Judson v. Moore. plow made under the Bales patent substantially the same thing as that manufactured under the Marquiss patent? If so, it is an infringement. A mere addition to a patented invention will not justify the use of the invention first patented. Upon the question of infringement we are frequently obliged to depend in great measure upon the testimony of experts. Two of these have been examined in this case—Mr. Knight and Mr. Clifton. Both have stated that there is no substantial difference between the two moles, and they are not contradicted by any witness. If the jury are satisfied that they are substantially the same, they will have no difficulty in coming to a conclusion on this point. The only remaining question is that of damages. When ascertainable, the defendants' profits are the proper rule of damages. In this case, it is also claimed that the license price and expenses of litigation should be considered. The law gives to the plaintiff his actual damages, and the amount of these is left to the discretion of the jury, under the circumstances of the case, looking to the compensation of the plaintiffs. The jury found a verdict for the plaintiffs, with two hundred dollars damages. (CIRCUIT COURT.) JUNIUS JUDSON v. WILLIAM MOORE AND CHARLES F. WIL STACH. The description of the invention is required to be full, clear, and exact, that the public may be admonished of the precise claim, that it may not be ignorantly infringed; and that when the exclusive right shall have expired, the public may be at no loss to know what the nature of the invention is, so as to make it valuable and practical. If, with the exercise of ordinary intelligence and skill, the invention could be constructed from the information given in the patent, there would be no doubt that the specification answered the requisites of the statute. Reduced to its simplest elements, the improvement of Judson consists in making an opening or openings, controlled by the governor valves of Judson v. Moore. steam engines, of gradually increasing capacity from the closed to the open position. If A. had a distinct conception of the invention as patented to B., and communicated that knowledge to B., then, in a legal point of view, A. must be considered the first inventor. Mere conversations about the practicability of an improvement, or suggestions as to the manner in which it might be carried out or accomplished, will not, of themselves, defeat the claims to originality of him who perfects the idea and secures a patent. But any information to a patentee, sufficient to enable him to construct the thing itself, would destroy the originality of the invention. But that knowledge must be definite and tangible. The evidence of the success and practical results of an invention goes more directly to the question of utility, but the jury may take it into consideration, in deciding on the novelty and originality of the invention. THIS was an action on the case, tried before the court and a jury, to recover damages for the infringement of letters patent for “improved valves for governors," granted to Junius and Alfred Judson, November 5, 1850, and reissued to Junius Judson, January 10, 1854. A portion of the specifications of the plaintiff's patent, together with the claims, was as follows: "The object of our invention is to decrease the perturbation of steam engines caused by any change in the tension of the steam, or in the resistance or load, and the more effectually to check any undue increase or decrease in the motion of the engine, than can be effected by any plan known prior to our invention; and to this end the nature of our invention consists in making the steam passage or passages controlled by the governor valve or valves, so that the area or sum of the areas of the passage or passages shall gradually increase in capacity, not only by the amount of motion which uncovers it, but so that the amount of area opened by any given amount of motion shall be gradually greater toward the fully opened end, by means of which any tendency to increase the motion of the engine shall be checked by reducing the area of the steam passage to a greater extent than would be due to the amount of motion Judson v. Moore. given to the valve, and the tendency to decrease the motion of the engine shall be checked by increasing the area of the steam passage to a greater extent than would be due to the motion of the valve alone, imparted by the governor under the change of speed of the engine. "When the governor and valve work with effect, the pressure per square inch upon the piston is less than in the boiler, and reducing the load or resistance, reduces the pressure in the cylinder, producing less resistance to the passage of steam from the boiler to the cylinder; and the area of the valve-opening necessary to pass a given amount of power or steam, is much less with the light than with the heavy load, and an increased capacity of opening from the closed to the open position of the valve, more than is due to the opening motion of the valve, is necessary, so that equal amounts of resistance being successively added (as load to the engine), shall cause the valve to open successive and regularly increasing areas, until the valve is fully open, or the load complete. "We do not wish to be understood as limiting our claim to the special form of valve-opening above described, as the form may be greatly varied, and yet act upon the principle herein specified as constituting the chief characteristic of our invention. "Nor yet to limit ourselves to the form of the aperture or apertures, as the same end may be obtained on the same principle by the joint form of the opening or openings, and the valve governing the same. "Nor do we wish to limit our invention to the making of such governor valve with the aperture or opening thereof on the principle herein specified throughout the whole range of motion, as in many instances it may be advantageously employed with the said principle acting only on a part of its range of motion, where engines are employed under such circumstances that they will not be exposed to serious perturbations above or below a certain range. Judson v. Moore. "That, we do not wish to be understood as claiming broadly the making of the apertures of governor valves of capacities varying independently of the range of motion of the valve, as the well-known throttle valve, and valves, with circular apertures, have not a constant increase or decrease of capacity proportioned to the range of motion. "But what we do claim as our invention, and desire to secure by letters patent, is making the opening or openings controlled by the governor valves of steam engines of gradually increasing capacity from the closed toward the open position, substantially in the manner and for the purpose specified. "And we also claim interposing a spring between the valve-cover and the set-screw, or its equivalent, which determines or sets the position of the face of the valve to its seat, so that the tension of the said spring shall resist the pressure of the steam on the valve cover, and thereby produce an increased flow of steam to the cylinder, substantially as specified. "And we also claim the employment of the valve-lever, adjustable to the stem of the valve, in combination with a fixed indicator, substantially as specified, for the purpose of setting the valve in any required position without opening the valve-box, as set forth. "JUNIUS JUDSON, The defendants were using a valve constructed by Cope & Hodgson, under letters patent granted to them. In the specification of this patent, the following paragraph occurred: "By providing in the box a cavity on each side of the seat, as shown at DD, figs. 1 and 3, the valve when open has its openings increased or diminished in a greater degree by a given movement than an ordinary throttle-valve, as the edges of the valve move directly away from the seat instead of parallel with it." The valves described by Judson and Cope & Hodgson Judson v. Moore. differed greatly in form, and the controversy turned upon the employment of what was called the principle of graduation. G. M. Lee and S. S. Fisher, for plaintiffs. C. B. Collier and J. L. Miner, for defendants. CHARGE OF THE COURT: A patent was issued to Junius and Alfred Judson, jointly, in November, 1850. That patent, it would appear, has since been surrendered, and on January 10, 1854, was reissued to the plaintiff, Junius Judson, alone. It purports to be a patent for a new and improved valve for governors, and he brings his action for an alleged infringement of the exclusive right granted to him by this instrument. The defendants urge several grounds of defense: First. That the patent is void from the uncertainty of its specification, in not describing the subject with sufficient perspicuity. Second. The want of originality in the invention itself. Third. That there is no utility in the patented improve ment. Fourth. That the defendants have not infringed the exclusive rights of the plaintiff, and, therefore, are not liable in this action. As to the alleged uncertainty and insufficiency of the specification in this case, I have but a remark or two to make. This defense is based upon the ground that the description of the invention is so vague and indefinite that a mechanic could not construct the improvement from the specifications. The statute is very express on this subject. It requires that every inventor shall file, in the Patent Office, a clear statement of what his invention is, and the mode by which it is to be brought into practical operation. The statement is required to be clear, full, and exact in its terms, so that a mechanic skilled in that department shall be enabled to construct it, or, if it be a composition, to compound it, and that |