Then and Now: 1800’s Supreme Court Patent Cases

by Dennis Crouch

In this new series, I’m looking back to 19th Century Supreme Court patent cases; looking for their wisdom; and considering their ongoing importance.

Winans v. Denmead, 56 U.S. 330 (1853) is cited as an early doctrine of equivalents (DOE) case, although I see it also as an early claim construction decision. According to Westlaw, is the 10th most cited patent case of the 19th Century.  At the time of the case, Winans was on his way to becoming one of the wealthiest Americans by making and selling railroad equipment.

As shown in the diagram below, the Winans patent covers a railroad car for transporting coal, etc. The car has a cone-shape particularly “the form of a frustum of a cone, substantially as herein described”  The shape allowed the car to carry “more coal in proportion to its own weight than any car previously in use.”  Further, excess load did not distort the shape because it “presses equally in all directions.” Id.

The accused infringer inspected a Winans-made car and then made its own — although using an octagonal shape rather than circular as in the patent (looking down as in fig 1).  The defendants argued this difference in should have resulted in a non-infringement verdict;  Winans argued that this difference was immaterial because the octagonal car was almost the same shape and obtained the same useful results.  Further, after being used for a while, the sheet metal used will shape itself into a circle.

The jury was asked Winans asked for jury instructions akin to the function-way-result test:

whether ‘the form adopted by the defendants accomplished the same result, substantially, with that in view of the plaintiff, and upon substantially the same principle and in the same mode of operation.’

However the lower court took a much narrow stance and effectively instructed the jury that they could only find infringement against conical bodies since the operation of the invention is “due alone to conical vehicles and not to rectilinear bodies.”  With that narrow instruction, the jury could not find infringement.

The Supreme Court reversed course — concluding that the court must not allow form to dictate substance.

[I]t is the duty of courts and juries to look through the form for the substance of the invention—for that which entitled the inventor to his patent, and which the patent was designed to secure; where that is found, there is an infringement; and it is not a defence, that it is embodied in a form not described, and in terms claimed by the patentee. . . .

The exclusive right to the thing patented is not secured, if the public are at liberty to make substantial copies of it, varying its form or proportions.

In the end, however, I see this case largely about claim construction. The Supreme Court explained that a cone in Euclidean sense is impossible to construct except by imagination.

It may safely be assumed, that neither the patentee nor any other constructer has made, or will make, a car exactly circular. In practice, deviations from a true circle will always occur.

Thus, it is clear to the court that the “cone” limitation in the claim does not require an exact cone.  The court went on to interpret the meaning of the patent as covering a design

“so near to a true circle as substantially to embody the patentee’s mode of operation, and thereby attain the same kind of result as was reached by his invention. . . . It must be the same in kind, and effected by the employment of his mode of operation in substance.”

The court ordered that on remand the jury can consider infringement under this broader view of the patent.

Justice Curtis wrote the 5-4 majority opinion.

The dissent by Justice Campbell began with a suggestion that the substance of the invention is likely obvious (lack of invention).

The merit of the plaintiff seems to consist in the perfection of his design, and his clear statement of the scientific principle it contains. . . . There arises in my mind a strong if not insuperable objection to the admission of the claim, in the patent for ‘the conical form,’ or the form of the frustum of a cone,’ as an invention.

The dissent went on – assuming that the patent is valid — noted that it should be assumed that a patentee will draft claims in a way that reach “exactly the limits of his invention” and that it is improper for the court to “extend, by construction, the scope and operation of his patent, to embrace every form which in practice will yield a result substantially equal or approximate to his own.”

The plaintiff confines his claim to the use of the conical form, and excludes from his specification any allusion to any other. He must have done so advisedly. He might have been unwilling to expose the validity of his patent, by the assertion of a right to any other. Can he abandon the ground of his patent, and ask now, for the exclusive use of all cars which, by experiment, shall be found to yield the advantages which he anticipated for conical cars only?

The dissent went on to complain that the majority’s approach has little bound —

The claim of today is, that an octagonal car is an infringement of this patent. Will this be the limit to that claim? Who can tell the bounds within which the mechanical industry of the country may freely exert itself? What restraints does this patent impose in this branch of mechanic art?

