of the complainants for the sum of $9,120.94, being the gains and profits made by the respondents, as ascertained by the master. Both parties appeal to this court. Eight errors are assigned by the respondents, two of which only will be examined: (1) That the court erred in holding that there was invention in using two deflecting plates when the use of one was well known. (2) That the court erred in holding that the respondents infringed the letters patent granted to the complainants. Viewed in the light of the disclaimer, it is 193] clear that the first claim of the patent is for the employment or use of two deflecting plates, one being placed on each side of the saw, for the purpose of preventing the sawed stuff from bearing against the sides of the saw, and to allow a thin veneer saw to be stiffened by the plate employed or used for that purpose; and it is equally clear that the employment or use of one deflecting plate for the purpose was well known and in public use long before the original patentees in this case applied for a patent. Conclusive evidence to support that proposition is found in the disclaimer filed by the complainants pending the suit, in addition to the other evidence in the case, which is abundantly sufficient to establish the proposition, even without the disclaimer. Authority to make such a disclaimer is beyond question, if it be made in writing and is duly attested and recorded in the Patent Office. When so made, attested and recorded, it becomes a part of the original specification to the extent of the interest of those who make it; but the provision is that it shall not affect any action pending at the time of its being filed, except so far as may relate to the question of unreasonable neglect or delay in filing it. 16 Stat. at L., 206, R. S., sec. 4917. Pending suits may proceed, but the disclaimer, when recorded, becomes a part of the original specification, and must be taken into account in construing the patent, and in ascertaining the rights of the parties to the suit, unless it appears that the effect of the disclaimer is to en- | large the nature of the invention, and prejudice the rights of the respondents. Perry v. Skinner, 1 Web. Pat. Cas., 253; Ralston v. Smith, 9 C. B. (N. S.), 117; S. C., 11 C. B. (N. S.), 471; Smith v. Nichols, 21 Wall., 117, 22 L. ed. 567. Where the effect of the disclaimer is to diminish the claims of the patent without prejudicing the rights of the respondent, the suit may proceed, notwithstanding the disclaimer; it being held that the disclaimer, under such circumstances, does not affect the pending suit, except to limit and qualify the claims of the patent, and in respect to the question of unreasonable neglect or delay in filing the same. Unreasonable delay not having been suggested, the only effect of the disclaimer in such a case is to limit the nature of the invention secured by the patent, and to diminish the claims of the patent 194] as set forth in the specification. Guyon 1. Serrell, 1 Blatchf., 245; Hall v. Wiles, 2 Blatchf., 198. claims of the specification. 16 Stat. at L.. 206; Seed v. Higgins, 8 El. & Bl., 767; Higgins v. Seed, 8 El. & Bl., 771; O'Reilly v. Morse, 15 How., 121; Taylor v. Archer, 8 Blatchf., 317. Tested by these considerations, it is clear that the first claim of the patent is for the employment or use of two deflecting plates, one placed on each side of the saw, for the purposes therein set forth and described, Circular plates attached to circular saws, secured by rivets or screws for the purpose of strengthening the central portion of the saw-plate, and sometimes called stiffening plates, are old devices which have been known to the operators of the circular saw ever since the circular saw came into general use for sawing shingles, laths and clapboards. Nor is any argument necessary to show that the employment of one deflecting plate covering the upper part of the stiffening plate on the same side of the circular saw is old, as that is proved by the evidence, conceded in argument, and alleged in the disclaimer filed by the complainants. Concede that; and still it is insisted by the complainants that they employ or use two deflecting plates, one placed on each side of the saw, and that the employment or use of the additional deflecting plate on the opposite side of the saw is a new and useful improvement in the operation of the machine, for which the patentees, whom they represent, were justly entitled to the patent set forth in the bill of complaint. Operators of machines for sawing lumber, whether with circular or vertical saws, have long known that some means were useful, if not absolutely necessary. to spread the two parts of the lumber behind the saw, so as to prevent the lumber as sawed from binding against the two faces of the saw to such an extent as to endanger the saw and impede the progress of the work without an increase of the motive power. Wedges, in early times. were used by the operator to accomplish the object, and various other devices were employed before the *de- 195 flecting plate came into use, which, it seems, has had the effect to supersede all other devices previously known to effect the described function. Such machines for