastine Čo. v. Payne, 27 Fed. Rep. 559; American Barrel Co. v. Laraway, 28 Fed. Rep. 141; Burdsall v. Curran, 31 Fed. Rep. 918; Adee v. Thomas, 41 Fed. Rep. 343An assignor cannot acquire a prior patent against his assignee. Curran v. Burdsall, 20 Fed. Rep. 835See, however, King v. Gedney, 20 Law. Rep. (U. S.) 631. 1. Newell v. West, 13 Blatchf. (U. S.) 114; s. c., 2 Bann. & Ard. Pat. Cas. 113; s. c., 8 Pat. Off. Gaz. 598; Herbert v. Adams, 4 Mason (Ü. S.) 15. See, however, Kearney v. Lehigh Valley R. Co., 27 Fed. Rep. 699. For examples of other estoppels preventing defenses to patents, see Carroll v. Gambrill, 1 McArthur Pat. Cas. 581; Downton v. Yeager Milling Co., McCrary (U. S.) 26; s. c., I Fed. Rep. 199; s. c., 5 Bann. & Ard. Pat. Cas. 112; s. c., 17 Pat. Off. Gaz. 906; Time Tel. Co. v. Carey, 22 Blatchf. (U. S.) 34; s. c., 19 Fed. Rep. 322; s. c., 26 Pat. Off. Gaz. 826. But the fact that the defendants have adopted the complainant's device bodily, and have used and sold it in preference to prior structures, does not estop them from questioning its patentability. Simmonds v. Morrison, 44 Fed. Rep. 757. 2. Baltimore Car Wheel Co. v. North Baltimore etc. R. Co., 21 Fed. Rep. 47; Eclipse Windmill Co. v. May, 17 Fed. Rep. 344; Washburn etc. Mfg. Co. v. Cincinnati etc Co., 22 Fed. Rep. 712; Pope Mfg. Co. v. Owsley, 27 Fed. Rep. 100; Morse Arms Co. v. United States, 16 Ct. of Cl. 296; Clark v. Amoskeag Mfg. Co., 62 N. H. 612. An estoppel of a licensee does not arise when the licensee stands out from under his license. Brown v. Lapham, 23 Blatchf. (U. S.) 475; s. c., 27 Fed. Rep. 77; s. c., 37 Pat. Off. Gaz. 676. Or where the complainant elects to treat licensee as infringer. Baltimore Car Wheel Co. v. North Baltimore etc. R. Co., 21 Fed. Rep. 47. A grantee of a patent is not estopped from denying its validity out of his territory. Hobbie v. Smith, 27 Fed. Rep. 656. 3. Reissner v. Anness, 3 Bann. & Ard. Pat. Cas. 148; s. c., 12 Pat. Off. Gaz. 842; White v. Lee, 4 Fed. Rep. 916; Graham v. Mason, 4 Cliff. (U. S.) 88; s. c., 5 Fish. Pat. Cas. 1; Giant Powder Co., v. Safety Nitro Powder Co., 10 Sawy. (U.S.) 23; s. c., 19 Fed. Rep. 509; s. c., 27 Pat. Off. Gaz. 99; Secombe v. Campbell, 18 Blatchf. (U. S.) 108. A plea is intended to dispose of the case on a single issue; it will not be allowed where it will cause the case to be tried piece meal. Giant Powder Co. v. Safety Nitro Powder Co., 19 Fed. Rep. 509. Where the plea is double the respondent may elect which ground he will stand on. Reissner v. Anness, 3 Bann. & Ard. Pat. Cas. 148; s. c., 12 Pat. Off. Gaz. 842. And permission may sometimes be obtained to plead double. Winne v. Snow, 19 Fed. Rep. 507. Defenses Which May be Set Up by Plea.Non-joinder of necessary party. Hammond v. Hunt, 4 Bann. & Ard. Pat. Cas. 111; Wallace v. Holmes, 9 Blatchf. (U. S.) 65; s. c., 5 Fish. Pat. Cas. 37; s. c., 1 Pat. Off. Gaz. 117; Goodyear v. Toby, 6 Blatchf. (U. S.) 130. That the complainant alleged to be a corporation is not incorporated. Goodyear Dental etc. Co. v. Wetherbee, 3 Cliff. (U. S.) 555; s. c., 3 Fish. Pat. Cas. 87. Lis pendens, Wheeler V. McCormick, 8 Blatchf. (U. S.) 267; 4 Fish. Pat. Cas. 483. That reissue is void as not for same invention as original. Hubbell v. DeLand, 12 Pat. Off. Gaz. 1883. That the plaintiff is only a licensee. Cottle v. Krementz, 25 Fed. Rep. 494. To the jurisdiction of equity that the patent has expired. Edison Electric Light Co. v. United States Electric Light Co., 35 Fed. Rep. 134. That the defendants had settled the damages. Burdell v. Denig, 15 Fed. Rep. 347. That defendant is suing on a patent which has been surrendered for reissue. Burrell v. Hackley, 35 Fed. Rep. 833. an admission of the facts alleged1 and a waiver of irregularities. When a plea is overruled the defendant is permitted to answer3 and sometimes the plea is allowed to remain as the answer or part of the answer.4 XVI. DEMURRER.