The patentee is obliged, by law, to describe his invention, in such full, clear, and exact terms, that from the description, the invention may be constructed and used. Its principle and modes of operation must be explained; and the invention shall particularly ‘specify and point’ out what he claims as his invention. … Nothing, in the administration of this law, will be more mischievous, more productive of oppressive and costly litigation, of exorbitant and unjust pretensions and vexations demands, more injurious to labor, than a relaxation of these wise and salutary requisitions of the act of Congress. In my judgment, the principles of legal interpretation, as well as the public interest, require, that this language of this statute shall have its full significance and import.


In Graver Tank, the Supreme Court identified Winans as the origin of the doctrine of equivalents.

The essence of the doctrine is that one may not practice a fraud on a patent. Originating almost a century ago in the case of Winans v. Denmead, 15 How. 330, 14 L.Ed. 717, it has been consistently applied by this Court and the lower federal courts, and continues today ready and available for utilization when the proper circumstances for its application arise.

Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U.S. 605, 608 (1950).

Still, when I read the case, I see claim construction. Notably, the question presented by the court is whether the word ‘cone’ is properly construed and the court answered that it is nearly a circle, and the purpose of the invention helps to understand the limit of that subjective limitation.

In our judgment, the only answer that can be given to these questions is, that it must be so near to a true circle as substantially to embody the patentee’s mode of operation, and thereby attain the same kind of result as was reached by his invention.

Id. The reason the court felt obliged to consider this construction is its conclusion that “construing the letters-patent” “is a question of law, to be determined by the court.”  The dissent seemed to similarly agree that the focus is about claim construction — arguing that the majority’s “construction” is too broad.

= = =

Graver Tank claims Winans as the origin of the doctrine of equivalents — and it is the first time that the US Supreme Court used the term “equivalents” in this fashion.  However, Winans itself cites to a number of prior English cases that focus on the idea of construing patent claims to give effect to the substance of the invention rather than the particular form. Walton v. Potter and Horsfall; Russell v. Cowley & Dixon; Morgan v. Seaward.

36 thoughts on “Then and Now: 1800’s Supreme Court Patent Cases

  1. 8

    In view of the commentary debate here over the 1836 Patent Act re “claims,” here is key text electronically copied from original printed text [note minor OCR errors] from that statute. See especially the last sentence here:
    “But before any inventor shall receive a patent for any such new invention or Specification. discovery, he shall deliver a written description of his invention or discovery, and of the manner and process of making, constructing, using, and compounding the same, in such full, clear, and exact terms, avoiding unnecessary prolixity, as to enable any person skilled in the art or science to which it appertains, or with which it is most nearly connected, to make, construct, compound, and use the same ; and in case of any machine, he shall full £ explain the principle -and the several modes in which he has contemplated the application of that principle or character by which it may be distinguished from other inventions ; and shall particularly specify and point out the part, improvement, or combination, which he claims as his own invention or discovery. “

  2. 6

    I think the DOE test and the test for obviousness should be the same test. If the prior art, alone or in combination, perform the same function, in the same way, to achieve the same result, then the claimed invention is obvious. If not, the claim is not obvious.

    1. 6.1

      Dear Pete —

      When I was a youn’un, I thought the same thing. As the wisdom of age settled upon me, I realized it just can’t be. They’re completely different inquiries, to evaluate qualitatively different properties:
      * obviousness has to be evaluated without resort to hindsight.
      * equivalents has to be evaluated with full benefit of hindsight.

  3. 5

    The last paragraph of Prof. Crouch post has been illuminating for me.
    I always found it hard to distinguish the substance of claim construction from the substance of the doctrine of equivalent, because in both, the question seems to be about what the person of ordinary skill would have understood to be covered by the claims. Viewing a case as a claim construction case or a DOE case based on whether the procedure looks like judges deciding the scope of the claims or reviewing an infringement verdict has clarified things for me.

  4. 4

    [W]hen I read the case, I see claim construction.