sawing lumber, constructed with one deflecting plate, were well known and in general use years before the patentees in this case made their application for a patent; and the evidence satisfies the court that for most purposes the machine will operate as well and as successfully with one deflecting plate as with two. Two deflecting plates may be better than one, where it is desired to split thin stuff into two parts of equal thickness, as in that case the saw kerf may be enlarged by deflecting the stuff on each side of the saw. Grant that two such plates are in certain cases better than one used alone, still the question arises whether it involves any invention to add the second plate to a machine already constructed with one plate. Beyond doubt, every operator who had used a machine having one deflecting plate knew full well what the function was that the deflecting plate was designed to accomplish, and the reasons for placing it at the side of the saw are obvious to the understanding of every one who ever witnessed the operation of a circular saw. Ordinary mechanics know how to use bolts, rivets and screws, and it is obvious that any one knowing how to use such devices Invention or discovery is the requirement which constitutes the foundation of the right to obtain a patent; and it was decided by this would know how to arrange a deflecting plate | *in this or any foreign country, and must [197 at one side of a circular saw which had such a not have been in public use or on sale for more device properly arranged on the other side, it than two years prior to the application for the being conceded that both deflecting plates are patent. 16 Stat. at L., 201; Collar Co. v. Van constructed and arranged precisely alike, except Dusen, 23 Wall., 563, 23 L. ed., 133. that one is placed on one side of the saw and the other on the opposite side. Both are attached to the frame in the same manner; nor is it shown, either in the specification or draw-court, more than a quarter of a century ago, ings, that there is anything peculiar in the means employed for arranging the deflecting plates at the sides of the saw, or in attaching the same to the frame. Both are alike, except that the outer end of the one on the same side as the strengthening plate projects further from the saw than the inner end, and that the other is rather smaller in diameter, and that the ends project about an equal distance from the saw. Expert witnesses were examined upon the point, whether it required invention to attach a 196] second deflecting plate to such a *machine; and one of the most intelligent and learned of his class testified to the effect that the deflecting plate on one side of the complainant's machine performs precisely the same duty as the plate upon the other side of the saw, and that it required no invention to apply a second plate in such a case to perform exactly the same duty as the one previously applied on the opposite side of the saw; that such second application is a mere duplication of the first; and he supports his conclusion by apt examples, which are both persuasive and convincing. Persons seeking redress for the unlawful use of letters patent must allege and prove that they, or those under whom they claim, are the original and first inventors of the alleged improvement, and that the letters patent have been infringed by the party against whom the suit is brought. Prima facie support to the first requirement is derived from the patent, if it is introduced in evidence and is in due form, provided the alleged improvement is one which in its nature is patentable. Evidence to overcome that presumption, however, is always admissible, if due notice is given by the opposite party, as required by law; and the question is now well settled, that the question whether the alleged improvement is or is not patentable, is, in an equity suit, a question for the court. that unless more ingenuity and skill were required in making or applying the said improvement than are possessed by an ordinary mechanic acquainted with the business, there is an absence of that degree of skill and ingenuity which constitute the essential elements of every invention. Hotchkiss v. Greenwood, 11 How., 267. Mills for Ten years later, a case came before this court, in which the plaintiff claimed certain improvements in the construction of a machine for sawing lumber with the circular saw, including the manner of affixing and guiding the saw by allowing end play to its shaft, in combination with the means of guiding the device by friction rollers and other appliances. sawing logs with a circular saw had been well known long before the supposed invention; and, in construing the claim of the patent, this court said that the claim is for the precise organizaaffixing and guiding the circular saw by allowtion of the old machine, namely: the manner of ing end play to its shaft, in combination with the means of guiding it by friction rollers, so ing, that there is nothing new in the combinaas to leave the center entirely unchecked; addtion, and assigning as the reason for the conclusion, that the improvement had long been known and used in the circular saw for sawing timber of smaller dimensions than ordinary