-A demurrer, at law or in equity, is to take advantage of defects appearing upon record.5 Defenses Which Cannot be Set Up in a Plea. Infringement. Korn υ. Wilbusch, 33 Fed. Rep. 50; Matthews v. Lalance Mfg. Co., 18 Blatchf. (U. S.) 84; s. c., 5 Bann. & Ard. Pat. Cas. 319; s. c., 2 Fed. Rep. 232; s. c., 17 Pat, Off. Gaz. 1284. Where the determination of the issues sought to be raised by the plea, required the patents specified in the bill to be examined and passed on by the court, the defendant will be ordered to answer. White v. Lee, 4 Fed. Rep. 916. Every plea should have certificate and affidavit of counsel; but this is waived by demurrer and argument to the merits. Goodyear v. Toby, 6 Blatchf. (U. S.) 130. 1. Wheeler v. McCormick, 8 Blatchf. (U. S.) 267: s. c., 4 Fish. Pat. Cas. 433; Birdseye v. Heilner, 26 Fed. Rep. 147. 2. Goodyear v. Toby, 6 Blatchf. (U. S.) 130. But a replication filed where the plea is bad in substance does not prevent it from being overruled. Matthews v. Lalance etc. Mfg. Co., 18 Blatchf. (U.S.) 84; s. c., 2 Fed. Rep. 232; s. c., 17 Pat. Off. Gaz. 1284; s. c., 5 Bann. & Ard. Pat. Cas. 319. Right to Begin and Close.-If a replication is filed, complainant has right to begin and close. Reissner v. Anness, 3 Bann. & Ard. Pat. Cas. 176; s. c., 13 Pat. Off. Gaz. 870. 3. Wooster v. Blake, 7 Fed. Rep. 816, s. c., 20 Pat. Off. Gaz. 158. The matter litigated by a plea cannot generally be raised again by an Hubbell v. DeLand, 11 Bliss. answer. (U.S.) 383. But the court may permit an answer to be filed upon terms raising the same point. Matthews v. Lalance etc. Mfg. Co., 18 Blatchf. (U. S.) 84. Exception as to Plea in Confession and Avoidance-A plea confessing and avoiding, where the matter in avoidance is decided against the plea, being overruled, and the main facts of the bill admitted by the plea, warrants a a decree for complainant Lilienthal v. Washburn, 8 Fed. Rep. 707. 4. Albright v. Empire Trans. Co., 14 Pat. Off. Gaz. 523. Where a defendant makes a plea part of his answer, he will not be compelled more or otherwise than if he had filed a regular plea. Adams v. Bridgewater Iron Co., 6 Fed. Rep. 179. 5. Laches of complainant can be raised by demurrer. McLaughlin v. People's R. Co., 21 Fed. Rep. 574. Where, in an equity suit, the defendant desires to avail himself of the de Ör fense that the patent is too near its expiration to warrant an injunction. New York Grape Sugar Co. v. Peoria Grape Sugar Co., 21 Fed. Rep. 878. Or that two patents do not interfere with each other. Morris v. Kempshall Mfg. Co., 20 Fed. Rep. 121. that plaintiff had not alleged that defendant had not derived right from a licensee who had power to give such right. Still v. Reading, 4 Woods (U. S.) 345; s. c., 9 Fed. Rep. 40; s. c., 20 Pat. Off. Gaz. 1025. Or that a license was not averred to be properly revoked. White v. Lee, 3 Fed. Rep. 222; Bloomer v. Gilpin, 4 Fish. Pat. Cas. 50. Where profert is made an objection to, it may be taken by demurrer. Bogart v. Hinds, 25 Fed. Rep. 484; s. C., 33 Pat. Off. Gaz. 1268. A demurrer to a bill joining in one action a corporation and its assignee, alleging that the causes of action against the corporation and its assignee are distinct is bad. Gordon v. St. Paul Harvester Works, 23 Fed. Rep. 147. Questions of Pleading.-Questions of pleading must be raised by demurrer. Pellam v. Edelmeyer, 21 Blatchf. (U. S.) 188; Gillespie v. Cummings, 3 Sawy. (U. S.) 259; Hodge v. North Missouri R. Co., 1 Dill. (U. S.) 104; Case v. Redfield, 4 McLean (U. S.) 526; Phillips v. Comstock, 4 McLean (U. S.) 525; Wilder v. McCormick, 2 Blatchf. (U. S.) 31; Peterson Wooden, 3 McLean (U. S.) 248; Stanley v. Whipple, 2 McLean (U. S.) 35; Dobson v. Campbell, 1 Sumn. (U. S.) 319; Tryon v. White, 1 Pet. (C. C.) 96; Evans v. Kremer, 1 Pet. (C. C.) 215; Evans v. Eaton, 1 Pet. (C. C.) 322. V. XV. ANSWER-1. Responsively and as Defense.