    Almost. Patents were not required to have claims at this point in history, so there was patent construction, but not yet claim construction. I am not a fan of the DoE, but the doctrine makes a great deal more sense in a world in which the court’s job is to discern “the invention” disclosed in a patent and to give effect against an infringement of that invention, than in a world in which the court’s job is to construe claims.

    1. 4.1

      Are you sure? I was sure claims became required in the patent act of 1836 (and were sometimes used before that date).

      1. 4.1.1

        Naturally, I could be wrong about this, and welcome correction from those more learned in this subject, but it was my understanding that the requirement for claims entered the U.S. system in the 1870 act. In any event, that is Prof. Lemley’s contention (I am just getting this from his scholarship), and I think that his evidence for this contention carries the day. On this point, Prof. Mossoff agrees (see, fn. 45).

        The 1836 Patent Act says (in relevant part, see §6) that the ” a written description of his invention… shall particularly specify and point out the part, improvement, or combination, which he claims as his own invention or discovery… .” In other words, there is nothing about claims defining the invention, but rather it is the written description that is meant to make clear that which the inventor claims as the invention.

        By contrast, the 1870 Act (§26) requires that the “application… shall particularly point out and distinctly claim the part, improvement, or combination which he claims as his invention or discovery… .” Here is the first requirement for actual claims, as we understand them today.

        You are quite right that even before the 1870 Act required claims, applicants frequently used them, but until 1870 they were merely useful options, rather than strict requirements. Because they were not required before 1870, they were not dispositive on the infringement inquiry before 1870. Rather, in 1853 when Winans was decided, the infringement inquiry focused on what the specification disclosed as the invention, with the claims merely being useful tools to help that inquiry, rather than dispositive limits on the inquiry.


          Greg, if that is correct – that “distinctly claim” [as distinct from “a written description of the invention” of the 1836 Act] were only actually required in the 1870 Act – that is a widespread misunderstanding. It would seem to make reliance on prior Sup. Ct. cases even less reliable.

      2. 4.1.2

        I am afraid that I put too many URL links in my response, and now it has been swallowed up. Hopefully it will make it through eventually.

    2. 4.2

      Thanks Greg. My understanding is that claims have been required since the Patent Act of 1836 — this is an 1847 patent.

      The claims at issue here use the “as described” language to directly tie-in the specification into the claims, although the court suggested here that such a statement was not necessary. Rather, a tie-in to the specification will be assumed unless the inventor “manifests an intention to disclaim some of those forms.”

      1. 4.2.1

        Everyone is right.

        The Act of 1836 required claims.

        The Act of 1870 tightened up the requirement. I don’t know whether the specific language “particularly pointing out and distinctly claiming the subject matter” was new in 1870 or not, but the application of the law tightened up. “Substantially as shown and described” went out the window with the Act of 1870.


          Thanks, that is helpful. Just to make sure that the forest is not being lost for the trees here, I want to re-iterate that peripheral claiming as a means of defining the scope of the patent right came in with the 1870 act. Under the 1836 act—notwithstanding the “proto”-claims required under §5—the U.S. was still operating under a central claiming regime. My substantive point was that the DoE makes more sense in that central claiming weltanschauung than it does under the current peripheral claiming regime currently in force.

          In other words, Graver Tank was a mistake. The Court carried over a doctrine from Winans, without noticing that this logic for this doctrine does not really obtain without the rest of the legal background that had been jettisoned in the time since Winans.


            I too like the central versus peripheral discussion.

            But at the end of the day, all that we have to work with are words, and be those words at the center or at the periphery, the DOE serves such that wooden adherence to an exacting sense of “the word” does NOT rob the innovator of the meaning behind the words.

            In both central claiming and in peripheral claiming, the words of the claims — being words — carry a penumbra.

            Graver Tank was not a mistake. The penumbra of words does not disappear because we moved from central claiming to peripheral claiming.

            Slavish attention (and demand) for excessive “picture claims” is NOT a good thing — leastwise for most all forms of innovation that by its nature is on the edge of what “well-established” words may carry.

            To make a literary comparison, Shakespeare today is regarded as one of the best writers of all time. But in his day, he was regarded as one that ‘mangled’ words and extended their “penumbra” to new and different meanings.

