ventor's Claim.2 Every invention is a unit, distinct from every other invention, however similar in purpose or appearance, and except in cases where there is a joinder of inventions a patent covering one does not afford protection to the other. To construe a patent in such a manner that it may apply to either of these separate inventions at the pleasure of the inventor defeats the very object for which the power has been confided to the courts. While the patentee is entitled to the broadest definite interpretation which his language will legitimately bear, and is presumed to claim the invention to its full extent as so defined, the patent, when interpreted, must point out the invention whose protection it secures with a completeness and exactness which distinguish it from every other. Ambiguities and inaccuracies in essential portions of the patent, which cannot be removed by such interpretation, render the patent to that extent inoperative and void. § 739. Rule of Liberal Construction Permits an Interpretation in Accordance with the Real Nature of the Invention unless the Language of the Patent Clearly Forbids it. Where the language of a patent is clear and capable of but one meaning, the duty of the court is fulfilled by interpreting its words and phrases in their proper sense, and defining the invention in accordance with this interpretation.1 If, 2 That a patent cannot be extended by construction to embrace any invention which it does not specifically claim, see Van Camp v. Maryland Pavement Co. (1888), 43 O. G. 884. That Claims are not to be expanded by construction so as to cover more than the patentee first intended, see Couse v. Johnson (1879), 16 O. G. 719 ; 4 Bann. & A. 501. That limited Claims are not to be expanded into general ones by implication or otherwise, see Detmold v. Reeves (1851), 1 Fisher, 127. That the courts will not enlarge Claims by construction, see Burns v. Meyer (1879), 100 U. S. 671; Railway Co. v. Sayles (1878), 97 U. S. 554; 15 That a Claim for the special arrangement of parts must be construed to cover only the special parts and special arrangement, see Buzzell v. Andrews (1885), 25 Fed. Rep. 822; 34 O. G. 830. § 739. That the specification and Claims ought to be construed to mean just what they seem to mean, see Anders v. Gilliland (1880), 19 O. G. 177. That when Claims are clear and ex plicit they cannot be restricted or en as thus defined, the invention is not patentable either for want of novelty, utility, or inventive skill, or on account of previous dedication to the public, the inventor must abide the consequences, procuring an amendment of his patent when it does not correctly represent his actual invention, or relinquishing his claims entirely when what he has invented proves to be not entitled to protection. But when the language is not clear, or is capable of various constructions, recourse to extrinsic facts is often necessary to ascertain the sense in which in this particular case it must be understood.? The most important of these facts is the nature of the actual invention which the patent was intended to secure. This larged by reference to features not mentioned therein nor implied thereby, see Funck v. Doty (1878), 14 O. G. 157. That the patentee is not limited to the literal import of his description, but may depart from it provided he does not change the principle nor make material alterations in its operation, see Grier v. Castle (1883), 17 Fed. Rep. 523; 24 O. G. 1176. 2 That the construction of a patent depends on its words, or where these are ambiguous, on other circumstances, see Evans v. Eaton (1818), 3 Wheaton, 454; 1 Robb, 243. 3 In Van Marter v. Miller (1879), 15 Blatch. 562, Wallace, J.: (563) "In construing a patent, it is first pertinent to ascertain what, in view of the prior state of the art, the inventor has act ually accomplished; and this having been found, such a construction should be given as will secure the actual invention to the patentee, so far as this can be done consistently with giving due effect to the language of the specification and Claim." 