ment to account and pay the royalty nor the parties of the second part shall, etc., neglect, clause of forfeiture for non-performance con- etc., that this assignment and transfer shall tained in that instrument reduced them to the thereafter be void and of no effect," etc. This position of licensees. The agreement to ac- is undoubtedly sufficient to charge purchasers count and pay formed part of the consideration with notice of the execution of the supplementof the assignment, and was in effect an agree-ary agreement, and possibly of its provisions, ment to pay at a future time a sum to be determined by the number of articles made and sold. For the non-payment or other non-performance a forfeiture might be enforced as for condition broken, but until it was enforced the title granted remained in the assignees. The supplementary agreement contained a provision that Littlefield should sue infringers "in his own name or otherwise," and also defend all suits against Treadwell & Perry for alleged infringements of other patents by the use of his, and this it is alleged is evidence of the intention of the parties to make the grant effective only as a license. It needs only a slight examination of that clause in the contract, however, to become satisfied that it was intended only as a provision for placing on Littlefield the 221*] costs and expenses of all such litigation, as well as all damages for infringements growing out of the use of the inventions by the assignees. The suits were to be prosecuted in his name, or otherwise, as circumstances should require, and he was to be at all the costs and expenses of maintaining his patents. That is the extent of the provision. Upon the argument, the reservation of the right to use the principle of the patent and inventions in the manufacture of furnaces seemed to be relied upon with more confidence as establishing this claim on the part of the defendants. All agree that the intention of the parties, when ascertained by an examination of both the instruments, must govern in this action where only the parties themselves are interested. There are no intervening innocent third persons. Jagger, the partner of Littlefield, who is codefendant with him, is charged with full notice of the rights of Treadwell & Perry, and others claiming under them. but it falls far short of indicating an intention of the parties, by anything contained in the unrecorded instrument, to limit or defeat the assignment made in consideration of it. The most that can be inferred from such language is, that the parties had stipulated between themselves, not as to the legal effect of the recorded instrument, but as to their obligations or equitable rights under it. We think, therefore, that Treadwell & Perry were the assignees of Littlefield within the meaning of the patent laws, and that they and those claiming under them may sue in the circuit courts to prevent an infringement upon their rights. But even if they are not technically assignees, we think this action is, nevertheless, maintainable. They certainly had the exclusive right to the use of the patent for certain purposes within their territory. They thus held a right under the patent. The claim is that this right has been infringed. To determine the suit, therefore, it is necessary to inquire whether there has been an infringement, and that involves a construction of the patents. The Act of Congress provides "That all actions, suits, controversies and cases arising under any law of the United States granting or confirming to inventors the exclusive right to their inventions or discoveries shall be originally cognizable, as well in equity as at law, in the circuit courts, etc." An action which raises a question of infringement is an action arising "under the law," and one who has the right to sue for the infringement may sue in the circuit court. Such a suit may involve the construction of a contract as well as the patent, but that will not oust the court of its jurisdiction. If the patent is involved it carries with it the whole case. *A mere licensee cannot sue strangers [*223 who infringe. In such case redress is obtained through or in the name of the patentee or his assignee. Here, however, the patentee is the infringer, and as he cannot sue himself, the licensee is powerless, so far as the courts of the United States are concerned, unless he can sue in his own name. A court of equity looks to substance rather than form. When it has jurisdiction of parties it grants the appropriate relief without regard to whether they come as In this case the person plaintiff or defendant. who should have protected the plaintiff against all infringements has become himself the infringer. He held the legal title to his patent in trust for his licensees. He has been faithless to his trust, and courts of equity are always open for the redress of such a wrong. This wrong is an infringement. Its redress involves a suit, therefore, arising under the patent laws, and of that suit the circuit court has jurisdiction. It is a significant fact that the agreement was executed in two parts. Ordinarily the whole of such a contract is embodied in a single instrument. Another important fact is, that only one of the parts is recorded, and that the one which, taken by itself, places the title in Treadwell & Perry. The record is intended for the benefit of the public. Bona fide