            We should be wary of those that slavishly seek to constrain the penumbra of claims, who seek to protect only that which may be presented in excessive ‘picture claim’ format.


              … even in peripheral claiming, the words are informed by how they are used in the specification.

              Note as well that MANY complaints about p00r examination come about because of “key word searching” of words in claims where it is apparent that rejections are formulated without regard to what the claim words mean in regard to the provided specification. I posit that such is an offshoot of a wooden approach to “peripheral claiming.”

  5. 3

    Where do the words “The essence of the doctrine is that one may not practice a fraud on a patent” in Graver Tank come from? It is not cited as an actual quote from Winans v. Denmead, which is cited in the seperate next sentence as the source of the DOE.

    1. 3.1

      And in your commendable looking back at old Sup. Ct. patent cases, including those cited for DOE, I would like to see how the accused product vis a vis the actual claims in Graver Tank can possibly be reconciled with the consistent Fed. Cir. requirements or limitations of DOE?

  6. 2

    Thanks Dennis — good observation.

    A similar case — O’Reilly v Morse. Today’s Supremes cite it as a “subject matter” case. No no no. It’s an enablement case. Remember that the telegraph was invented only about ten years after Faraday first recognized the existence of electric current, and Oersted recognized electromagnetism. (In fact, it sounds like Morse coined the term for his patent application).

    At the time that the telegraph was invented, “making or printing intelligible characters, signs or letters at any distances, being a new application of [the power of electric or galvanic current]” was an “unpredictable art,” and the reasoning of O’Reilly tracks the cases about “broad claims with narrow enablement” today, not today’s subject matter cases.

    1. 2.1

      I definitely agree that Morse fits more naturally into the §112(a) context of the contemporary patent act than into the §101 context. I am surprised, however, that you read it as an enablement case rather than a written description case. Why so?

      1. 2.1.1

        The 112 trinity of enablement, possession and description most likely should not be attempted to be completely segregated into three distinct items.

        If you have described something (properly) then you have enabled it, is this not so?

        If you have described something (properly) then you have possessed it, is this not so?

        How would one possess some thing that was not described? (Given an understanding that descriptions carry inherency).

        How would one enable something not described? (Again, given that descriptions carry inherency).

        How does one describe something not possessed?

        How does one describe something not enabled? Perhaps this last question is the “bug a boo” colliding with the other issues of claiming results (and the English language difficulty that “result” is itself a relative term.


          The gulf between written description and enablement is an interesting thought experiment, but a couple of simple examples show that you can of course “describe” something in words yet fail to “enable” it.

          A common yet humorous example is including a statement in the specification that the invention can be carried out by use of a time machine. Or a patent on an automobile internal combustion engine that the specification says can achieve 200 miles per gallon, but it only actually describes conventional engines from the 1960s. You’ve “described” the invention–you included words in your specification that mirror what you’re claiming–but no one could actually create it based on that description. In a patent system where (aside from some narrow areas) you don’t have to actually implement anything to get a patent on it, the separateness of enablement and written description requirements is necessary.

          You can see this in prior art as well, which also follows 112 principles requiring that prior art be enabled if used for anticipation. I saw one well-respected judge reject a modern patent on biometrics because he claimed to have seen the same invention in the original 1960s “Star Trek” series, because he neglected the enablement requirement. If you didn’t have an enablement requirement for prior art, pretty much everything being patented today would be invalid based on sci-fi films and books published several decades ago. And in prosecution, people would pursue patents on far flung concepts that they don’t enable, in the hope of getting a patent lying in wait until someone else in the future succeeds and actually makes it.

          Seems like you acknowledge this by using the phrase that some has to “describe something (properly),” but what does “properly” mean other than the fact that the description must be sufficient to allow a skilled artisan to be able to practice what’s described?


            LR, you answer your own question to me by circling back with that last paragraph. A partial description is just that: partial.

            It does not get you were you need to be under the law. It is NOT an adequate description. Thus, you have not met the caveats I presented and you have not made a description. Yes; the qualifier of “proper” is critical and it is that qualifier that can be seen to make attempts to segregate the notions into a f001s game.

            Another question: has anyone truly possessed something that they have not described?

            How do you know what they possessed unless you were reading their description?