4 Bann. & A. 124 (124). In Page v. Ferry (1857), 1 Fisher 298, Wilkins, J.: (302) "The intention of the inventor, so as to effect the object designed, is to govern the con struction of the language he employs. Inventors are not always educated or scientific men. Some most useful inventions have sprung from an illiterate source. Genius is not always blessed with the power of language. Courts look to the manifest design in order to remove any ambiguity arising from the terms employed. But this am biguity must not be such as would perplex an ordinary mechanic in the art to which it applies." In Winans v. Denmead (1853), 15 How. 330, Curtis, J.: (341) “Now, while it is undoubtedly true that the patentee may so restrict his Claim as to cover less than what he invented, or may limit it to one particular form of machine, excluding all other forms though they also embody his invention, yet such an interpretation should not be put upon his Claim if it can fairly be construed otherwise; and this for two reasons: (1) Because the reasonable presumption is that, having a just right to cover and protect his whole invention, he intended to do so, Haworth v. Hardcastle, Web. P. C. 484; (2) Because specifications are to be construed liberally, in accordance with the design of the Constitution and the Patent Laws of the United States to promote the progress of the useful arts, and allow in being known the language of the patent must be construed to correspond with its essential attributes, unless such a construction would do violence to the terms employed. In that event a different interpretation must be given, although the eventual defeat of the patent may be thus ensured. § 740. Nature of the Invention Shown by State of Art at Date of Invention. The nature of the invention attempted to be covered by the patent is sometimes evident upon its inspection or upon an examination of its practical operation. When this is not the case an investigation of the state of the art at the date of the invention may be instituted. ventors to retain to their own use, not anything which is matter of common right, but what they themselves have created." Further, that the patent is to be construed by the nature of the invention, see Steam Gauge and Lantern Co. v. Ham Mfg. Co. (1886), 28 Fed. Rep. 618; Hoff v. Iron Clad Mfg. Co. (1886), 35 O. G. 1230; Fitch v. Bragg (1881), 20 O. G. 1589; 8 Fed. Rep. 588; Washburn & Moen Mfg. Co. v. Haish (1881), 7 Fed. Rep. 906; 10 Bissell, 83; Robinson v. Sutter (1880), 10 Bissell, 100; 19 O. G. 127; 8 Fed. Rep. 828; Whitnum v. Seaman (1880), 5 Bann. & A. 95; 17 O. G. 626; 4 Fed. Rep. 436; Clark v. Kennedy Mfg. Co. (1877), 11 O. G. 67; 14 Blatch. 79; Merrill v. Yeomans (1877), 94 U. S. 568; 11 O. G. 970; Good year Dental Vulcanite Co. v. Davis (1877), 12 O. G. 1; 3 Bann. & A. 115; Bruff v. Ives (1877), 11 O. G. 924; 14 Blatch. 198; Mann v. Bayliss (1876), 10 O. G. 789; Bussey v. Wager (1875), 9 O. G. 300; Glue Co. v. Upton (1874), 4 Clifford, 237; 6 O. G. 837; 1 Bann. & A. 497; Barnes v. Straus (1872), 2 O. G. 62; 9 Blatch. 553; 5 Fisher, 531; McDougal v. Eames (1872), 2 O. G. 87; Taylor v. Garretson (1871), 5 Fisher, 116; 9 Blatch. 156; Coffin &. Every invention is a step Ogden (1869), 7 Blatch. 61; 3 Fisher, 640; Woodman v. Stimpson (1866), 3 Fisher, 98. That a patent will be so construed, if possible, as to protect the entire invention, see Henderson v. Cleveland Co-operative Stove Co. (1877), 2 Bann. & A. 604; 12 O. G. 4; Hamilton v. Ives (1873), 6 Fisher. 244; 3 O. G. 30. That a specification should be construed with reference to the purpose of the invention, see Roberts v. Schreiber (1880), 2 Fed. Rep. 855; 18 O. G. 125; 5 Bann. & A. 491. That a patentee is entitled to such a construction of his patent as will enable it to protect all forms of his invention, though he has described but one, unless he has restricted himself to certain forms in his Claims, see Grier v. Castle (1883), 24 O. G. 1176; 17 Fed. Rep. 523; Winans v. Denmead (1853), 15 How. 330. That the construction given to the patent by the patentee will be sustained, if it is consistent with the language used, see Tondeur v. Stewart (1886), 28 Fed. Rep. 561; 37 O. G. 672; Bradley v. Dull (1884), 19 Fed. Rep. 913; 27 O. G. 625; Klein v. Russell (1873), 91 Wall. 433. § 740. That patents are to be construed in view of the state of the art, forward in the progress of the art to which it belongs, and the character of that step is often best determined by examining the condition of the art immediately before the step was taken and comparing it with the condition to which such step advanced the art. The difference between these must be the precise result of the inventor's act, and when it can be clearly ascertained it affords the safest guide to the exact scope of his invention. The state of the art at the date of the invention may be shown by previous patents, by the processes or instruments then known to the art, or by the testimony of persons acquainted with its general history and development.2 see Grier v. Wilt (1887), 120 U. S. 412; 38 O. G. 1365; Railway Register Mfg. Co. v. Broadway & Seventh Ave. R. R. Co. (1886), 26 Fed. Rep. 522; 34 O. G. 921; Reed v. Chase (1885), 25 Fed. Rep. 94; 33 O. G. 996; Buckingham v. Porter (1884), 10 Sawyer, 289; 36 O. G. 820; 26 Fed. Rep. 759; Jones v. Barker (1882), 22 O. G. 771; 11 Fed. Rep. 597; Sutro v. Moll (1881), 8 Fed. Rep. 909; 19 Blatch. 