saw-logs. Enough appears to show that the machine in that case was larger than those of the kind which had preceded it; but the court remarked that that circumstance did not afford any ground in the sense of the patent law for a patent, for the reason that the ordinary mechanic was doing the same thing every day in making a working machine from the patent model. In order to reach invention, say the court in that case, the patentee must carry his improvement further; he must contrive *the [198 means of adapting the enlarged old organization to the new use, namely: the sawing of saw-logs; and claim, not the old parts, but the new de vices by which he has produced the new results. Phillips v. Page, 24 How., 167, 16 L. ed., 640. Applicants for a patent are required to file in the Patent Office a written description of their invention, and of the manner and process of making, constructing and using the same, in such full, clear, concise and exact terms as to enable any person skilled in the art or science to Decisions by this court of later date have make, construct and use the patented improve-been made to the same effect; as, for example, ment. Rights of the kind are given only to in- the court decided that the claim of the patventors or discoverers of some new and useful entee for making the cases of door locks and art, machine, manufacture or composition of matter, or some new and useful improvement thereof; and the law is well settled that nothing short of invention or discovery will support a patent for any such alleged new and useful improvement. Certain other important conditions are also annexed to the exercise of the right to obtain such a muniment of title for such an invention or discovery; as, for example, the improvement must not only be new and useful, but it must be one not known or used by others in this country, and not patented or described before the invention or discovery in any printed publication latches double faced, or so finished that either side of the case may be used for the outside, in order that the same lock or cased fastening may answer for a right or left hand door, was void, because the patentee did not show that he was the original and first inventor of the improvement, and intimated very strongly that the making of such a case, with two faces just alike, and so finished off in point of style that either side was fit to be presented outwards, was not a matter which could be patented, even if no locks with such cases had ever before been made. Jones v. Morehead, 1 Wall., 162, 17 L. ed., 663. Patented improvements which are not new Cas., 707; Tetley v. Easton, 2 C. B. (N. S.), and useful, or which did not require any inven- 706; Horton v. Mabon, 12 C. B. (N. S.), 437; tion or discovery to make the same, as compared Ormson v. Clarke, 14 C. B. (N. S.), 475; with what existed or was in use before, may be Parkes v. Stevens, L. R. 8 Eq., 358; S. C. L. declared invalid by the court in an equity suit. R. 5 Ch. App., 36; Envelope Co. v. Seymer, 5 Stimpson v. Woodman, 10 Wall., 121, 19 L. ed., C. B. (N. S.), 164; White v. Toms, 17 L. T. 868. (N. S.), 348; Ralston v. *Smith, 11 C. B. [200 (N. S.) 471: Ormson v. Clarke, 13 C. B. (N. S.). 337; Ralston v. Smith, 9 C. B. (N. S.). 117; Saunders v. Aston, 3 B. & Ad., 881; Seed v. Higgins, 8 El. & Bl., 755. Mere change in a machine, of one material for another, as wood or wood strengthened with iron for iron alone, is not invention in the sense of the Patent Act and, therefore, is not the subject of a patent. Hicks v. Kelsey, 18 Wall., 670. 21 L. ed., 852. Old processes are sometimes applied to new subjects, and where that was so, in a case which did not require the exercise of the inventive faculty, and without the development of any idea which could be deemed new or original in the sense of the patent law, it was held that the supposed improvement was not the subject of a patent, and that courts of justice may take judicial notice of a thing in the common knowledge and use of the people throughout the country. Brown v. Piper, 91 U. S., 38, 23 L. ed., 200. For these reasons, we are all of the opinion that the claim of the improvement described as the employment or use of two deflecting plates, one placed on each side of the circular saw, for the purposes set forth in the specification, is void, because it does not constitute a patentable invention. Suppose that is so; still it is insisted by the complainants that the decree of the circuit court should be affirmed in respect to the second and fourth claims of the patent. Clamps are employed or used by the complainants, arranged as shown, so as to have a lateral elastic movement, independent of the roller beds to which the clamps are attached, for the purposes set forth in the second claim. Admit that the claim is a valid one; still it is insisted by the respondents that they do not infringe that part of the patented invention and, consequently, that the decree of the circuit court should be reversed. Four adjustable feed-rollers are shown in the machine of the respondents, and in front of them there is a pair of clamps, of peculiar construction, the object and only practical effect of which, it seems, is to hold the upper edge