patent shall be void if the specification is defective. English decisions, therefore, founded on the assumed reason for the grant of a patent, are not of authority here where the Constitution and laws give other reasons, and omit the one founded on the public benefit to result from the disclosure after the expiration of the privilege. You will therefore not make that a subject of deliberation, for it is not material whether the public can profit by the invention during or after the term of the patent. The true inquiry is whether, in the spirit of the law, the plaintiffs have made such a description of the thing patented as to distinguish it from all others before known, and to enable others skilled in the matter to make, compound, or use it, and to explain the principle and mode of application by which it can be so distinguished from other inventions. If from the patent, specification, drawings, model, and old machine, clear ideas are conveyed to men of mechanical skill in the subject-matter, by which they could make or direct the making of the machine by following the directions given, the specification is good within the act of Congress." 1 Robb, 567 (591).

should fully appear; but still it may be presumed from circumstances entirely to the satisfaction of the jury, which would be sufficient to authorize them to find the fact. As if the parts concealed are so essential and so obviously neces sary to be disclosed that no mechanic skilled in the art could reasonably be expected to understand the subject, so as from the description given to make the machine, it would be difficult to impute the omission of the patentee to a fair motive. But this presumption would seem to be much weakened in a case like the present, where so many practical mechanics have testified that they could not hesitate in supplying the omissions in this specification." 1 Robb, 120 (128).

In Whittemore v. Cutter (1813), 1 Gallison, 429, Story, J.: (435) "It is therefore argued that if the specification be materially defective, or obscurely or so loosely worded that a skilful workman in that particular art could not construct the machine, it is a good defence against the action, although no intentional deception has been practised. And this is beyond all question the doc. trine of the common law; and it is founded in good reason; for the monopoly is granted upon the express condition that the party shall make a full and explicit disclosure, so as to enable the public, at the expiration of his patent, to make and use the invention or improvement in as ample and beneficial a manner as the patentee himself. If, therefore, it be so obscure, loose, and imperfect that this cannot be done, it is defrauding the public of all the consideration upon which the monopoly is granted. And the motive of the party, whether innocent or otherwise, becomes immaterial, because the public mischief remains the same. It is said that the

In Gray v. James (1817), Peters, C. C. 394, Washington, J.: (401) "But if the jury should be of opinion that the specification is materially defective, the objection will not be sufficient to invalidate the plaintiff's patent, unless they should also be satisfied that the concealment of the circumstances not described was intended to deceive the public. What degree of evidence ought to be required to prove such fraudulent intention must rest with the jury to decide. Positive evidence can seldom be expected, nor is it necessary. The law, it is true, requires that such intention

law is the same in the United States, notwithstanding the wording of the sixth section, for there is a great distinction between a concealment of material parts, and a defective and ambiguous description of all the parts; and that in the latter case, although there may be no intentional concealment, yet the patent may be avoided for uncertainty as to the subject-matter of it. There is considerable force in the distinction at first view; and yet, upon more close examination, it will be difficult to support it. What is a defective description but a concealment of some parts necessary to be known in order to present a complete view of the mechan. ism? In the present case the material defects were stated, among other things, to consist in a want of a specific description of the dimensions of the component parts, and of the shapes and position of the various knobs. Were these a concealment of material parts, or a defective and ambiguous disclosure of them? Could the Legislature have intended to pronounce that the concealment of a material spring should not, unless made with design to deceive the public, avoid the patent, and yet that an obscure description of the same spring should at all events avoid it? It would be somewhat hazardous to attempt to sustain such a proposition. It was probably with a view to guard the public against the injury arising from defective specifications that the statute requires the letters-patent to be examined by the attorney general, and certified to be in conformity to the law, before the great

seal is affixed to them. In point of practice, this must unavoidably be a very insufficient security, and the policy of the provision that has changed the common law may be very doubtful. This, however, is a consideration proper before another tribunal. We must administer the law as we find it. And, without going more at large into this point, we think that the manifest intention of the Legislature was, not to allow any defect or concealment in a specification to avoid the patent, unless it arose from an intention to deceive the public. There is no ground, therefore, on which we can support this objection." 1 Robb, 28 (34).