purchasers look to it for their protection. The record of the grant alone, therefore, furnishes the strongest evidence of the intention of the parties to give effect to the two instruments as an assignment. It is true that in the recorded part reference is made to the other, but the manner of the reference is not such as to indicate that the unrecorded part contained anything to defeat the title granted by that which was recorded. The language is, "In consideration of $1, and of the agreements herein contained on the part of the parties of the second part, and of the agreements contained in a certain agreement this day executed between the parties hereto, and bearing even date here- It is next asserted that the complainant has with, hath, and by these presents doth assign, not by his proof shown himself to be the asetc." And again; "It is expressly understood signee of Treadwell & Perry. They, on the and agreed between the said parties that in case 25th of March, 1862, assigned all their in222] said party of the first part shall well terest to George W. Sterling. He became disand faithfully keep and perform all the agree- satisfied with his purchase and, by agreement ments herein, and in the aforesaid agreement of parties, the sale was canceled, he giving bearing even date herewith contained, and said ' effect to the cancellation by executing a # re assignment to Treadwell & Perry, bearing date June 2, 1862. Under date of April 7, 1862, Treadwell & Perry executed another assignment to one Dickey. Both the re-assignment from Sterling and the assignment to Dickey were left at the Patent Office for record on the 26th June, 1862, and on the 2d July, Dickey assigned to Mary J. Perry, in whose name the suit was commenced. It is now claimed that this proof shows title in Treadwell & Perry, inasmuch as Sterling reassigned to them after they had assigned to Dickey. Mrs. Perry was the wife of John S. Perry, one of the firm, and he is now a party to the suit, having upon her death succeeded to all her rights, as trustee under her will. Treadwell, the other member of the firm, has been several times in the progress of the cause 224*] examined as a witness, and has testified that Dickey became the owner of the patents under a transfer to which he consented. It is clear, therefore, that Mrs. Perry at the commencement of the action was in equity, if not in law, the owner of whatever had been assigned by Littlefield, and that if Treadwell & Perry had the legal title, they held it in trust for her, and will be estopped by a decree in her favor from setting up as against Littlefield any beneficial interest under it. At an carlier stage of the proceedings it might have been proper to make Treadwell a party, but upon the case as it now stands no possible harm can result to the defendants from a decree against them in his absence. complete combustion of them both." Upon this application a patent was issued January 20, 1854. All the patents outstanding, and the subject of this controversy, are admitted to be re-issues of this or improvements upon it. Littlefield and his co-defendants do not deny that they have used the patents issued after January, 1854, and if the title to them passed under the assignment of April, 1853, it is admitted that such use is an infringement and that the complainant is entitied to a decree. The simple question, then, presented for our consideration is as to the effect to be given to this assignment. It is well settled that a recorded assignment of a perfected invention, made before a patent has issued, carries with it the patent when issued (Gayler v. Wilder, 10 How., 477), and that re-issues are not patents for new inventions, but amendments of old patents. If a reissue is obtained with the consent of an assignee, it inures at once to his benefit; if without, he has his election to accept or reject it. The parties have themselves agreed that the invention of 1852 is an improvement upon the patent of 1851. In the grant the patent is described as being "For a coal burner, so constructed as to produce combustion of the inflammable gases of anthracite coal," and the application as being for an improvement upon the patent. It is true that the application is not referred to by its date, but there can be no doubt as to its identity, because the language adopted to describe the patent is not that of the This brings us to a consideration of the mer- claim in the patent itself, but of the applicaits of the case. On the 15th April, a patent tion of 1852. Besides, the application is said to was issued to Littlefield for a certain improve- be then pending, and it is not pretended tnat ment in cooking stoves, and on the 30th Decem- Littlefield had any other on file in the Patent ber, 1852, he filed in the Patent Office his appli- Office at that date. This relieves us [*226 cation for another improvement in stoves, de- from an examination of the specifications in the vised "For the purpose of economizing and patent and application, for the purpose of as burning the gases generated by the combustion certaining whether in point of fact the one was of anthracite coals." On the 5th April, 1853, an improvement upon the other. Littlefield he executed the grant and supplementary agree-having agreed that it was, and having induced ment already referred to. In the grant, after Treadwell & Perry to purchase by reason of reciting that