Without Undue Experimentation vs. Without Any Experiments

Background of the Invention

Wood’s US Patent No. 97, originally issued in 1829 and later reissued in 1836, was directed to a process of mixing pulverized anthracite coal dust with clay before molding the bricks or tiles. In his patent specification, Wood stated:

Take of common anthracite coal, unburnt, such quantity as will best suit the kind of clay to be made into brick or tile, and mix the same, when well pulverized, with the clay before [it] is moulded; that clay which requires the most burning will require the greatest proportion of coal-dust; the exact proportion, therefore, cannot be specified; but, in general, three fourths of a bushel of coal-dust to one thousand bricks will be correct. Some clay may require one eighth more, and some not exceeding a half-bushel.

The basic idea here is to use pulverized coal as a sort of internal fuel that is mixed throughout the brick or tile material, allowing it to burn more efficiently and evenly during the firing process. Wood claimed that this composition provided benefits of “saving of fuel, and the more general diffusion of heat through the kiln, by which the whole contents are more equally burned.”

The Lower Court Decision

In 1842, Wood sued William Underhill and Aschel Gerow for infringement. This was a big case with Wood alleging that the defendant had made 100 million bricks and 100 million tiles using his patented process. Wood requested damages of $30,000, being triple his alleged actual damages of $10,000. This is over $1 million in 2024 dollars based on a 2% annual inflation rate.

At trial, the defendant argued that Wood’s specification was insufficient “because no certain proportion for the mixture is pointed out, but only that such quantity of coal must be taken as will best suit the kind of clay to be made into brick or tile.” They contended that there was “no fixed rule by which the manufacturer can make the mixture, but that must be ascertained by experiments upon the clay” and that the claiming clause was “too vague and uncertain to sustain a patent.” The circuit court agreed with the defendant and instructed the jury that the specification was too vague and uncertain to support the patent. The jury found for the defendant, and Wood appealed to the Supreme Court. At the lower court, the defendant also argued that Wood’s claimed invention was not new, having been known and used by numerous individuals in England, Wales, Canada and the United States prior to Wood’s alleged invention, but that issue was left moot by the decision that the specification was insufficient.

The Supreme Court’s Decision

In its decision, the Supreme Court reversed in a unanimous opinion authored by Chief Justice Taney. The key issue, as framed by the Court, was “whether his description of the relative proportions of coal-dust and clay, as given in his specification, is upon the face of it too vague and uncertain to support a patent.”

The Court acknowledged that if a specification “gives only the names of the substances which are to be mixed together, without stating any relative proportion” or if the proportions “were stated ambiguously and vaguely” then it would be proper for a court to declare the patent void. This would be the case when “it would be evident, on the face of the specification, that no one could use the invention without first ascertaining by experiment the exact proportion of the different ingredients required to produce the result intended to be obtained.”

However, the Court found that this “degree of vagueness and uncertainty” did not exist in Wood’s specification. The Court noted that Wood provided “a certain proportion as a general rule; that is, three fourths of a bushel of coal-dust to one thousand bricks.” While Wood mentioned that some clay may require slightly more or less coal dust, the Court regarded these as “exceptions to the rule he has stated; and as applicable to those cases only where the clay has some peculiarity, and differs in quality from that ordinarily employed in making bricks.”

The Court explained that “the general rule is given with entire exactness in its terms” and the variations mentioned seemed intended “to guard the brick-maker against mistakes, into which he might fall if his clay was more or less hard to burn than the kind ordinarily employed in the manufacture.” The Court acknowledged the possibility that clay qualities may differ so widely that the specification would be of no value and the invention could not be used without experimentation, but stated that this was not apparent from the face of the specification and was a question of fact for the jury to decide based on expert evidence. But the bottom line is that:

The Circuit Court therefore erred in instructing the jury that the specification was too vague and uncertain to support the patent, and its judgment must be reversed.

The case was remanded for a new trial. As suggested here, Wood v. Underhill highlights important distinctions between legal and factual issues in patent cases and the respective roles of the judge and jury.