it, or published a printed description of it, before its invention by the patentee or his assignor, the defence of want of legal novelty as well as that of prior invention is appropriate. But if the prior inventor has not practised his invention, or patented or published it before the patentee or his assignor performed the inventive act, or if the patentee or his assignor first conceived the idea but through his want of diligence in reduction has given a later conceiver and prompt reducer the superior right to the invention, the defence of want of legal novelty cannot be sustained. A patented invention is new, within the meaning of the law, unless before the date of its complete conception by the patentee or his assignor it had been known or used in this country, or had been patented or described in a printed publication either at home or abroad.1 A prior use, in order to create a want of novelty, must consist in the practical employment of the identical invention for business purposes in the United States, in such a manner as to render the knowledge of the invention accessible to the public before and until the date of its conception by the patentee or his assignor.2 A prior patent constitutes a want of novelty when it was issued to the public before the date of the inventive act in question, and contains so full and complete a description and claim of the identical invention as to enable any person skilled in the arts to practise it without further invention of his own.3 A prior publication proves a want of novelty when in its printed text, distributed to the public before the patentee or his assignor conceived the idea of the invention, the essential characteristics of the art or article are so disclosed that those skilled in the art can by the guidance of the publication alone construct it and apply it to practical use. It is to be remembered that these three conditions under which novelty is wanting are not merely evidence that the invention is not legally new, but are facts which cause it to be legally old. Novelty is a legal attribute consisting in

§ 963. 1 For the nature of legal novelty as distinguished from actual novelty, see §§ 113, 123, 222-228, 315, 316, and notes, ante.

2 As to prior use, see §§ 317-324, and notes, ante.

3 As to prior patent, see §§ 331-337, and notes, ante.

As to prior publication, see §§ 325330, and notes, ante.

the absence of these three conditions, and when the existence of either is established by sufficient proof it is a conclusion of law, and not an inference of fact, that the invention is not new. Thus the defence of want of novelty may logically be subdivided into the three defences of prior use, prior patent, and prior publication, each of which may be urged without the others, and if found true forms a complete bar to the action.

§ 964. Sixth Defence: Denial of the Utility of the Patented Art or Instrument.

The sixth defence consists in a denial of the utility of the invention. An invention is useful within the meaning of the law if it is available for any use which on the whole is beneficial to the public. An utterly frivolous and worthless art or article has no utility. An invention capable of beneficial use, but so dangerous or disastrous to its employers as to be necessarily productive of more injury than advantage, is not useful. An invention whose practice may promote the interest of the individual user, but is inevitably prejudicial to the public, also wants utility. This defence is thus equivalent to an averment that the invention is incapable of any beneficial use, or that its use involves a greater loss than gain to its employers, or that its use is detrimental to the public.2 Defendants who have actually practised the invention, especially those who have endeavored to induce the public to participate in its results by purchasing the fruits of their infringements, are estopped from urging it on their own behalf when sued for their wrong-doing.3

§ 964. 1 For the nature and necessity of utility, see §§ 338-343, and notes, ante.

2 That the want of utility is a perfect defence, see Bliss v. City of Brooklyn (1873), 6 Fisher, 289; 3 O. G. 269; 10 Blatch. 521.

That the manifest frivolity of the invention patented is a good defence, see Wilson v. Jones (1854), 3 Blatch. 227.

That an immoral or dangerous in

vention may lack utility, see § 340, and notes, ante.

8 That to sustain a defence of want of utility the evidence must show that the invention is utterly worthless, and if the defendant has used it, that fact is a strong argument in favor of utility, see Kearney v. Lehigh Valley R. Co. (1887), 32 Fed. Rep. 320.

That want of utility avails little as a defence for parties who used the in

§ 965. Seventh Defence: Abandonment of the Invention to the

Public.

The seventh defence consists in an averment that the invention was abandoned to the public before the commission of the acts of which the defendant is accused. In this defence there is no question of incomplete and abandoned experiments performed by the patentee or his assignor while endeavoring to perfect the invention, or by rival inventors in their attempts to reach the same result. Evidence of such experiments may be admissible under the defences of prior invention and of prior use, but of themselves they constitute no bar to an action on the patent, and especially have no relation to this defence of abandonment. Abandonment is synonymous with dedication to the public. It assumes that the invention is complete and practically operative, and it occurs only where the invention, being in that condition, is intentionally and unreservedly surrendered to the public by its lawful owner.1 This defence is, therefore, proper when such an intentional surrender has been made, either by the inventor or the patentee or any subsequent owner of the patent. A public use or sale of the invention, by the inventor or with his consent, for more than two years before his application for a patent, is one form of surrender.2 Any other conduct of his or of the owner of the patent, which unequivocally manifests the same intention, is also an abandonment of the invention. Such conduct may consist either in acts or declarations of the inventor before his application, or in describing and not claiming the invention in his application, or in disclaiming it in connection

vention, see Phillips v. Carroll (1885), 23 Fed. Rep. 249; 31 O. G. 265; Cook v. Ernest (1872), 2 O. G. 89; 5 Fisher, 396; Vance v. Campbell (1859), 1 Fisher, 483.