he held a patent bearing date this agreement, cannot now deny it. April 15, 1851, "For a coal burner so constructed as to produce combustion of the inflammable gases of anthracite coals," and that he had "made application to the Patent Of fice at Washington for letters patent securing to him a certain improvement in the invention so as aforesaid patented to him," and that such application was then pending, he proceeded to assign all the right, title and interest which he then had, or might thereafter have, "In or to the aforesaid inventions, improvement and patent, or the patent or patents that may be granted for said inventions or any improve ment therein, and on any extension or extensions thereof, within and throughout the district, etc., for and during the term for which the aforesaid letters natent were granted, and the terms for which any patent for the aforesaid improvement or any improvement or improvements thereof may be granted, etc." 225*] The application of *December 30, 1852, was rejected at the Patent Office, and finally withdrawn by Littlefield on the 22d day of July, 1853, he at the same time filing another application for "a new and useful improvement in stoves," so devised as "to burn the gaseous or more inflammable elements of the coal in contact with its more refractory portions, and thus secure a It is clear, also, that the idea which Littlefield had in mind, and which he was endeavoring by his devices to make practically useful. was greater economy in the use of the inflanımable gases of coal to produce combustion. It is not important in this suit that the patent, which had then been obtained, was not in fact suited for that purpose. It is sufficient that it was intended to be so. The subsequent devices, better adapted to the end to be accomplished, may, therefore, properly be regarded as improvements upon the original invention. They produce a stove doing the same thing which the first was intended to do, but doing it better. This is the proper office of an improvement. The assignment in this case, by its express terms, covers all improvements in the original patent or the invention described in the application of 1852. It carried with it the legal title to the existing patent. If one had been issued upon the application, that, too, would have inured to the benefit of the assignee, because in that case it would have been the assignment of a perfected invention. Without considering whether the invention upon which the patent of 1854 issued, was not, in fact, the same to all intents and purposes as that of 1852, it is sufficient for the purposes of this case that it was an improvement upon it or perhaps more properly, that invention perfected. An | Littlefield, and that he is entitled to recover of assignment of an imperfect invention, with all the defendants the profits they have made out improvements upon it that the inventor may of these infringements, upon his rights. So far make, is equivalent in equity to an assign- there is no error in the court below. ment of the perfected results. The assignment in this case being such an one, the assignees became in equity the owners of the patent granted upon the perfected invention; that is to say, of the patent of 1854. Littlefield took the legal title in trust for them, and should convey. Courts of equity in proper cases consider that as done which should be. If 227*] *there exists an obligation to convey at once, such courts will oftentimes proceed as if it had actually been made. There is here no attempt to obtain the specific performance of a contract, but to restrain this patentee from infringing upon rights which, in a court of equity, he is deemed to have assigned. In other words, this complainant is in equity an assignee, and entitled to protection as such. If the assignment in precisely its present form had been executed after the last re-issue was granted, we think it would hardly be claimed that the legal title to all the present outstanding patents did not pass with it. What such an assignment could do in respect to legal titles this has done in respect to such as are equitable. The contest is now between an assignor in equity and his assignee. A court of equity will in such a case give the same effect to an equitable title that it would to one that was legal. We now come to the decree itself. The plaintiff is entitled, as has been seen, to recover of the defendants the profits they have made from the use of the several inventions within the assigned territory; but the decree directed an account of all the profits, gains and advantages which the said defendants, or either of them, have received or which have arisen or accrued to them or either of them from the manufacture, use or sale, of stoves within the States of New York and Connecticut, embracing the improvements described in and covered by the said letters patent and the re-issues thereof, or any of them." An account stated upon these principles has been approved by the court in the decree appealed from. After The decree is, as we think, too broad. the interlocutory decree below settling the principle of the accounting, the case of Mowry v. Whitney, 14 Wall., 620, 20 L. ed., 860. was decided in this court. It was there held that the question to be determined in such a case as this was, "What advantage did the defendant derive from using the complainant's invention over what