
    ALFRED PASQUEAU v. THE UNITED STATES.
    [No. 14765.
    Decided June 8, 1891.]
    
      On the Proofs.
    
    A French officer of engineers brings his invention for movable dams to the attention of the officer in charge of the improvement of navigation on the Ohio. An agreement for the purchase of a license is concluded, hut the Chief of Engineers determines to stop purchasing patent rights, and, while using inventions, leave inventors to their legal remedy without prejudice.
    I.Patent cases against the Government, so far as jurisdiction and damages are involved, fall into six classes, which are stated by the court.
    II.When an inventor proffers his invention, notifies the Government’s officers that it is patented and names his price; and they, being the proper purchasing agents of the Government, adopt the invention and use it, giving an assurance that if the patent prove to he valid and the invention valuable the inventor shall he cómpen-sated, a contract must be implied.
    III. In suoli a case the only questions which arise are the validity of the - patent and the amount of the damages.
    IV. In an implied contract for the sale of a patent right there is an implied warranty that the invention has become property through the instrumentality of a valid patent.
    Y. In estimating damages in such a case the question is, what was the claimant’s device worth in its market at the time it was taken ?
    
      VI. When a device is new and untried and no sales have been made and its value is entirely conjectural, the court will adopt a price agreed upon by the parties in a contract which for other reasons was not executed.
    VII. Where a proposed agreement, in which the parties reached a conclusion as to the value of an invention, is taken as a basis of damages, the court will take into consideration the facts and circumstances which constitute a departure from tbe terms of the agreement, and will increase the damages accordingly.
    
      The Reporters' statement of tbe case.
    The following are the facts of tbe case as found, by the court:
    I. The claimant is a citizen of France, residing at Bordeaux, and engineer in chief of the French Corps de Fonts et Ohaus-sés, and the owner of the invention for an improvement in movable dams, which is appended to and forms a part of these findings.
    II. Ool. William F. Merrill, of the Corps of Engineers, was m 1874 and has been ever since the engineer officer in charge of the improvement of navigation of the Ohio below Pittsburg, exercising, subject to the approval of the Chief of Engineers, all the power and discretion usually confided in and exercised by an officer of engineers in charge of a public work.
    III. In 1874, as the best method of improving the river so as to secure a perpetual depth of 6 feet for navigation, he recommended the construction of a number of movable dams on what is known as the Ohanoine system, one to be located at Davis Island, 5 miles below Pittsburg. The Chief of Engineers, by order dated April 6, 1875, convened a Board of Engineer Officers to consider and report upon the location of this movable dam and a plan for the construction of the same. On the 19th of April, 1875, the board, consisting of Col. H. T. Wright, Maj. Godfrey Weitzel, Maj. O. M. Poe, and Col. Merrill, reported to the Chief of Engineers in favor of the location of the dam at Davis Island at a point a little more than 4 miles below Pittsburg, to consist of a lock 679 feet in length and a navigable pass 400 feet in width, to be constructed on the Ohanoine system, and to be operated by two tripping bars each 200 feet in length. The report was concurred in by the Chief of Engineers and approved by the Secretary of War. But before a dam was constructed the owners of vessels and persons interested in the navigation of the Ohio protested against the erection of a dam with a navigable pass of only 400 feet, and by memorials to Congress represented that such a pass would constitute a dangerous obstruction to navigation, and that no dam should be constructed across the Ohio with a water way between piers of less width than 500 feet.
    IY. In 1880, before a dam across the Ohio had been constructed as previously determined upon, Ool. Merrill pursued his inquiries concerning movable dams in Europe, and learned in correspondence with the claimant that no dam on the Cha-noine system with an opening of more than 213 feet existed in Europe, and that a tripping bar of more than half that length was deemed impracticable or highly objectionable by the French engineers, by reason of the great force required to work it and its liability to be clogged by sand and gravel. He was also informed by the claimant of the improvement effected by his own invention. Ool. Merrill thereupon, August 9,1880, called the attention of the Chief of Engineers to these facts, and requested that a Board of Engineers be convened to consider and report upon such modifications of the movable dam at Davis Island as should be presented by the engineer in charge. Accordingly, the Chief of Engineers, on the 16th of August, 1880, convened a Board, consisting of Maj. W. P. Craighill, Maj. Godfrey Weitzel, and Col. Merrill. On the 9th of February, 1881, the Board reported, among other things, as follows:
    “The present plan for the Davis Island Dam contemplates a navigable pass with a clear opening of 400 feet. The widest navigable pass thus far made in France on the Chanoine system has a clear opening of only 213 feet, although on the Great Kanawha we have two passes with openings of 250 feet and 248 feet respectively. A width of 400 feet is a great advance on 250 feet, and the French engineers express their decided belief that it is impracticable to use tripping bars on passes as wide as 400 feet. We do not agree with them, but inasmuch as the coal-shippers of Pittsburg are unanimous in objecting to even this width as too narrow, andas it would certainly be. extra hazardous, if not impracticable, to increase it while continuing to depend on tripping bars for handling it, it is evidently desirable to find some other system that will enable us to give as wide a pass as may be needed.
    “ In the Pasqueau hurter the prop seat is slightly raised above the floor of the hurter by means of a mass of metal triangular in plan, with a vertical side towards the throat of the hurter. After the prop is in place, all that is needed in order to drop the wicket is to incline it still more upstream, so as to drag the foot of the prop out of its seat and cause it to drop down to the vertical side of the triangular filling piece.
    