89; Root v. Lamb (1881), 7 Fed. Rep. 222; 19 O. G. 937; Washburn & Moen Mfg. Co. v. Haish (1880), 10 Bissell, 83; 7 Fed. Rep. 906; Webster Loom Co. v. Higgins (1879), 16 O. G. 675; 15 Blatch. 446; 4 Bann. & A. 88; Van Marter v. Miller (1879), 4 Bann. & A. 124; 15 Blatch. 562; Blaisdell v. Tuffts (1878), 15 O. G. 881; Bruff v. Ives (1877), 11 O. G. 924; 14 Blatch. 198; Clark v. Kennedy Mfg. Co. (1877), 14 Blatch. 79; 11 O. G. 67; Estabook v. Dunbar (1876), 10 O. G. 909; 2 Bann. & A. 427; Salamander Felting Co. v. Haven (1875), 9 O. G. 253; 2 Bann. & A. 164; 3 Dillon, 131; Burden v. Corning (1864), 2 Fisher, 477; Pitts v. Wemple (1855), 1 Bissell, 87; 2 Fisher, 10. That a patent must be construed to claim only what the state of the art shows to be new, see Scott v. Evans (1882), 11 Fed. Rep. 726. That where the scope of the art is limited the Claim must receive a nar row construction, see Adams v. Bellaire Stamping Co. (1886), 28 Fed. Rep. 360; 36 O. G. 567. That the specification will be construed in view of the state of human knowledge and not as intending the impossible, see Tilghman v. Mitchell (1864), 2 Fisher, 518. That a patent is construed by the state of the art at the date of the invention, and the description is limited to what thus appears to be new, see Neacy v. Allis (1882), 22 O. G. 1621; 13 Fed. Rep. 874; Jones v. Barker (1882), 11 Fed. Rep. 597; 22 O. G. 771; Giant Powder Co. v. California Vigorit Powder Co. (1880), 4 Fed. Rep. 720; 18 O. G. 1339; 6 Sawyer, 508. That it is the state of the art at the date of the invention, not the application, which gives its meaning to the patent, see Sprague v. Adriance (1877), 14 O. G. 308; 3 Bann. & A. 124. § 741. Nature of the Invention Shown by Other Acts and Circumstances. The character of the actual invention may also be evidenced by other statements of the inventor concerning its essential attributes. His allegations after the patent has been issued are of little weight, whether they tend to narrow or enlarge the scope of his invention. But the position he assumed before the Patent Office while applying for a patent, the claims he then asserted, the concessions he there made, are all important indications as to the true nature of the idea of means which he embodied in his concrete invention and which he has endeavored to describe and claim in his patent.2 Thus his correspondence with the Patent Office, the application, the amendments filed, the disclaimers offered, the objections raised and answered or avoided, are proper matters for examination by the court.3 Besides these, any other invention, see Giant Powder Co. v. California Vigorit Powder Co. (1880), 6 Sawyer, 508; 18 O. G. 1339; 4 Fed. Rep. 720. That the description in a patent is to be construed in the light of prior patents, and its general terms are to be restricted by them, see Parsons v. Colgate (1882), 15 Fed. Rep. 600; 24 O. G. 203; 21 Blatch. 171. That the patent will be construed in the light of the uncontradicted testimony as to prior devices, in order to ascertain its real scope, see Day v. Combination Rubber Co. (1880), 17 O. G. 1347; 2 Fed. Rep. 570; 5 Bann. & A. 385. § 741. 1 That the Claims may be construed in connection with the testimony of the patentee as to the actual invention, see Matthews v. Iron Clad Mfg. Co. (1888), 124 U. S. 347; 42 O. G. 827. That a patent will not be narrowed from its evident meaning for the reason that the patentee and former owner says that his invention was not as broad as his specification, see Union Paper Bag Mach. Co. v. Pultz & Walkley Co. (1878), 15 Blatch. 160; 15 O. G. 423 ; 3 Bann. & A. 403. 2 That the terms of the application and the proceedings in the Patent Office are to be considered in construing Claims, see Otis Bros. Mfg. Co. v. Crane Bros. Mfg. Co. (1886), 27 Fed. Rep. 550. That a patentee cannot insist that his patent shall be construed to cover matter which he was compelled to abandon in the Patent Office in order to obtain a patent, and the records of the Office may be examined on this question, see Sutter v. Robinson (1886), 119 U. S. 530; 38 O. G. 230. 8 That the meaning of a patent may be ascertained by examining the correspondence of the inventor with the Patent Office during the application, see Goodyear Dental Vulcanite Co. v. Davis (1880), 102 U. S. 222; 19 O. G. 543. That a patent cannot be construed to cover articles which the Commissioner and the patentee agreed were outside it when the patent was issued, and this agreement may be shown by the corre |