he had in using other processes then open to the public, and adequate to enable him to obtain an equally beneficial result? *The [*229 fruits of that advantage are his profits." such profits he is compelled to account as damages. For It is next contended that the assignment in this case was forfeited before the commenceHere the order is to account for all profits rement of this action, because of the failure of ceived from the manufacture, etc., of stoves Treadwell & Perry to perform its conditions. embracing the improvements covered by any of There is no proof that the royalty on the the patents. This would cover all the profits stoves made and sold before the action was com-made upon the stove having in it any one of the menced was sufficient to discharge that part of the debt due from Littlefield to Treadwell & Perry, which was first to be paid out of it before anything was payable to him, and there could be no forfeiture for neglect to make and sell, until after reasonable notice of the default. No such notice is proven or even claimed. It is next insisted that if the plaintiff claims the benefit of the last re-issues, he puts it out of his power to have damages for infringements previous to their date. The original bill in this cause was filed August 27, 1862. Everthing since that time has been done pendente lite. The first re-issue was granted November 19, 1861, and the first patent for an improvement on the patent of 1854 was issued on the 27th June previous. All in the way of re-issues or improvements except these has been done pending the suit. The litigation gathers to its harvest the fruits of the labors of Littlefield and his associates during its pendency. His 228*] *infringement and that of his co-defendant, Jagger, claiming under him, commenced in 1862, only a short time before the action was commenced. The question presented by this objection is, therefore, comparatively unimportant; but if it were not, the result would be the same. For as Littlefield held his patents all the time in trust for these assignees to the extent of the territory they owned, he must account to them for the profits he has made by the unlawful use of the trust property. We are, therefore, clearly of the opinion that the complainant is in equity the assignee of improvements patented. The true inquiry is, This reverses the decree. Many exceptions were taken to the master's report. Some were as to the matters of form, and others were directed to the principles of the accounting as settled by the decree. It is unnecessary to consider these further. Another account may dispose of them all. The circuit court, however, in rendering its final decree, added interest to the amount found by the master to be due upon the account for profits. In Mowry v. Whitney, supra, it was held that interest is not allowable in such cases except under peculiar circumstances. The testimony thus far presented in this case does not, in our opinion, justify such an allowance. It will be for the court to determine, upon the coming in of the new report, accompanied by other evidence, whether the conduct of the de230*] fendants has been such as to *subject them to liability in this particular. Profits actually realized are usually, in a case like this, the measure of unliquidated damages. Circumstances may, however, arise which would justify the addition of interest in order to give complete indemnity for losses sustained by wilful infringements. sections of the land granted, a portion of them to the contractors who graded the road, which sections were selected within a continuous twenty miles of the line of the road. The selections were approved by the Secretary of the Interior, and the sections were certified by him to the State. Those, however, selected were not from lands lying along the eastern end of the road, as they might have the Company did a large amount of grading, it been, but from lands lying further west. Although never completed any part of the road, and in March, 1860, the Legislature of Iowa resumed the lands, interests, rights, powers and privileges conferred upon the Company, and repealed the clauses of the Act granting them; held, 1. That the Act of Congress authorized a sale of one hundred and twenty sections in advance of the construction of any part of the road; that it was only as to the sale of the remaining sections that the provision requiring a previous completion of twenty miles applied. 2. That there was no restriction upon the State as to the place where the one hundred and twenty sections should be selected along the line of the The decree of the Circuit Court is reversed, to the extent hereinbefore indicated, and the cause remanded, with instructions to take a new account of profits and proceed in accord-road, except that they should be included within a ance with this opinion. THE CEDAR RAPIDS & MISSOURI RIVER RAILROAD COMPANY and The Iowa Railroad Land Company, Plffs. in Err., v. MILTON COURTRIGHT. (See S. C., 21 Wall., 310-316.) Act granting land to Iowa in aid of railroads -proceedings under-sales in advance of construction of road-selections of landtitle of railroad-title of its grantees. continuous length of twenty miles on each side; and that they might be selected from lands adjoining the eastern end of the road, or the western end, or along the central portion. 