      “ If, then we let go of the wicket, the foot of the prop, being without support, slides down the hurter, and the wicket falls.
    “ The adoption of the Pasqueau hurter has been spontaneously recommended by distinguished French and Belgian engineers as the latest improvement. ' A drawing of this hurter will be found in Maj. Merrill’s annual report for 1880.
    “ The advocates of the system urge that the following advantages, among others, are derived firom this change from the ordinary hurter.
    “ 1. Passes can be made as wide as the river if it be so desired, and this has actually been done at La Mulatiere.
    “2. Tripping bars and their, accessories and intermediate piers are no longer Deeded, and their cost can be saved.
    
      “ 3. Bach wicket being absolutely independent of any other, the lowering of the dam can begin at any point and proceed in any desired order. This is not possible with the ordinary hurter.
    “ The Board will remark with reference to the Mulatiere Dam that though the pass has been built, the operation of the system has not been put to the test of actual practical experience.”
    Y. On the 25 March, 1881, the Chief of Engineers authorized Col. Merrill to proceed with the construction of a dam across the Ohio at Davis Island substantially in pursuance of the recommendations of the Board. Col. Merrill proceeded accordingly to construct such a dam, which embodied the invention of the claimant, and which contained a navigable pass of 559 feet in width.
    VI. After Colonel Merrill had become convinced of the utility and necessity of the claimant’s invention in a movable dam with a water way or navigable pass of 500 feet, the following correspondence took place between him and the claimant with reference to the right of the Government to acquire and use the invention:
    
      
      “Mr. Merrill to Mr. A. Pasqueau, engineer of ponts et ehaussées, Lyons, Prance.
    