That a defendant using an entire process is estopped to claim that any part of it is injurious, see Whitney v. Mowry (1870), 4 Fisher, 207.

That the defendant is estopped from denying the utility of the invention after having made and sold large quan

tities of it, and especially after advertising that the new invention had revolutionized the trade, see Robertson v. Garrett (1873), 6 Fisher, 278; 10 Blatch. 490.

§ 965. 1 As to the nature of abandonment, and its distinction from abandoned experiments and abandoned inventions, see § 346 and notes, ante.

2 As to abandonment by public use or sale, see §§ 354-360, and notes, ante.

with his application or his patent, or in words, actions, or omissions of the owner of the patent after the patent has been granted. This defence has sometimes been subdivided into two: (1) Abandonment by public use or sale; (2) Abandonment by conduct other than public use or sale. Between these two there is an important distinction which is well recognized in the forms of pleading and in the rules of evidence. A public use or sale is not simply an act from which an intention to abandon may be inferred, but it is conclusive evidence of that intention; and when such use or sale is proved there is no room for any further question as to the dedication of the invention to the public. Conduct other than public use or sale is merely a fact from which an intention to abandon may be inferred, but affords no conclusive presumption of such intention and may be rebutted by any evidence affording a contrary indication. This distinction in practical effect has led certain jurists of great authority to separate these two defences from each other, and to treat them as if resting upon different foundations.5 The doctrine which underlies them is nevertheless identical, as is apparent from the definitions given by the courts to the terms " public use and sale," each of which is limited to cases where the use or sale involves a voluntary and intentional surrender by the inventor of all control over the invention, neither an experimental use, however public, nor any sale restricted by conditions which the inventor can enforce against the property in the invention sold, falling within such definitions. This seventh defence.

8 As to abandonment by general conduct, see §§ 350-353, and notes, ante.

That except in cases of public use or sale, the presumption of an intention to abandon may be rebutted, see §§ 347, 348, and notes, ante.

In Jones v. Sewall (1873), 3 O. G. 630, Clifford, J.: (637)" Persons charged with the infringement of letters-patent may set up as a defence that the inventor suffered the invention to be in public use and on sale more than two years before he applied for a patent; and

they may also set up as a distinct de

fence, even in the same answer, that the inventor, before he applied for a patent, abandoned the invention to the public; but these two defences ought not to be blended in the same allegation, as they depend in many respects upon very different principles." 6 Fisher, 343 (365); 3 Clifford, 563 (589).

6 That public use and sale are not abandonment except when unequivocal, unrestricted, and with the consent of the inventor, see §§ 354-360, and notes, ante.

completes the group of those which attack the merits of the invention and deny the right of the inventor or the owner of the patent to be protected in its exclusive use."

§ 966. Eighth Defence: Denial of the Grant of the Alleged Let

ters-Patent.

The eighth defence, or the first one of that group which attacks the letters-patent as distinguished from the invention, consists in a denial that the patent described in the declaration was ever granted by the government. This defence is proper when the alleged invention never has been patented or when the patent which protects it is not correctly set forth by the declaration. It simply raises an issue as to the existence of the document on which the plaintiff has based his suit, and is equivalent to the plea of nul tiel record at the common law. Any material variance between the actual patent and the statement of its tenor and effect in the declaration will support this defence, and unless cured by amendment will defeat the action.

7 That the use of an invention without the consent of the inventor, pending his application, is no defence against the patent, see Dental Vulcanite Co. v. Wetherbee (1866), 3 Fisher, 87; 2 Clifford, 555.

That the defence of public use and sale more than two years "before the invention" is not known to our law, see Kelleher v. Darling (1878), 14 O. G. 673; 4 Clifford, 424; 3 Bann. & A. 438.

That under the defence of two years' public use, the defence of prior use cannot be made, nor is it sustained by evidence of a prior patent without the plaintiff's knowledge over two years before, see Myers v. Busby (1887), 32 Fed. Rep. 670; Parks v. Booth (1880), 102 U. S. 96; 17 O. G. 1089.

That in an action brought after the act of 1837, ("two years") on a patent granted before it, public use prior to the application is a good defence, see

Winans v. New York & Harlem R. R.
Co. (1855), 4 Fisher, 1.

That an application substituted at the instance of the Patent Office for one already filed dates from the filing of the former application as to the question of public use, see International Tooth Crown Co. v. Richmond (1887), 30 Fed. Rep. 775; 39 O.G. 1550.

N. B. In this seventh defence no notice is taken of the public use and sale "without the consent" of the inventor, which seems to be now recognized as a defence under the present statutes. That defence may perhaps rest indirectly on the doctrine of estoppel, but it is certainly not a simple dedication to the public. For a consideration of this subject, see §§ 357, 390, and notes, ante. § 966. As to the averment of the patent in the declaration, see § 950 and notes, ante.