-All the material allegations of the bill must be answered; but if the answer responds to the bill the defendant is in no default by refusing to answer any part thereof to which he is not specially interrogated;2 and all allegations of defense, which cannot be made at hearing, made.3 { A bill which alleges both joint and several infringement by the defendants, is demurrable. Putnam v. Hollendér, 19 Blatchf. (U. S.) 48. Or to a bill bad for multifariousness. Hayes v. Dayton, 18 Blatchf. (U. S.) 420. A demurrer can be filed to a replica tion where the latter sets up a new defense. Burdell v. Denig, 15 Fed. Rep. 397. A demurrer to a bill entitled to the circuit court act, in chancery sitting, is bad. Sterrick v. Pugsley, i Flipp. (U. S.) 350. A demurrer to a bill which did not allege the location of complainants and which was not sworn to, has been overruled. National Hay Rake Co. v. Harber, 2 W. N. C. (Pa.) 100. Waiver of Right to Demur.-Putting in an answer to the whole bill is a waiver of the right to demur. Adams v. Howard, 20 Blatchf. (U. S.) 38; s. c., 9 Fed. Rep. 347; s. c., 21 Pat. Off. Gaz. 364. To What Demurrer Must Apply.-A demurrer must apply only to the pleading which is bad or it will be overruled. 2 Curt. (U. S.) 97 A demurrer may, where there are special grounds for action, be sustained in part and overruled in part. International Co. v. Maurer, 44 Fed. Rep. 618. But a demurrer should not be filed to a mere surplusage. Stirratt v. Excelsior Mfg. Co., 44 Fed. Rep. 142. A demurrer to a bill for infringement on the ground that there was no invention in the devise patented, will not be sustained unless the case is a very clear one. Blessing v. John Trageser Steam Copper Works, 34 Fed. Rep. 753; Standard Oil Co. v. Southern Pac. R. Co., 42 Fed. Rep. 295. See Judicial Knowledge, infra, But where by judicial knowledge, upon an inspection of the device, the court can see there is no invention, it will sustain a demurrer and dismiss the bill. West v. Rae, 33 Fed. Rep. 45. A demurrer will not lie to a "notice" under the statute of special defenses. Henry v. United States, 22 Ct. of Cl. 75. 1. Perry v. Corning, 6 Blatchf. (U. S.) 134; Jordan v. Wallace, 5 Fish. Pat. Čas. 185; Agawam Co. v. Jordan, 7 Wall. (U. S.) 583. Irresponsive Sworn Answer Not Evidence for Defendant.-An answer under oath which is irresponsive to the bill, is not evidence for the defendant. Sargent v. Larned, 2 Curt. (U. S.) 340. The answer must be on "knowledge, information and Belief," not on knowledge only, if all three are required. Parks v. Bryan, 1 Story (U. S.) 296. A corporation cannot be compelled to answer under oath, but can be made to answer fully where oath is waived. Colgate v. Campagnie Francaise du Telegraphe, 23 Fed. Rep. 82. The answer must be by the party and not by the attorney. Wooster v. Muser, 20 Fed. Rep. 162. And be sworn to, unless the oath is waived, by all the parties professing to answer. Washing Machine Co. v. Young, I Bann. & Ard. Pat. Cas. 362. 2. Brooks v. Bicknell, 3 McLean (U. S.) 250; s. c., 2 Robb Pat. Cas. 118. If the bill requires an answer under oath to certain interrogatories, the rest of the answer is not evidence of facts averred therein. Wren v. Spencer etc. Mfg. Co., 5 Bann. & Ard. Pat. Cas. 61; S. C., 18 Pat. Off. Gaz. 857. Separate answers may, if defendant so desires, be filed to each patent sued on. Kelleher v. Darling, 4 Cliff. (U. S.) 424; s. c., 3 Bann. & Ard. Pat. Cas. 438; s. c., 14 Pat. Off. Gaz. 673. 3. Goodyear v. Providence Rubber Co., 2 Fish. Pat. Cas. 499; s. c., 2 Cliff. (U.S.) 351; Yale etc. Mfg. Co. v. North, 3 Fish. Pat. Cas. 279; s. c., 5 Blatchf. (U. S.) 455; Howes v. Nute, 4 Cliff. (U. S.) 173; S. C., 4 Fish. Pat. Cas. 263; Russell Mfg. Co. v. Mallory, 10 Blatchf (U. S.) 140; s. c., 5 Fish. Pat. Cas. 632; s. c., 2 Pat. Off. Gaz. 495; Jennings v. Pierce, 15 Blatchf. (U. S.) 42; s. C., 3 Bann. & "Ard. Pat. Cas. 361; Wonson v. Peterson, 3 Bann. & Ard. Pat. Cas. 259; s. c., 13 Pat. Off. Gaz. 548; Bragg v. Stockton, 27 Fed. Rep. 509. Clearness of Defense.-The defense must be set up clearly. Puetz v. |