            Of course, an important aspect here is that one may possess something inherently and may not be totally aware of the scope of what they possess. But this is an exceptionally common occurrence, and I run into inventors all the time that they think that they have only invented “s,t, and u,” while what they have actually invented (inherently) is “S,s, T, t, U, u, and V, v, and W.”

            They certainly both possess and described the larger set — even as they were unaware of what they had in their hands. Part of the value of my craft is to prove, develop and flesh out what the innovators already have even as they may be unaware of what they have.


            I like the analogy to unreachable inventions, time machines, etc., however, this often gets confused with, obvious variants of what you made that are imminently reachable but not practical because of financial resources. This is Sanofi v. Amgen – obvious variants of antibodies are routine and easily made, but the Sanofi decision suggests you cant claim variants because you didn’t have a budget large enough to make all imminently possible alternatives. Written description should have a balance regarding unreachable vs. imminently reachable variants.


              This is Sanofi v. Amgen – obvious variants of antibodies are routine and easily made, but the Sanofi decision suggests you cant claim variants because you didn’t have a budget large enough to make all imminently possible alternatives.

              Well, yes, Amgen’s claims read on antibodies that were obvious in view of the disclosure of Amgen’s antigen. The problem is that their claims also read on nonobvious antibodies—the claims read on all antibodies that bind to the antigens, both those that Amgen had invented and those that it had not invented. That is the problem. One cannot legitimately claim that which one has not demonstrably invented.


              Let’s explore:

              Written description should have a balance regarding unreachable vs. imminently reachable variants.

              If you have an unreachable item, have you satisfied the written description requirement for something that cannot be reached?

              How can one describe that which cannot be reached (and here, ‘described’ in the patent sense — not ‘my’ sense)…?

              (Note that I am purposefully not using the ‘offensive’ word of “properly”).


          anon @ 2.1.1

          Here are my two favorite examples that show the difference between written description and enablement.

          Patent 1: the entire specification is “The contents of the Library of Congress and all university libraries is hereby incorporated by reference.” That one sentence is the whole spec. That enables essentially everything that will be invented over the next decade, but gives written description support for nothing.

          Patent 2 has a 100-page specification with great detail for building a perpetual motion machine. This has written description support for lots and lots, and enablement support for essentially nothing (perhaps some of the sub-assemblies are enabled).


          Gentlemen, I appreciate the feedback, but you are not following the caveats:

          If you have described something (properly) then you have enabled it, is this not so?

          If you have described something (properly) then you have possessed it, is this not so?

          Description is not the same as science fiction writing (writing about a time travel device is simply not the same thing as describing a time travel device).

          I cannot truly describe an Un-enabled item because the item that prevents the enabling has not been described.

          Partial descriptions are not descriptions.


            Don’t use “properly.” It’s pretty clearly invoking the “no true Scotsman” fallacy. link to

            I know what “described adequately for ‘written description’ support” means. I know what “described adequately for ‘enablement’ support” means. Those two are each well defined, and they are different, see examples at and

            “Properly” seems to mean exactly what anon wants it to mean, and therefore it’s meaningless.

            “When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.” “The question is,” said Alice, “whether you can make words mean so many different things.” “The question is,” said Humpty Dumpty, “which is to be master—that’s all.”


              The point being LESS what “I” want it to mean and MORE what it means under the law (and yes, that includes both describing for the effect of ‘written description’ and for the effect of ‘enablement support.’

              There is only one description provided in a patent application.


              That some have divined multiple purposes and want differences of that single supplied description IS a part of the underlying problem here.

              That is rather the point at hand.

              I am not the one trying to take a single word and make it mean different things.


                Dear anon —
                Youre drifting off point. Your premise @ 2.1.1 and is taht the various requirements of 112 arent separable.

                Your response here at is a non sequitur. Of course there’s only one description. but that doesnt adress the issue — There’s one description, but it has to meet several separate requiremnts. the requirments are distinct from eah otherM

                There are los of areas of the law where a single thing has to meet multiple legal rwquirmets simultaneously.

                If you reply irrationally, i’l put you back on my “ignore” list. Think before you start typing.


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