:

In Park v. Little (1813), 3 Wash. 196, Washington, J. (198) "It is true that the thing for which the patent is granted should be truly and fully described in the specification; but if this is done, so as clearly to distinguish it from all other things before known, and so as to enable any person skilled in the art of which it is a branch, or with which it is most nearly connected, to make and use the same, it is sufficient, the matters not disclosed must appear to have been concealed for the purpose of deceiving the public, to invalidate the patent." 1 Robb, 17 (19).

8 That ambiguity in the Description is fatal irrespective of the intent of the inventor, see Blake v. Stafford (1868), 3 Fisher, 294; 6 Blatch. 195; also §§ 969, 970, 972, 1035, 1037 and notes, post.

4 In Ames v. Howard (1833), 1 Sumuer, 482, Story, J.: (485) "The

Constitution of the United States, in giving authority to Congress to grant such patents for a limited period, declares the object to be to promote the progress of science and useful arts, an object as truly national, and meritorious, and well-founded in public policy as any which can possibly be within the scope of national protection. Hence it has always been the course of the American Courts (and it has latterly become that of the English courts also) to construe these patents fairly and liberally, and not to subject them to any overnice and critical refinements. The object is to ascertain what, from the fair sense of the words of the specification, is the nature and extent of the invention claimed by the party; and when the nature and extent of that claim are apparent, not to fritter away his rights upon formal or subtile objections of a purely technical character. Now let us see what is the invention, as claimed by the plaintiff in the specification in this case. I agree that if he has left it wholly ambiguous and uncertain, so loosely defined, and so inaccurately expressed that the court cannot, upon a fair interpretation of the words and without resorting to mere vague conjecture of intention, gather what it is, then the patent is void for this defect. But if the court can clearly see what is the nature and extent of the claim, by a reasonable use of the means of interpretation of the language used, then the plaintiff is entitled to the benefit of it, however imperfectly and inartificially he may have expressed himself. And for this purpose we are not to single out particular phrases standing alone, but to

take the whole in connection." 1 Robb, 689 (692).

That ambiguity is not fatal unless the Description is rendered unintelligible, see Swift v. Whisen (1867), 2 Bond, 115; 3 Fisher, 343; Judson v. Moore (1860), 1 Fisher, 544; 1 Bond, 285.

That ambiguity may be removed by the oath or other parts of the applica tion, see Pettibone v. Derringer (1818), 4 Wash. 215; 1 Robb, 152.

That if the Description has no apparent meaning when construed by the court, the patent is void, see Emerson v. Hogg (1845), 2 Blatch. 1.

That any ambiguity, which is suffi cient to perplex persons skilled in the art, is fatal, see Page v. Ferry (1857), 1 Fisher, 298.

See also §§ 969, 970, 1034, 1035 and notes, post.

That the Description must so disclose the invention that no further exercise of inventive skill is necessary in order to practise it, see Neilson v. Harford (1841), 1 Web. 331; Morgan v. Seaward (1836), 1 Web. 170; 2 Abb. P. C. 262; R. v. Arkwright (1785), 1 Web. 64; 1 Abb. P. C. 29.

That no further experiment must be needed to practise the invention, see Lockwood v. Faber (1886), 27 Fed. Rep. 63; Simpson v. Holliday (1865), 12 L. T. Rep. N. s. 99; Muntz v. Foster (1844), 2 Web. 96; McNamara v. Hulse (1842), 2 Web. 128; 1 Coll. 477 ; Neilson v. Harford (1841), 1 Web. 331; R. v. Wheeler (1819), 2 B. & Ald. 345; 1 Abb. P. C. 317; R. v. Arkwright (1785), 1 Web. 64; 1 Abb. P. C. 29.