of the stuff to be sawed in proper position while it is Evidently they difin contact with the saw. fer in form, method of attachment, purpose, and use from those described in the specificaInstead of that, the tion of the complainants. clamps described in the complainants' patent are attached to the inner ends of the rollerbeds, so that there are two journals at the back part of each clamp, which fit in boxes, and work or slide in recesses in the top and bottom pieces of the roller-beds. the clamps in the complainants' machine is govTo that it may be added, that the action of Proof of the state of the art is admissible in equity cases, without any averment in the answer touching the subject and, in actions at law. without giving the notice required when evidence is offered to invalidate the patent. It 199] consists of *proof of what was old and in general use at the time of the alleged invention; and may be admitted to show what was then old, or to distinguish what is new, or to aid the court in the construction of the patent. Meritorious inventors are entitled to protection; but it is settled law that a mere carrying forward of an original patented conception, involving only change of form, proportions or degree. or the substitution of equivalents, doing the same thing as the original invention by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results. Smith v. Nichols, 21 Wall., 115, 22 L. ed., 566. Effective support to the proposition, that nothing but invention or discovery will entitle an applicant to a patent, is also found in the reported decisions of the circuit courts, as appears from the following citations. Judge Story held, many years ago, that the mere applica-erned by the set screws which bear against rubtion of an old process, machine or device to a new use was not patentable; that there must be some new process or some new machinery to produce the result, in order that the supposed inventor may properly have a patent for the alleged improvement. Howe v. Abbott, 2 Story, 194; Bean v. Smallwood, 2 Story, 411; Glue Co. v. Upton, 6 Off. Gaz., 842; 7 Off. Gaz., 648. Conclusive support to the proposition that an applicant for a patent is not entitled to the publie protection, unless the supposed improvement involves actual invention or discovery, is fend in the oft repeated decisions of all the English courts having jurisdiction in such casand it is safe to remark, that the courts of that country apply the rule more readily, and with a much closer scrutiny, than do the arts of this country exercising the like jurisdiction. Ralston v. Smith, 11 H. L. Cas., 223; Harwood v. R. Co., 11 H. L. Cas., 654; Jordan v. Moore, L. R. 1 C. P., 624; Kay v. Marshall. 8 Cl. & F., 245; Bush v. Fox, 5 H. L. ber springs back of the boxes, the distance of the lateral vibration of the clamps being regulated by the stops, which are arranged to pass through the top pieces, the object of the arrangement being to give the clamps the ability to have a lateral elasticity and vibratory movement independent of the roller-beds, for the purpose, as stated in the claim, of compensating for the varying thickness of the different pieces of stuff, *and to keep the stuff to be sawed [201 in a proper relative position to the saw. Competent experts testify that the clamps in the machine used by the respondents have no lateral elastic or vibratory motion independent of the roller-beds, and that they cannot perform the functions of the clamps described and claimed in the patent set forth in the bill of complaint; and the court is of the opinion, from an examination of the models exhibited, that the testimony of the expert is correct. Keeping in view what has already been remarked, a few additional observations will be sufficient to dispose of the questions arising under the fourth claim of the specification, in which the complainants claim the employment of an adjustable bed, with clamps as described, in combination with the saw, when the saw has a stiffening plate in line with the adjustable bed, by which the stiffened or rounded side of the saw is made the line side. Taken as it reads, the fourth claim does not include a deflecting plate, and only a stiffening plate on one side of the saw; and, if not, it is difficult to see how the devices claimed in the combination will permit the stiffened or rounded side of the saw to be made the line side, unless the deflecting plate is added to the claimed combination. Add the deflecting plate to the combination, and it is quite clear that the claim may include parts sufficient to be operative; but when such stiffened side is thus made the line side, and the clamps embrace the saw as described, it is quite essential that the clamp on the line side should have a lateral elasticity with respect to the bed, and also the described swinging motion. Neither the clamp on the line side or the one on the opposite side in the respondents' machine have any lateral elasticity with respect to the roller-bed, or a swinging motion, and the one on the line side of the saw has no lateral motion whatever when the machine is in operation. Differences of opinion may possibly exist upon that topic, but all must agree that the claimed combination includes the clamps, and that infringement is not proved, unless it appears that the respondents use the entire combination. Having already decided that the re202] spondents do not use the clamps of the complainants, it is unnecessary to pursue the inquiry, except to say that it is settled law, that, where the respondent in constructing his machine omits one of the ingredients of the complainant's combination, he does not infringe the complainant's patent. Gould v. Rees, 15 Wall., 194, 21 L. ed., 41; Prouty v. Ruggles, 16 Pet., 341; Vance v. Campbell, 1 Black, 427, 17 L. ed., 168; Gill v. Wells, 22 Wall., 28, 22 L. ed., 711. (See S. C., Reporter's ed., 6-11.) Sheriff's deed-informality—prescription. 