    “U. S. ENGINEER OEEICE, No. 82 WEST TlIIRD ST.,
    “ Cincinnati, 0., March 18,1880.
    “ My Dear Sir : I received with much pleasure tbe notice of your new system of dams, and the accompanying letter which you did me the honor to send me.
    “I myself have had doubts of the practicability of trippers 400 English feet long, but 1 found that it was absolutely necessary to give our principal navigation, which consists of fleets of coal-barges (not rafts of wood, as you suppose) a pass at least 400 feet wide, which'is the regulation width of navigable passes of bridges, in spite of which dimensions the boatmen complain of its narrowness.
    “An ordinary coal fleet consists of a steamboat, ten barges, each carrying 400 tons of coal, and two small barges carrying sufficient coal for the use of the steamer. I should add that the individuals and companies engaged in the transportation of coal to Cincinnati and points further down the river are much opposed to the introduction of the system of movable dams on the Ohio. This is why I wish to avoid all possibility of getting out of order, and to be certain that the navigable channel will always be open when necessary. Our rises are very sudden, and I have therefore decided to lower the trestles as soon as the wickets of the navigable channel were up, so that if a sudden rise came I could open the navigable pass by means of the tripper, and thus be prepared against all surprises. When 1 was at Lyons, two years ago, I saw your system of hurter, but as I did not wish the bridge of the navigable pass to remain up, I did not see my way to make use of it. One of my assistants suggested, a year ago, that it would be well to use a traveling crane on the upper side of the dam. I was afraid to try it; but since you, who have had much experience, have also designed a crane and have written in favor of its use, I shall resume my studies upon that subject. If it works well I shall avoid the difficulties of the tripper and of the service bridge, and at the same time I shall make a very considerable saving.
    “I shall study up a crane entirely on the up-stream side of the wickets, for I think it would be much easier to-build such a one; its weight will not be so great, and its bracing will be much simpler.
    “In this country no one can use your system of hurter except the officers of the Government. I think inyself that I shall adopt it for the dam near Pittsburgh. In that case I should like to know if your kurter is patented in the United States, and the conditions of using for the dam at Davis Island.
    “If it is not patented in this country I think the best plan would be to wait until your system has been tried, and if the engineers report that it works well then you could demand a gratuity. I think you would have no difficulty in obtaining’ something. The Congress of the United States is liberal enough to inventors whose ideas they use.
    “1 see that we two have worked in about the same manner. I had already made the drawings of a trestle with attached floor like those I saw on the Belgian Meuse.
    “My experience as an officer of engineers, charged with the construction of military bridges, showed me the impossibility of using on our wide rivers any system consisting of many pieces which had to be brought from the storehouse. During the civil war we were obliged to ask the aid of several regiments of the line to transport plank and beams to the bridge.
    * * * * * * *
    “Accept the assurances of my highest regards;
    “ Merrill.”
    “ Mr. Pasqueau to Mr. Merrill, major of Engineers, U. 8. Engineer office, -ZVo. 82 West Third St., Cincinnati, Ohio.
    
    “April 29, 1880.
    “Sir; I hasten to reply to your letter of March 18th last..
    * * * * * * *
    “My patent in the United States was allowed the 10th of February last. It specifies the double-stepped hurrer, the traveling crane, and the other devices which I had patented in France. I think that we can easily agree upon an equitable indemnity, for my system has realized a saving of 55,000 francs at the dam of La Mulatiére, besides the main advantages which it offers.
    “It will be necessary for me to know the principal dimensions and estimates of each of your dams to indicate at what price I will negotiate for each dam.
    “If it suits you I should prefer to relinquish my patent entirely to the Government of the United States, which could then make use of it where it might choose.
    “To make estimates of the cost of your projects, it seems to me that you might put the royalty at $100 a wicket. I would put myself at your disposition to make or to verify all the working dr’awiugs.
    “ Yery truly, yours,
    “Pasqueau.”
    
      
      "Mr. Merrill to Mr. Basquean, engineer of ponte et chaussées, 28 rue Yanbecour, Lyons, France.
    
