in the Description, and others in the drawings or models referred to in the Description, does not satisfy the requirements of this rule. The written Description must be complete in itself, although its language may be illustrated and applied by means of a model or the drawings which accompany it. Whatever features of the invention are indispensable to its performance of the functions which it was intended to discharge are to be described in words as accurately as the nature of the case admits; while features not thus indispensable, although in the inventor's mind inextricably connected with the others, may safely be omitted. Hence details of shape, size, quality, proportion, arrangement, and materials require delineation when essential to the operation of the art or instrument described, but otherwise are superfluous except so far as their mention may become necessary in order to set forth its essential characteristics. Besides this delineation of the parts of the invention and their mutual relations, the state of the art to which it belongs must be sufficiently de Rep. 269; 19 Blatch. 294; 19 O. G. 1705; St. Louis Stamping Co. v. Quinby (1879), 4 Bann. & A. 192; 16 O. G. 135. That the theory on which the invention operates need not be explained, see Eames v. Andrews (1887), 122 U. S. 40; 39 O. G. 1319. 8 That it is not enough that the invention appears in the drawings, -it must also appear in the written Description and Claim, see Gunn v. Savage (1887), 30 Fed. Rep. 366; Roemer v. Neumann (1885), 26 Fed. Rep. 102; Tinker v. Wilber Eureka Mower & Reaper Mfg. Co. (1880), 1 Fed. Rep. 138; 5 Bann. & A. 92; Ex parte Fox (1812), 1 Web. 431; 1 Abb. P. C. 185. Contra, Poupard v. Fardell (1869), 18 W. R. 127; Brunton v. Hawkes (1820), 1 Carp. P. C. 410; 1 Abb. P. C. 336. That drawings may show the form and position of parts of the invention where the Description fails to do so, see Banker v. Bostwick (1880), 18 O. G. 61; 3 Fed. Rep. 517; 5 Bann. & A. 463. That drawings cannot supply the place of a written Description to such an extent that a Claim can be construed to cover matter indicated only by the drawings, see Gunn v. Savage (1887), 30 Fed. Rep. 366. That a model showing the invention cannot supply the place of a written Description, see Barry v. Gugenheim (1872), 1 O. G. 382; 5 Fisher, 452. 4 That the failure to describe an essential element renders the patent useless to the public and void, see Carr v. Rice (1856), 1 Fisher, 198. That the means described must be the essential necessary means, not mere accidental adjuncts, see Russell v. Dodge (1876), 93 U. S. 460; 11 O. G. 151. That a failure to describe an element embraced in the inventor's conception of his invention, but still without which the new machine will work, is not fatal to the patent, see Carr v. Rice (1856), 1 Fisher, 198. 75 scribed to show its real place in the art, and to disclose the precise points in which it differs from all inventions previously known, thus distinguishing the new matter, to be covered by the patent, from the old which is already in the possession of the public. When several inventions are joined in one application, the same particularity of description is necessary in regard to each; and where the invention is generic, at least one species of the genus must be delineated in the manner here prescribed. § 485. The Description must Disclose the Manner of Making the Invention. The manner of making the invention is the method by which the idea of means conceived by the inventor is reduced to practice. While this idea, which is the principle of the invention, is a unit and invariable, the modes of its embodiment in the concrete invention may be numerous and, in appearance, very different from each other. The applicant is not required to describe all possible forms in which this principle may be reduced to practice, or even all such forms as he may have himself adopted. These belong to the skill of the mechanic, not the inventor; and having one embodiment before them, the public are presumed to be able to construct such others as they may desire. But one mode of reducing the idea to practical utility must be described, and this must be the best one known to the inventor, since to withhold, for his own use or that of his licensees, a better form than that which he bestows upon the public would be a fraud upon them and render the patent void. This description of the manner of That the Description must distinguish the new from the old, see Grier v. Castle (1883), 17 Fed. Rep. 523; 24 O. G. 1176; Sawyer v. Miller (1882), 12 Fed. Rep. 725; 4 Woods, 472; Phillips v. Page (1860), 24 How. 164; Teese v. Phelps (1855), 1 McAllister, 48; Dangerfield v. Jones (1865), 13 L. T. Rep. N. s. 142; Newall v. Elliott (1864), 10 Jur. N. s. 954; Holmes v. London & N. W. R. R. Co. (1852), Macrory, P. C. 13; Crane v. Price (1842), 4 M. & G. 580; 1 Web. That the specification must describe making must embrace such a statement of the idea or principle of the invention, and of its application to the materials employed in the practice of the concrete art or the construction of the concrete instrument, that the public, following its directions, may produce from it alone a practically operative invention, performing in the best method known to the inventor the functions which it was intended to discharge.2 Abstract or theoretical principles, however, being mere truths of science or speculative methods of accounting for results, need not be mentioned. The inventor himself is not required to understand them, nor is an acquaintance with them necessary to enable the public to reap the entire benefits of his invention. § 486. The Description must Disclose the Mode of Use of the Invention. The modes of putting an invention to practical use are also often numerous and varied. They belong to the mechanical rather than the inventive side of the invention, although some mode of use must inevitably be contemplated by the inventor while employed in the development of his idea of means, and must, for the same reasons, be stated to the public in order that their knowledge of the invention, as a practically operative art or instrument, may be complete. the best mode of applying the principle of the invention, see Grier v. Castle (1883), 17 Fed. Rep. 523; 24 O. G. 1176. That to conceal the best mode for the benefit of the inventor and his licensees avoids the patent, see Dyson v. Danforth (1865), 4 Fisher, 133. 