1. In Louisiana, if a sheriff has authority to sell land on execution and does sell it, and execute a deed to a purchaser in good faith, the latter may, although informalities occurred in the sheriff's proceedings, set up, when sued to recover the land, the prescription of five years under the statute of that State. 2. If the sheriff did not actually seize the prop: erty, it was such an informality as could be cured by possession for five years. Mr. Justice Bradley delivered the opinion of the court: This is a petitory action brought to recover certain plantation in Louisiana. The plaint (now defendant in error) claimed the land un der an act of donation from her uncle, Ackley Perkins, passed the 5th of September, 1861 Perkins had purchased the lands at sheriff's sale made August 3d, 1861, under a vendor's lien, and gave a twelvemonth's bond for the purchase money. One Williams, and Wm. S Pike, the defendant below (now plaintiff in erThe bond ror), were his sureties on this bond. not being paid, a writ of fieri facias, under the laws of Louisiana, was issued upon it against the goods and lands both of Perkins and bis sureties. The sheriff, under and by virtue of this writ, sold the plantation in question on the 6th of January, 1866; and Pike, to save his own property and to protect himself against his liability as surety, became the purchaser, paid the incumbrance, and went into possession on the day of sale. He had been in possession over five years, *when this action was [7 brought; and, amongst other things, pleaded prescription of one, three and five years. On the trial of the cause, the plaintiff having proved the act of donation from her uncle, Ackley Perkins, on which she relied, and the previous purchase of the property by him at sheriff's sale in August, 1861, the defendant gave in evidence the twelvemonth's bond executed by Perkins and his sureties for the purchase money at said sale, the fieri facias issued thereon in October, 1865, and the sheriff's deed to him dated Jan. 6, 1866; and introduced evidence tending to show that he, the defendant, had been in possession of the property in question for a period of five years, and that he purchased the property at the sheriff's sale; and thereupon, he asked the court to charge, that if the jury found that he had been in possession for a period of five years, and that he purchased the same from any person authorized to sell at public auction, then any informality connected with or growing out of the sale was cured by the lapse of five years. The court gave the instruction asked, but added: "If the sheriff did not seize the property, that is an informality which is not cured by possession for five years." The counsel for the defendant excepted to this modification. Other bills of exception were taken in the course of the trial, but as the one quoted was, in our view, well taken, and is decisive of the cause, it is unnecessary to advert to them further. 1834. section 4, it was enacted, By a law of Louisiana, passed March 10, "That all informalities connected with or growing out of any sale made by a parish judge, sheriff, auctioneer, or other public officer, shall, after the lapse of five years from the time of making the same, be prescribed against by those claiming under such sales, whether against minors, married women, or persons interdicted." This law continued in force until 1870, when it was superseded by a general provision contained in the Revised Statutes of 1870, sec. 3392, p. 659, and in the Civil Code, as published in that year, article 3543, the terms of which are as follows: "All informalities connected with or growing out of any public sale made by any person authorized to sell at public auction shall be prescribed against by those claiming under such sale, after the lapse of five years from the time of making it, whether against minors, married women, or interdicted persons." Other articles of the Civil Code of Louisiana on the subject of prescription require that the person who sets it up in relation to an immovable must have acquired the immovable in good faith and by a just title. Thus, article 3478 declares that "He who acquires an immovable in good faith and by a just title, prescribes for it in ten years." Articles 3484 and 3485 declare that by the term "just title," in cases of prescription, is not meant that which has been derived from the true owner, but that which has been received from any person whom the possessor honestly believed to be the real owner, 9] provided it