U.S. Supreme Court
Wood v. Underhill, 46 U.S. 5 How. 1 1 (1847)
Wood v. Underhill
46 U.S. (5 How.) 1
In order to obtain a patent, the specification must be in such full, clear, and exact terms as to enable anyone skilled in the art to which it appertains to compound and use the invention without making any experiments of his own.
If the patent be for a new composition of matter, and no relative proportions of the ingredients are given, or they are stated so ambiguously and vaguely that no one could use the invention without first ascertaining, by experiment, the exact proportion required to produce the result, it would be the duty of the court to declare the patent void.
But the sufficiency of the description in patents for machines, or for a new composition of matter, where any of the ingredients do not always possess exactly the same properties in the same degree, is generally a question of fact to be determined by the jury.
Where a patent was obtained for a new improvement in the mode of making brick, tile, and other clay ware, and the process described in the specification was to mix pulverized anthracite coal with the clay before moulding it, in the proportion of three-fourths of a bushel of coal dust to one thousand brick, some clay requiring one-eighth more, and some not exceeding half a bushel, this degree of vagueness and uncertainty was not sufficient to justify the court below in declaring the patent void.
The court should have left it to the jury to say, from the evidence of persons skilled in the art, whether the description was clear and exact enough to enable such persons to compound and use the invention.
It appeared that in the year 1836, Wood took out amended letters patent for "a new and useful improvement in the mode of making brick, tile, and other clay ware," and filed the following specification of his invention:
"Be it known that I, the said James Wood, have invented a new and useful improvement in the art of manufacturing bricks and tiles. The process is as follows:"
"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 brick will be correct. Some clay may require one-eighth more, and some not exceeding a half-bushel. The benefits resulting from this composition are the saving of fuel, and the more general diffusion of heat through the kiln, by which the whole contents are more equally burned. If the heat is raised too high, the brick will swell and be injured in their form. If the heat is too moderate, the coal dust will be consumed before the desired effect is produced. Extremes are therefore to be avoided. I claim as my invention the using of fine anthracite coal or coal dust with clay for the purpose of making brick and tile as aforesaid, and for that only claim letters patent from the United States."
"Dated 9 November, 1836"
In July, 1842, he brought a suit against the defendants in error, for a violation of this patent.
And at the trial the defendant objected to the sufficiency of the specification
"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, but that clay which requires most burning will require the greatest quantity of coal dust; the exact proportion cannot, therefore, be specified; but in general three-fourths of a bushel of coal dust to one thousand brick will be correct. Some clay may require one-eighth more, and some not exceeding half a bushel, so that there is no fixed rule by which the manufacturer can make the mixture, but that must be ascertained by experiments upon the clay, and the claiming clause in the specification is only for the abstract general principle of mixing anthracite coal dust with clay for the purpose of making brick, without any practical rule as to the proportions, which is too vague and uncertain to sustain a patent,"
which objection was sustained by the court. The plaintiff excepted. And the verdict and judgment being against him, the case was brought here upon this exception. chanrobles.com-red