Keplinger V. Such a contract, connected with evidence from which the jury might 1825. legally infer, either that the machine which was to be employed in the manufacture of the patented article was owned wholly or in part by the defendant, or that it was hired to the defendant for six months, under colour of a sale of the articles to be manufactured with it, and with intent to invade the plaintiff's patent right, would amount to a breach of his right. ERROR to the Circuit Court of Maryland. De Young. This cause was argued by Mr. Webster and March 15th. Mr. Sergeant, for the plaintiff, and by the Attorney General, for the defendant. Mr. Justice WASHINGTON delivered the opinion March 17th. of the Court. This was a suit commenced by the plaintiff, Keplinger, in the Fourth Circuit for the District of Maryland, against the defendant, for the violation of the plaintiff's patent right, secured to him according to law, in a certain new and useful improvement, to wit, a machine for making watch chains, &c. The third count in the declaration, upon which alone this cause has been argued, is in the usual form, charging the defendant with having unlawfully used the said improvement without the consent of the plaintiff first had and obtained in writing. The defendant pleaded the general issue, and gave notice to the plaintiff that he should deny that the exclusive right of using the improvement mentioned in the declaration, was vested in the plaintiff, or that he was the original and first inventor of the said improvement, and that he should give evidence to establish those facts. 1825. Keplinger V. At the trial, the plaintiff read in evidence the letters patent duly granted, bearing date the 4th of May, 1820, and proved, that he was the true De Young and original inventor of the machine specified in the patent, and that the defendant, together with John Hatch and John C. Kirkner, did use the said machine in the making of watch-chains from steel, from the 4th of May till some time in the month of December, 1820. The defendant, in order to prove that any concern or connexion which he had with the said Hatch and Kirkner, in the making of watchchains, by means of the said machine, was merely as a purchaser of watch-chains from them under the following contract, produced and gave the same in evidence. The agreement referred to, bearing date the 3d of May, 1820, is between M. De Young, and J. Hatch and J. Kirkner, and witnesses, "that the said Hatch and Kirkner do hereby engage and obligate themselves to manufacture and deliver to M. De Young, or at his store in said city, not less than three gross, but as many as five gross, of wire watch chains, agreeably to a sample to be deposited with T. Barly, (if practicable to manufacture so many,) in each week, from the date hereof, for the term of six months, one half of which number to be with turned slides, and the other half wire slides; the whole number to be four strands, if the said De Young so choose; but he is to have the privilege of directing the description to be furnished, that is to say, what number of four, five, six, or eight strands; the prices of Keplinger V. De Young. which to be as follows: four strands, two dollars 1825. per dozen; six strands, two dollars sixty-six cents and two thirds per dozen, and eight strands at the rate of three dollars thirty-three cents per dozen; said Hatch & Kirkner to devote their whole time and attention to said manufactory, and neither to sell, barter, nor dispose of, in any manner, or way, or means whatever, of any goods of the description herein before described, or which may, in any manner or way whatsoever, interfere with the exclusive privilege herein before granted, but will faithfully manufacture for said De Young, and none other, as far as five gross of chains per week, if practicable, and not less than three gross per week, at the prices herein before stipulated, and payable as follows: one half in cash at the end of every week, for the total number delivered within the week, and the other half in said De Young's promissory note, payable at sixty days from the date thereof. And the said De Young, on his part, doth hereby promise to receive from the said Hatch & Kirkner, such quantity of watch-chains answering the description of the sample, as it may be in their power to manufacture, not exceeding five gross per week, reserving to himself the privilege of directing what proportion thereof shall be four, six, or eight strands, and pay for the same weekly in the following manner, viz. the one half amount of week's delivery in cash, the other half in a note at sixty days, the same to be settled for weekly, in manner aforesaid, if required." The defendant also gave evidence to prove Keplinger 1825. that all the connexion he ever had with the said - Hatch & Kirkner, relative to watch-chains made by them with the said machine or otherwise, was De Young merely as a purchaser of such chains from them, under and in pursuance of the said contract. V. The plaintiff then proved, that, at the time of making the said contract, the defendant was fully apprized of the existence of the machine described and specified in the patent, and of its prior and original invention by the plaintiff, and of the intention of the plaintiff to obtain the said patent; and that the said contract was made with a view to the employment by the said Hatch & Kirkner, in the manufacture of watch-chains, of a machine precisely similar to that invented by the plaintiff, after the plaintiff should have obtained his patent; and that a machine precisely similar to that invented by the plaintiff was employed by the said Hatch & Kirkner in the manufacture of watch-chains by them under the / said contract, and with the knowledge and consent of the defendant during the whole period aforesaid, he and they having received notice, on the 5th of May, 1820, of the plaintiff's patent; and that the watch-chains so manufactured by Hatch & Kirkner, during the whole of the said period, were delivered by them to the defendant, and by him received, under and in conformity with the said contract. Upon this evidence, the Court, at the request of the defendant's counsel, instructed the jury, that the plaintiff was not entitled to a verdict on the first and second counts in his declaration, because the acts which they charge, if true, constitute no offence against the plaintiff's patent. And that, if the jury should be of opinion, on the evidence, that the plaintiff is the sole and original inventor of the whole machine; and that the defendant had no other connexion with Hatch & Kirkner with regard to these chains, than that which arose from his said contract with them, under which he procured the chains to be made by Hatch & Kirkner, and sold them when so made; and that the said contract is a real contract; then these acts constituted no breach of the plaintiff's patent-right on the part of De Young, and that the verdict must be for the defendant; and that this legal aspect would not be changed, although the defendant may, on any occasion, have supplied, at the cost of Hatch & Kirkner, the wire from which the chains so manufactured were made. To this instruction the plaintiff's counsel took a bill of exceptions, and a verdict and judgment having been rendered for the defendant, the cause is brought into this Court by a writ of error. 1825. Keplinger V De Young. der the bill of The only question which is presented by the Question unbill of exceptions to the consideration of this exceptions. Court is, whether the Court below erred in the instruction given to the jury; and this must depend upon the correct construction of the 3d section of the act of Congress, of the 17th of April, 1800, c. 179. which enacts, "that where any patent shall be granted, pursuant to |