| U.S. Circuit Court for the District of Southern Ohio | May 15, 1859
(charging jury): The novelty or originality of this invention is not controverted, but it is insisted by the defendants that-there is such an entire absence of utility in the improvement as to affect the validity of the patent itself. The statute undoubtedly makes utility essential to the validity of a patent, and whether it exists in a particular case, is to be decided by the jury upon the evidence, subject to the decision of the court upon the law. ■ It is very familiar law that the'patent itself affords prima facie evidence of utility. The patentee is obliged to accompany his application with his oath to the usefulness of his invention, and every patent granted is based upon the hypothesis that there is some utility. Still it is. competent for the defendant to rebut this presumption by evidence, and if he make it appear that the invention is utterly worthless, it is a good defense. In regard to this matter,, however, it is very well settled that the courts will not be very rigid as to the degree of utility. It will not inquire into the precise quantum of value; but, if the invention be useful in any degree, and not absolutely worthless, the patent will be sustained. In this case, there has been a great deal of conflicting testimony. The plaintiff proves-, by several men that have used it, that the stove works well; while others testify that it is a good stove and in demand. On the other hand, some who have used it. pronounce it of no value; while others again, who have been examined on this point, express an opinion, derived from actual knowledge of its operation, or from theoretical observation, that, in their judgment, this improvement adds nothing to the value of the old “Premium Stove.” It is left with the jury to apply this testimony in accordance with the law; it is for you to judge of the-credibility of the witnesses, and the weight of their testimony, upon this point; but I may also remark that if you find that the defendants have used this improvement, or
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Upon the question of infringement, if the front plate is claimed in the specification as a material part of the plaintiff’s combination, and if it be material and necessary to the action of the plaintiff’s stove, and the defendants have not used it, or something which is an equivalent for it, there is no infringement. Whether it is claimed as material in the specification, is a question for the ■court. The patent is for an improvement ■on a stove before known, called the “Premium Stove.” It would seem to be the object of the invention to produce an equal distribution of heat, without the aid of a damper, and in any stage of the fire. After describing various changes and appliances to effect these objects, and among them the “diving-pipe,” the patentee proceeds to say: “This (the diving-pipe) is not alone sufficient, because of the tendency of the current to take the shortest and most direct path to the place of exit; and without the plate ‘a’ at the front of the cold air-chamber, with a low fire, most of the heat would pass beneath the oven; while with a fire-box full of fuel, most of the heat would pass over the oven,” etc. “To prevent such irregularities, therefore, I place the plate ‘a’ so that it will form a flue in front of the cold air-chamber,” etc. It would seem, from these extracts, and from the whole specification, that the plaintiff has fully described the front plate, and that he regarded it as an important agent for the production of the effect; at which he aimed. It is true that in the “summing-up,” the front plate is not specifically designated. He there claims, as his invention, “the combination of the diving-pipe i, with the flues F, arranged as herein described, for the purpose of evenly distributing and equalizing the heat on the four sides of the oven, without using or requiring dampers, as herein set forth.” But in giving a construction to a patent, it is the duty of the court to look to the whole specification, to the body of the patent. And, in the “summing-up” itself, the patentee refers to the arrangement “as herein described,” and “as herein set forth,” embracing most clearly, .as I think, by these phrases, the front plate. I am obliged to say, therefore, that, in my opinion, he claims it as a material element of his combination.