29. Penalties provided in certain cases. The fifth section of the act of 1842 provides " that if any person or persons shall paint, or print, or mould, cast, carve, or engrave, or stamp, upon any thing made, used, or sold by him, for the sole making or selling of which he bath not or shall not have obtained letters patent, the name or any imitation of the name of any other person who bath or shall have obtained letters patent for the sole making and vending of such thing, without consent of such patentee or his as signs or legal representatives ; or if any per son upon any such thing, not having been purchased from the patentee or some person who purchased it from or under such pat entee, or not having the license or consent of such patentee or his assigns or legal representatives, shall write, paint, print, mould, cast, carve, engrave, stamp, or other, wiss make or affix, the word patent,' or the words letters patent,' or the word patentee,' or any word or words of like kind, meaning or import, with the view or intent of imi tating or counterfeiting the stamp, mark, or other device of the patentee ; or shall affix the same, or any word, stamp, or device of like import, on any unpatented article, for the purpose of deceiving the public, he, she, or they so• offending shall be liable for such offence to ,a penalty of not less than one hundred dollars, with costs, to be recovered by action in any of the circuit courts of the United States, or in any of the district courts of the United States having the powers and jurisdiction of a circuit court. One-half of such penalty so recovered shall be paid to the patent•fund, and the other half to any person who shall sue for the same." 30. 'The thirteenth section of the act of 1861 declares that in all cases where an article is made or vended by any person under the protection of letters patent, it shall be the duty of such person to give sufficient notice to the public that said article is so patented, either by fixing thereon the word " patented," together with the day and year the patent was granted, or when, from the character of the article patented, that may be impracticable, by enveloping one or more of the aaid articles, and affixing a label to the package, or otherwise attaching thereto a label, on which the notice, with the date, is printed ; on failure of which, in any mit for the infringement of letters patent by the party failing so to mark the article the right to which la infringed upon, no damage shall be recovered by the plaintiff, except on proof that the defendant was duly notified of the infringement, and continued after such notice to make or vend the article patented.
• The act of congress of Feb. 28, 1839, 5 U. S. Stat. at Large, 322, establishes a five years limitation of suite or prosecutions for a penalty under the laws of the United States. The penalty of not less than one hundred dol lars, imposed by the act, is a penalty of one hun dred dollars and no more. 2 Curt. C.C. 502.
A similar statute--that of 5 & 6 Will. IV.
c. 83—exists in England, for observations upon which see Hindmarch, Patents, 366. It has been decided under that statute that where there has been an unauthorized use of the word " patent" it must be proved that the word was used with a view of imitating or counterfeiting the stamp of the patentee, and that it is no defence that the patented article imitated was not a new manufacture, the grant of the patent being conclusive on the defendant. 3 Hurlst. & N. Exch. 802.
31. Of infringements. The criterion of infringement is substantial identity of con struction or operation. Mere changes of form, proportion, or position, or substitution of mechanical equivalents, will be infringe ments, unless they involve a substantial difference of construction, operation, or effect. 3 McLean, C. C. 250, 432 ; 1 Wash. C. C. 108 ; 15 How. 62 ; 1 Curt. C. C. 279 ; 1 McAll. C. C. 48. As a general rule, when ever the defendant has incorporated in his structure the substance of what the plaintiff has invented and properly claimed, he is responsible to the latter. Burr vs. Duryea, 1 Wallace, 531.
Where the patent is for a new combination of machines to produce certain effects, it is no infringement to use any of the machines separately, if the whole combination is not used. 1 Mas. C. C. 447 ; 2 id. 112 ; 1 Pet.
C. C. 322 ; 1 Stor. C. C. 568 ; 2 id. 190 ; 16 Pet. 336 ; 3 McLean, C. C. 427 ; 4 id. 70 ; 6 id. 539 ; 14 How. 219 ; 24 Vt. 66 ; 1 Black, 427 ; 1 Wallace, 78. But it is an infringe ment to use one of several improvements claimed, or to use a substantial part of the invention, although with some modification or even improvement of form or apparatus.
2 Mas. C. C. 112 ; 1 Stor. C. C. 273. Where the patent describes and claims a machine, it cannot be construed to be for a process or function, so as to make all other machines infringements which perform the same func tion ; and no infringement will in such case take place where the practical manner of giving effect to the principle is by a different mechanical structure and mechanical action. 15 How. 252. If the patentee is the inventor of a device, he may treat as infringers all who make a similar device operating on the Berne principle and performing the same functions by analogoue means or equivalent combinations, although thc infringing ma chine may be an improvement of the original and patentable as such. But if the inven tion claimed is itself but an improvement on a known machine, by a mere change of form or combination of parts, it will not be an infringement to improve the original machine by the use of a different form or combir.a tion of parts performing the same functions The doctrine of equivalents does not in such case apply, unless the subsequent improve ments are mere colorable invasions of the first. 20 How. 405.
A sale of the thing patented to an agent of the patentee, employed by him to mako the purchase on account of the patentee, is not per se an infringement, although, accom panied by other circumstances, it may be evi dence of infringement. 1 Curt. C. C. 260.
The making of a patented machine for philosophical experiment only, and not fox use or sale, has been held to be no infringe ment, 1 Gall. C. C. 429, 485 ; hut a use with a view to an experiment to test its value is an infringement. 4 Wash. C. C. 580. The sale of the articles produced by a patented machine or process la not an infringement, 3 McLean, C. C. 295 ; 4 How. 709 ; nor is the bond fide purchase of patented articles from an infringing manufacturer. 10 Wheat. 359. As to infringement by a railroad cor poration, where its road was worked and ite stock owned by a connecting road, see 17 How. 30. Ignorance by the infringer of the existence of the patent infringed is no defence, but may mitigate damages. 11 How. 587.