were such as to transfer the ownership of the property; that is, such as by its nature would have been sufficient to transfer the ownership, if it had been derived from the real owner, such as a sale, exchange, legacy, or donation. The Supreme Court of Louisiana has frequently had occasion to construe the effect of these laws. In Walden v. Canfield, 2 Rob. (La.), 468, where prescription was set up under a title based on a marshal's sale, the court said: "The defendants have produced a regular judgment, writ of execution, and a deed of sale from the marshal to their author; and, under the well settled and repeatedly established doctrine of our jurisprudence, that in relation to sales under execution, where a purchaser shows a judgment, writ of execution and sale, under which he holds, his title will be considered as legal and valid, we think that on this point the defendants have satisfactorily complied with the requisites of the law; and that, as their title being a just one; that is to say, one which of itself was sufficient to transfer the property in dispute, it is such as can legally serve as the basis of the prescription. It is true that the plaintiff has attempted to attack the defendants' original sale on the ground of informality in the other proceedings of the marshal; but this, in our opinion, cannot change, or in any way alter the effect of the defendants' title, if they have really possessed under it, during the time required by law to acquire the property by prescription, before the institution of this suit, or, in other words, before the alleged informalities were set up against the presumed legality and validity of their title." In Leduf v. Bailly, 3 La. Ann., 8, the same doctrine was held where the irregularity complained of was that the sheriff's deed did not purport to convey the interest of the party from The judg whom the plaintiffs deduced title. ment and execution were against him and others, but the sheriff's deed omitted his name. The defendants holding under this deed pleaded prescription, and the court held it a sufficient title to base prescription upon. "No evidence has been adduced," said the court, "to repel the legal presumption that the defendants' possession commenced in good faith." So, in Brien v. Sargent, 13 La. Ann., 198, want of due notice of *seizure by the sher- [10 iff was held to be no obstacle to prescription being set up by one who claimed under the sheriff's sale; there being no evidence to impeach the defendant's good faith, and he having shown a regular judgment, execution and sheriff's deed. The subsequent case of Robert v. Brown, 14 La. Ann., 605, shows what kind of objections to a judicial sale may render it ineffectual as a basis of prescription. There a commission to sell the property of minors was issued without any order of sale. The court held that there was a total want of authority to sell; and that, in such a case, the prescription of five years could not be claimed under the statute, but that it only cured those informalities which may occur in the execution of a decree or other authority to sell. This case is analogous to that which would be presented if a sale were made under an execution without any judgment to support it. From these authorities (and others to the same effect could be cited) it is evident that although informalities occurring in a sheriff's proceedings under execution may be good ground for annulling a sale made by him if taken advantage of in time, yet that if the sheriff has authority to sell and does sell, and execute a deed to the purchaser, the latter, if a purchaser in good faith, may set up the prescription of five years under the statute. Applying this rule to the case before us, we think the court erred in holding that, if the sheriff did not actually seize the property, it was such an informality as could not be cured by possession for five years. The case of Morton v. Reynolds, 4 Rob. (La.), 26, referred to by the defendant in error, which seems to hold that the only informalities cured by five years' possession are those occurring in the advertisement of sale, is overruled by subsequent cases, and is contrary to the general current of decisions made by the Supreme Court of Louisiana. The case of Watson v. Bondurant, 21 Wall., 123, 22 L. ed., 509, was very different from the present. In that case the question of prescription did not arise. Bondurant, the mortgagee, procured the property to be sold by the sheriff without any actual seizure or notice to Watson who was in possession, and bought the same himself, and then brought his action to recover possession. Under those circumstances, it was competent to Watson *to take ad- [11 vantage of any informality in the sale; and we held that the want of seizure invalidated it. So, in this case, if the defendant in error had proceeded in due time, the informalities relied on, if existing in point of fact, would probably have been sufficient to invalidate the sale. But that is not the question here. The question here is not whether the plaintiff in error had a good title, but whether he had such a just title as the law of Louisiana requires, to lay the foundation of prescription; and of this we think, under the |