3. That the Company mentioned in the Act of the State of July 14, 1856, took the title and interests of the State, upon the terms, conditions and restrictions expressed in the Act of Congress, and that the further conditions as to the completion of the road, imposed by the State, were conditions subsequent. 4. That the purchasers of the one hundred and twenty sections took a good title to the property, although no part of the road was constructed at the time. [No. 159.] Submitted Jan. 28, 1875. Decided Feb. 8, 1875. I The case is fully stated by the court. This is an action for the possession of certain real property situated in the State of Iowa, being part of the lands embraced in the Act of Congress of May 15, 1856, and Act entitled "An Act Making a Grant of Land to the State of Iowa in Alternate Sections to Aid in the Construction of Certain Railroads in Said State." 11 Stat. at L., 9. That Act granted to the State, for the purpose of aiding in the construction of a railroad from Lyons City, in that State, northwesterly to a point of intersection with the main line of the Iowa Central Air Line Railroad, near Maquoketa, and thence to the Missouri River, alternate sections of land, designated by odd numbers, for six sections in width on each side of the road, to be selected within fifteen miles therefrom, with a provision that if it should appear, when the route of the road was definitely fixed, that the United States had sold, of the lands thus designated, any sections or parts of sections, or the right of preemption had attached to them, other lands of equal quantity in alternate sections, might be selected from adjoining lands of the United States. And the Act declared that the lands thus granted should be exclusively applied *On the 15th of May, 1856, Congress passed an Act entitled "An Act Making a Grant of Land to the State of Iowa, in Alternate Sections, to Aid in the Construction of Certain Railroads in Said State." 11 Stat. at L., 9. That Act granted to the State, for the purpose of aiding in the construction of a railroad between certain specified places, alternate sections of land, designated by odd numbers, for six sections in width on each side of the road, to be selected within fifteen miles therefrom. And the Act declared that the lands thus granted should be exclusively applied to the construction of the road, and be subject to the disposal of the Legislature for that purpose and no other, and only in the manner following, that is to say a quantity of land, not exceeding one hundred and twenty sections, and included within a continuous length of twenty miles of the road, might be sold; and when the Governor of the State should certify to the Secretary of the Interior that any continuous twenty miles of the road were completed, then another like quantity of the land granted might be sold, and so from time to time until the road was completed. The State of Iowa, by Act of its Legislature, passed on the 14th of July, 1856, accepted the grant thus made and provided for the execution of the trust. By that Act, the State granted to The Iowa Central Air Line Railroad Company, a corporation created by its Legislature for the construction of the railroad, "the lands, interests, rights, powers and privileges" conferred by the Act of Congress, upon the express condition, however, that in case the Company should fail to have completed and equipped seventy-five miles of the road within three years from the first day of December then next following, and thirty miles in addition in each year thereafter for five years, and the remainder of its whole line in one year thereafter, or on the first of December, 1865, then it should be competent for the State to resume all rights to the lands conferred by the Act remaining undisposed of by the Company. The Company accepted the grant from the State, with its conditions, and, immediately thereafter, caused a survey and location of to the line of the road to be made, a map of which subject to the disposal of the Legislature was filed in the proper offices in the State and at for that purpose and no other, and only Washington. During the years 1857 and 1858, the Company performed a large amount of grading in the manner following, that is to say: upon the road, and sold one hundred and twenty a quantity of land, not exceeding one hundred and twenty sections and included with *Headnotes by Mr. Justice FIELD. the construction of the road and be in a continuous length of twenty miles of the road, might be sold; and when the Governor of the State should certify to the Secretary of the Interior that any continuous twenty miles of the road were completed, then another like quantity of the land granted might be sold, and so, from time to time, until the road was completed; and that if the road was not completed within ten years, no further sales should be made, and the lands unsold should revert to the United States. The State of Iowa, by Act of its Legislature, 313*] passed on the 14th of July, 1856, accepted the grant thus made and provided for the execution of the trust. Laws of 1856 of Iowa, p. 1. By that Act, the State granted to the Iowa Central Air Line Railroad Company, a Corporation created by its Legislature for the construction of the railroad, “the lands, interests, rights, powers and privileges" conferred by the Act of Congress, upon the express condition, however, that in case the Company should fail to have completed