2 That the Description is sufficient if, from it alone, a competent mechanic can construct the invention, see Wayne v. Holmes (1856), 2 Fisher, 20; 1 Bond, 27. That the statement in the Description of each different method of doing a thing must be so clear that it can be done in each way by those skilled in the art, and if any such way is vaguely stated it must be erased, see Ex parte Howe (1883), 24 O. G. 1090. But having ex 8 That the scientific principle need not be stated, see Eames v. Andrews (1887), 122 U. S. 40; 39 O. G. 1319; Andrews . Cross (1881), 19 O. G. 1705; 8 Fed. Rep. 269; 19 Blatch. 294; St. Louis Stamping Co. v. Quinby (1879), 4 Bann. & A. 192; 16 O. G. 135; Woodward v. Dinsmore (1870), 4 Fisher, 163. That the reason given by the inventor for the operation of his invention is not conclusive, see Stow v. Chicago (1877), 3 Bann. & A. 83; 8 Bissell, 47. § 486. That the Description must disclose a method of putting the inven tion to practical use, see American Hide & Leather Splitting & Dressing Mach. Co. v. American Tool & Mach. Co. (1870), 4 Fisher, 284; Holmes, 503; plained one mode, all other possible modes are assumed to be suggested by it, unless they depend upon the further exercise of inventive skill, in which case they become new and separate inventions. The mode explained must be the best within the knowledge of the applicant; and must be described, not by asserting that a given result can be obtained by using the invention, but by prescribing certain fixed and definite rules of action by following which the given result will be accomplished.1 § 487. The Description to be Confined to these Three Points. To these three subjects the Description ought to be confined. Whatever matters of narration or assertion pass beyond these limits are surplusage, and if they do not render the delineation fatally ambiguous, are at least unnecessary and objectionable. Especially is this true of all expressions praising the art or instrument described, and disparaging competing inventions. The sole object of the Description is to confer knowledge upon the public concerning the intrinsic character of the new device or process and the mode of making it available in practice; and no argument as to its merits, either actual or comparative, can be appropriate in such an instrument.1 Pitts v. Wemple (1855), 2 Fisher, 10; 1 Bissell, 87; Felton v. Graves (1829), 3 C. & P. 611; 1 Abb. P. C. 416; R. *. Wheeler (1819), 2 B. & Ald. 345; 1 Abb. P. C. 317. 2 That having described one mode others need not be mentioned, see Pike v. Potter (1859), 3 Fisher, 55; Derosne v. Fairie (1835), 1 Web. 154; 2 Abb. P. C. 78. That the mode described must be the best mode known to the inventor, see Lorillard v. McDowell (1877), 11 O. G. 640; 2 Bann. & A. 531; 13 Phila. 461. That the patent is valid if the inven. tion serves any use, though it will not fulfil all the uses claimed for it in the patent, see Phillips v. Risser (1885), 26 Fed. Rep. 308. That the Description must not state merely a result but a mode of at taining it, see Burrall v. Rumsey (1877), 13 0. G. 123. § 487. 1 In Aultman v. Holley (1873), 11 Blatch. 317, Woodruff, J.: (325) "The object of a specification is to describe the thing invented, so as to enable a mechanic of ordinary skill to construct it and apply it to practical use; and the Claim declares what the patentee claims as his invention. Beyond this, all essays eulogistic of its utility, and assertions of its capacity, are immaterial and useless." 6 Fisher, 534 (543); 5 O. G. 3 (7). In Ex parte Williams (1872), 1 0. G. 225, Leggett, Com.: (226) “It is proper and desirable that an applicant should briefly, and in a well-condensed form, set forth clearly the present state of the art to which his invention relates; but in doing so he should not ask the § 488. The Description is Sufficient if Sufficient for Persons Skilled in the Art. The language and the methods of statement employed in the description of these three subjects must be such as to place the invention fully in the possession of the public. To render an invention accessible to the public, it is not necessary that it should be so described as to be understood by all the individuals of whom the public is composed. Probably no implement, however simple and however long in use, can be comprehended and applied in practice without some previous knowledge, on the part of him who uses it, as to the end which it is designed to accomplish and the general modes in which such ends must be attained. Every invention is a single step forward in the progress of the industrial arts, and cannot be intelligible except to those who are familiar with the steps already taken and with the object which this new advance is intended to subserve. It would be impossible as well as useless for the inventor, in his application for a patent, to furnish to the general public such a complete knowledge of all past achievements in the arts as would enable them to understand the precise place occupied by his invention, and thus perceive its character, its method of construction, and its mode of use. Each of these arts has its especial votaries, men whose lives are spent in acquiring information concerning the appliances which relate to their own industry, and in putting them in practical operation both for their personal and the public good. The possession of an invention by these artisans is its possession by the public for all beneficial purposes, and the inventor who renders it accessible to them makes it as available to the community at large as, in the nature of things, it could ever be. It is to these persons, skilled in the art to which the invention appertains, that the Description of it in the specification is addressed.1 Office to indorse his claim to superiority over other inventions by name, nor to disparage patents granted to others. A discussion of the merits or demerits of other patents or inventions in the body of a specification is improper, and should not be indulged by the Office. While The inventor has a right to such a discussion may be proper in an argument, it is out of place in a specification. A specification should be descriptive, not argumentative." § 488. In Plimpton v. Malcolmson (1876), L. R. 3 Ch. 531, Jessel, M. R.: (568) "Now what is the meaning of it |