Syllabus. repealed law only in relation to violations committed after the passage of the repealing law. If the decision above mentioned was made known to the legislature, it is not impossible but that a doubt might have existed whether the patent was thereby rendered void ab initio, or from the time of rendering the judgment; and if the latter, then the proviso would afford a protection against all preceding violations. But, whatever might be the inducements with the legislature to limit the proviso under consideration, as we find it, this court cannot introduce a different proviso, totally at variance with it in language and intention. It is the unanimous opinion of this court, that the act passed in January, 1808, entitled "An act for the relief of Oliver Evans," ought not to be construed as to exempt from either treble or single damages the use, subsequent to the passage of the said act, of the machinery therein mentioned, which was erected subsequent to the expiration of the original patent and previous to the passage of the said act. Which opinion is ordered to be certified to the Circuit Court for the District of Virginia. EVANS v. EATON. (3 Wheaton, 454.) 1. Under the 6th section of the Patent Law of 1793, ch. 156, the defendant pleaded the general issue, and gave notice that he would prove at the trial that the machine, for the use of which, without license, the suit was brought, had been used previous to the alleged invention of the plaintiff, in several places which were specified in the notice, or in some of them, "and also at sundry other places in Pennsylvania, Maryland, and elsewhere in the United States." The defendant having given evidence as to some of the places specified, offered evidence as to others not specified: Held, That this' evidence was admissible. But the powers of the court, in such a case, are sufficient to prevent, and will be exercised to prevent, the patentee from being injured by surprise. 2. Testimony, on the part of the plaintiff, that the persons, of whose prior use of the machine the defendant had given evidence, had paid the plaintiff for licenses to use the machine since his patent, ought not to be absolutely rejected, though entitled to very little weight. 3. Quære. Whether, under the general Patent Law, improvements on different machines can be comprehended in the same patent, so as to give a right to the exclusive use of several machines separately, as well as a right to the exclusive use of those machines in combination? 4. However this may be, the act of the 21st of January, 1808, ch. 117, "for the relief of Oliver Evans," authorizes the issuing to him of a patent for his invention, discovery, and improvements in the art of manufacturing flour, and in the several machines applicable to that purpose. Statement of the case. 5. Quære. Whether Congress can constitutionally decide the fact that a particular individual is an author or inventor of a certain writing or invention, so as to preclude judicial inquiry into the originality of the authorship or invention? 6. Be this as it may, the act for the relief of Oliver Evans does not decide that fact, but leaves the question of invention and improvement open to investigation under the general Patent Law. 7. Under the sixth section of the Patent Law, ch. 156, if the thing secured by patent had been in use, or had been described in a public work, anterior to the supposed discovery, the patent is void, whether the patentee had a knowledge of this previous use or description or not. 8. Oliver Evans may claim, under his patent, the exclusive use of his inventions and improvement in the art of manufacturing flour and meal, and in the several machines which he has invented, and in his improvement on machines previously discovered. But where his claim is for an improvement on a machine, he must show the extent of his improvement, so that a person understanding the subject may comprehend distinctly in what it consists. 9. The act for the relief of O. E. isingrafted on the general Patent Law, so as to give him a right to sue in the Circuit Court for an infringement of his patent-rights, although the defendant may be a citizen of the same State with himself. ERROR to the Circuit Court for the District of Pennsylvania. This was an action brought by the plaintiff in error against the defendant in error, for an alleged infringement of the plaintiff's patent-right to the use of his improved hopper-boy, one of the several machines discovered, invented, improved, and applied by him to the art of manufacturing flour and meal, which patent was granted on the 22d January, 1808. The defendant pleaded the general issue, and gave the notice hereafter stated. The verdict was rendered, and judgment given thereupon for the defendant in the court below; on which the cause was brought, by writ of error, to this court. At the trial in the court below, the plaintiff gave in evidence the several acts of Congress entitled, respectively, "An act to promote the progress of useful arts, and to repeal the acts heretofore made for that purpose;" "An act to extend the privilege of obtaining patents, for useful discoveries and inventions, to certain persons therein mentioned, and to enlarge and define penalties for violating the rights of patentees;" and "An act for the relief of Oliver Evans;" the said Oliver's petition to the Secretary of State for a patent, and the patent thereupon granted to the said Oliver, dated the twentysecond day of January, in the year 1808; and further gave in evidence, that an agent for the plaintiff wrote a note to the defendant, in answer to which he called on the agent at Chambersburg, at the house of Jacob Snyder, on the ninth of August, 1813; there were a number of millers present: the defendant then told the agent that Statement of the case. he had got Mr. Evans's book, a plate in the Millwright's Guide, and if the agent would take forty dollars the defendant would give it him; the defendant said that his hopper-boy was taken from a plate in Mr. Evans's book; he said he would give no more, alleging that the hundred dollars the agent asked was too much; that the stream on which his mill was, was a small head of Conogocheage. The agent then declared that, if the. defendant would not pay him by Monday morning, he would commence a suit in the Circuit Court. The plaintiff further gave in evidence, that another agent for the plaintiff was in the defendant's mill on the second of November, 1814, and saw a hopper-boy there, on the principles and construction of the plaintiff's hopper-boy. This witness had heard that a right was obtained under Pennsylvania, but did not know of any rights under Pennsylvania sold by the plaintiff, and did not know that it was erected in any mill after the patent under Pennsylvania. The defendant's hopper-boy had an upright shaft, with a leading arm, in the first place, and a large arm inserted with flights, and leading lines, and sweepers; a little board for the purpose of sweeping the meal in the bolting hoppers, and spreading it over the floor; a balance weight, to'cause the arms to play up and down lightly over the meal. The leading arms