As stated by the circuit court, when this patent was applied for and issued, complainants were both in the employment of the defendant, one as superintendent of defendant's mine, and the other as assayer and smelter at the mine and smelting works, each receiving a regular salary. While thus engaged they made the invention covered by the patent, and on April 19, 1871, before the application for the patent, put the improvement on the first furnace of defendant, and on April 24th, the date of the application, put it on the second furnace. These improvements were continuously used in defendant's works from that time on to the commencement of this suit. Complainant Keyes left defendant's employment September 1, 1872, and complainant Arents on November 10, 1872. They were both aware of the use of the improvement thereafter, and down to the time the suit was commenced, and it does not appear that Keyes had any communication with defendant upon that subject; but complainant Arents notified defendant's president in June, 1872, that the company could use the improvement while he remained in its employment, but that afterwards he would require the company to pay what others had to pay for its use, and, subsequently to November 10, 1872, Arents at various times made demands upon the company's secretary for payment for the use of the improvement, and in the summer of 1888 made a similar demand upon the company's president. Defendant did not contest the validity of the patent, nor deny the use of the improvement, but defended on the ground that no case for equitable jurisdiction was presented upon the facts; and that, moreover, it clearly appeared that defendant had an implied license to use the invention without compensation while complainants continued in its employment, and to use it after they left for the same royalties charged other parties; and, therefore, that the remedy of complainants was an ordinary action at law, over which, as no diversity of citizenship appeared, the circuit court had no jurisdiction.
We think from an examination of the evidence that the circuit court was entirely right in its conclusion that there was at least an implied license to use the improvement upon the same terms and royalties fixed for other parties from the time complainants left defendant's employment, while defendant was entitled to use the invention without payment of any royalties during the continuance of such employment; and, apart from that, that the decree cannot be reversed on the ground that the circuit court erred in dismissing the bill, because when it was filed complainants were not entitled to any relief resting on grounds of equity, while their remedy at law, then and thereafter, was plain, adequate, and complete.
The jurisdiction in equity was predicated upon the right to an injunction 'according to the course and principles of courts of equity.' Rev. St. § 4921. The subpoena was issued and served October 29, 1888, returnable on the first Monday in December, which was December 3, 1888. The patent expired November 28, 1888, between the day of service of subpoena and the return day, and before defendant was required to or did file its answer.
No notice of an application for a preliminary injunction was given, nor any application made therefor, nor was there any showing on the pleadings or otherwise of irreparable injury to the complainants by the continued use of the invention for 29 days after the bill was filed and before the expiration of the patent. Such a contention, after 17 years of use by appellee with appellants' knowledge, would have been absurd, and, even if appellants had applied for a preliminary ij unction before the return day, the court would have been justified in refusing to award it. Obviously, the laches of appellants was such, upon their own showing (for the delay was unexplained), as to disentitle them to a preliminary injunction, as ruled by Mr. Justice Brewer, when circuit judge, in McLaughlin v. Railway Co., 21 Fed. 574, and by Judge Blodgett in American Cable Ry. Co. v. Chicago City Ry. Co., 41 Fed. 522. See, also, Keyes v. Refining Co., 31 Fed. 560.
This record discloses that the invention had been used for more than 17 years with the knowledge and assent of appellants, and without any complaint on their part, except that appellee had not paid royalties after complainants quit its employment. This being so, the case clearly falls within Root v. Railway Co., 105 U.S. 189; Clark v. Wooster, 119 U.S. 322, 7 Sup. Ct. 217; and Lane & Bodley Co. v. Locke, 150 U.S. 193, 14 Sup. Ct. 78; and the decree was fully justified.