and equipped seventy-five miles of the road within three years from the first day of December then next following, and thirty miles in addition in each year thereafter for five years, and the remainder of its whole line in one year thereafter, or on the first of December, 1865, then it should be competent for the State to resume all rights to the lands remaining undisposed of by the Company, and all other rights conferred by the Act. The Company accepted the grant from the State, with its conditions, and immediately thereafter caused a survey and location of the line of the road to be made, a map of which was filed in the proper offices in the State and at Washington. During the years 1857 and 1858, the Company performed a large amount of grading upon the road, principally between Lyons and Maquoketa. The plaintiff was one of the contractors who did the grading, and he received, in payment for his work, construction bonds and land scrip of the Company. These were afterwards surren dered and, in consideration thereof, the land in controversy was sold and conveyed by the Company to him. The land thus conveyed was a part of the first and only one hundred and twenty sections sold by the Company, and these sections were selected within a continuous twenty miles of the line of the road. The selections were approved by the Secretary of the Interior, and the sections were certified by him to the State. Those, however, selected were not from lands lying along the eastern end of the road, as they might have been, but from lands lying further west. Although the Company did a large amount 314*] of grading, as already mentioned, it never completed any part of the road, and in March, 1860, the Legislature of Iowa resumed the lands, interests, rights, powers and privileges conferred upon the Company, and repealed the clauses of the Act granting them. Subsequently, during the same month, it conferred the same lands, rights, powers and privileges upon the Cedar Rapids and Missouri River Railroad Company, another Corporation created under its laws, declaring, however, that the right, title and interest held by the State in the lands, and nothing more, was conferred. This grant by the State was recognized by the Act of Congress of June 2, 1864, amendatory of the original Act of 1856, 13 Stat. at L., 95. By its 4th section it was expressly provided that nothing in the Act should be construed to interfere with or in any manner impair any rights acquired by any railroad company named in the original Act, or the rights of any corporation, person or persons acquired through any such company, nor be construed to impair any vested rights of property, but that such rights should be reserved and confirmed. The new Company afterwards transferred all its interest in the lands to the defendant, the Iowa Railroad Land Company. The question for determination is, whether the plaintiff took a good title to the lands in controversy under the conveyance from the first Company, or whether that title is vested in this last Company. It is contended by the defendants, first, that under the Act of Congress, 11 Stat. at L., 9, no lands could be sold by the State until twenty continuous miles of the road were constructed; second, that if one hundred and twenty sections could be sold in advance of such construction, they could only be taken from lands adjoining the line of the road from its commencement on the east; and third, that the grant by the State to the first Company was upon conditions precedent, which, not having been complied with, the title did not pass. Neither of these positions can, in our judgment, be maintained. The Act of Congress by its express language authorized a sale of one hundred and twenty sections in advance of the construction of any part of the road. It was only as to the sale of the remaining sections that the provision requiring a previous completion of twenty miles applied. It is true it was the sole object of the grant to aid in the construction of the railroad, and for that purpose the sale of the land was only allowed, as the road was completed in divisions, except as to one hundred and twenty sections. The evident intention of Congress in making this exception was to furnish aid for such preliminary work as would be required before the construction of any part of the road. No conditions, therefore, of any kind were imposed upon the State in the disposition of [316 this quantity, Congress relying upon the good faith of the State to see that its proceeds were applied for the purposes contemplated by the Act. Nor was there any restriction upon the State as to the place where the one hundred and twenty sections should be selected along the line of the road, except that they should be included within a continuous length of twenty miles on each side. They might be selected from lands adjoining the eastern end of the road or the western end, or along the central portion. The Act of Congress of May 15, 1856, was a grant to the State in præsenti; it passed a title to the odd sections designated, to be afterwards located. When the line of the road was fixed, and the location of the odd sections thus became certain, the title of the State acquired precision, and at once attached to the land. And the Act of the State, of July 14, 1856, was also a grant in præsenti to the first Railroad Company. That Company took the title and |