are about five feet long, and seem to be in proportion, the arm about fourteen, and the length of the sweep about nine inches. And the defendant, having previously given the plaintiff written notice that upon the trial of the cause the defendant would give in evidence, under the general issue, the following special matter, to wit: "1st. That the improved hopper-boy, for which, inter alia, the plaintiff in his declaration alleges he has obtained a patent, was not originally discovered by the patentee, but had been in use anterior to the supposed discovery of the patentee, in sundry places, to wit, at the mill of George Fry and Jehu Hollingsworth, in Dauphin county, Pennsylvania; at Christian Stauffer's mill, in Warwick township, Lancaster county, State of Pennsylvania; at Jacob Stauffer's mill, in the same county; at Richard Downing's mill, in Chester county, Pennsylvania; at Buffington's mill, on the Brandywine; at Daniel Houston's mill, in Lancaster county, Pennsylvania; at Henry Stauffer's mill, in York county, Pennsylvania; and at Dihl's mill, in the same county, or at some of the said places, and also at sundry other places in the said State of Pennsylvania, the State of Maryland, and elsewhere in the United States. 2d. That the patent given to the plaintiff, as he alleges in his declaration, is more extensive than his discovery or invention: for that certain parts of the machine in said patent, called an improved hopper-boy, and which the plain T Statement of the case. .tiff claims as his invention and discovery, to wit, the upright shaft, arms, and flights, and sweeps, or some of them, and those parts by which the meal is spread, turned, and gathered at one operation, and also several other parts, were not originally invented and discovered by him, but were in use prior to his said supposed invention or discovery, to wit, at the places above mentioned, or some of them. 3d. That the said patent is also more extensive than the plaintiff's invention or discovery: for that the application of the power that moves the mill or other principal machine to the hopper-boy is not an original invention or discovery of the plaintiff, but was in use anterior to his supposed invention or discovery, to wit, at the places above mentioned, or some of them. 4th. That the said patent is void, because it purports to give him an exclusive property in an improvement in the art of manufacturing meal by means of a certain machine termed an improved hopper-boy, of which the said plaintiff is not the original inventor or discoverer, parts of the machine in the description thereof referred to by the patent having been in use anterior to the plaintiff's said supposed discovery, to wit, at the places above mentioned, or some of them; and the said patent and description therein referred to contains no statement, specification, or description by which those parts, so used as aforesaid, may be distinguished from those of which the said plaintiff may have been, the inventor or discoverer, protesting at the same time that he has not been the inventor or discoverer of any of the parts of the said machine. 5th. That the improved elevator described in the declaration, or referred to therein, was not originally discovered by the plaintiff, but was, anterior to his said supposed discovery or invention, described in certain public works, or books, to wit, in Shaw's Travels; in the first volume of the Universal History; in the first volume of Mormer's Husbandry; in Ferguson's Mechanics; in Bossuet's Historie des Mathematiques; in Wolf's Cours des Mathematiques; in Desagulier's Experimental Philosophy, and in Proney's Architecture Hydraulique, or some of them. 6th. That the said patent is more extensive than the invention or discovery of the plaintiff, because certain parts of the machine called an improved elevator were, anterior to the plaintiff's said supposed invention or discovery, described in certain public works or books, to wit, the works or books above mentioned, or some of them; and that the said patent is void, because it neither contains nor refers to any specification or description by which the parts so before described in the said public works may be distinguished from those parts of which the plaintiff may be the inventor or discoverer, protesting, at the same time, that he has not been the inventor or Statement of the case. discoverer of any of the parts of the said machine,"-gave in evidence the existence of hopper-boys, prior to the plaintiff's alleged discovery, at sundry mills in the State of Pennsylvania mentioned in the said notice; and further offered to give in evidence the existence of hopper-boys, prior to the plaintiff's alleged discovery, at sundry other mills in the State of Pennsylvania not mentioned in the said notice; and the counsel for the plaintiff objected to the admission of any evidence of the existence of hopper-boys in the said mills not mentioned in the said notice. But the court decided that such evidence was competent and legal. To which decision the counsel for the plaintiff excepted. The plaintiff, after the above evidence had been laid before the jury, offered further to give in evidence, that certain of the persons mentioned in the defendant's notice as having hopper-boys in their mills, and also certain of the persons not mentioned in the said notice, but of whom it has been shown by the defendant that they had hopper-boys in their mills, had, since the plaintiff's patent, paid the plaintiff for license to use his improved hopper-boy in the said mills respectively. But the counsel for the defendant objected to such evidence as incompetent and illegal, and the court refused to permit the same to be laid before the jury. To which decision the plaintiff's counsel excepted. The court below charged the jury that the patent contained no grant of a right to the several machines, but was confined to the improvement in the art of manufacturing flour by means of those machines; and that the plaintiff's claim must, therefore, be confined to the right granted, such as it was. That it had been contended that the schedule was part of the patent, and contained a claim to the invention of the peculiar properties and principles of the hopper-boy as well as the other machines. But the court was of opinion that the schedule is to be considered as part of the patent, so far as it is descriptive of the machines, but no farther; and even if this claim had been contained in the body of the patent, it would have conferred no right which was not granted by that instrument. The court further proceeded to instruct the jury that the law authorized the President to grant a patent for the exclusive right to make, construct, use, and vend to be used any new and useful art, machine, manufacture, or composition of matter, or any new and useful improvement in any art, machine, &c., not known or used before the application. As to what constitutes an improvement, it is declared that it must be in the principle of the machine, and that a mere change in the form or proportions of any machine shall not be deemed a discovery. Previously to obtaining the patent, the appli |