    “U. S. ENGINEER Office,
    “No. 82 West Third Street,
    “ Cincinnati, Ohio, June 8, 1880.
    “My Dear Sir: I received with pleasure your letter of tbe 29tli of April last, and studied it lojig. I shall reply to it in detail.
    * * * * * * *
    “All changes in the dam at Davis Island have to be subjected to the examination of a board of engineers before being approved by the Chief of Engineers and tlie Secretary of War. I intend to submit a traveling crane, with a manoeuvering boat in reserve, in the event of a difficulty with the crane. JBut it will be necessary to submit at the same time a proposal on your part for the use of your hurter. The proposition you made (.300 francs per wicket) is inadmissible. In the dam at Davis Island, whicli is 1,260 feet long, there will be 315 wickets. At your price we would have to pay you a royalty of 150,500 francs for trying at one single dam a new system which might perhaps not suit us. It is customary in the United States to give the right to try a new patent gratuitously, and if it succeeds, to settle as to the payment afterwards. It so often happens that a new idea does not work well in practice that a practical trial is considered royalty enough for the first application.
    I am certain that the price you name will not be given. It is imimssible. No one would dare to defend the payment of so large a royalty. Americans, as you know, are very ingenious, and perhaps if you ask too much they will endeavor, as frequently happens, to avoid your patent by changes. To prevent that I think it would be better to allow your system to be introduced without making any claim, and if it works well to demand an indemnity. This is the customary method. After a dam has been built it will be time to discuss the purchase of your patent.
    “I ought to tell you that there is a iprejudice against foreign plans, which often annoys me, and that this prejudice will operate against a very large payment to a foreign inventor. I do not share this prejudice myself, but it is a fact which has to be considered, and of which it is my duty to give you warning in good faith.
    “I am much obliged to you for your offer to examine and verity the details of the dam, but it would take too much time, and it is not at all necessary.
    “Pray accept the assurance of my highest regards.
    “Merrill.”
    
      
      " The Resident Engineer of the 2nd district of the special service of the Rhone, to Mr. É. Merrill, major of Engineers, Cincinnati, Ohio.
    
    “Lyons, July 2nd, 1880.
    “Dear Sir: To facilitate the approval of your plans, and the introduction of the dams into the United States, 1 am disposed to greatly reduce the price of the royalty which I indicated in my letter of the 29th of Apfil last. I will also agree that a portion of the royalty shall be paid after the completion of the dam of La Mulatiere, and another portion upon the completion of the Davis Island dam, so that you may be completely assured that my system works in the most satisfactory manner at La Mulatiere, and that it will work equally well at Davis Island if it is well-executed.
    “ But on your part I trust you will recognize possible for me to authorize the employment of my system in the United States without some compensation. I have spent the seven best years of my life in long and laborious researches in order to create this system. I invented and completely designed more than twenty new systems before discovering this arrangement, •which now appears so natural. I made considerable expenditures in experiments, models, travels, patents, etc., and I finished by creating a system which all competent engineers consider the simplest and most practical of all that have been executed for twenty years. It is therefore just that so much labor and expense should receive some reward. You are too equitable to dispute it.
    “ I did not ask a royalty.in France, am of the French Government. Moreover, the French Government has given me for this invention the decoration of the Legion of Hoyior and a promotion, which proves the interest it takes in my system. Moreover, the Government has also had my system carried out under my direction at the dam of La Mulatiere.
    “ There is no reason for my acting thus in the .and in other countries, and I ought to receive a royalty like any other inventor. The Americans are very ingenious; but they have not had, as we, have, the experience of more than thirty years in this particular kind of work. It is much more economical for them, to take first what has been found to be good and then afterwards to try to improve upon it.
    “ We employ in France many America, and we never refuse to pay a large royalty, often very large, which is demanded.
    “ I propose, therefore, to fix the of m.v system to the dam at Davis Island at the fixed sum of 45,000f., one-third of which, or 15,000f., payable upon the approval of the contract which we will sign to that effect, one-third upon the completion of the dam of Mulatiére. and the other third upon the completion of the Davis Island dam.
    “ It is understood that all the designs shall be presented by you, that you may have, as is just, the merit and honor of the remarkable works you are executing, and that I shall put myself entirely at your disposal to give you all the information, designs, and estimates which may be useful to you and facilitate your studies.
    “I expect to send you very soon the designs for a traveling crane (straddling), which I hope will finally convince you that this plan is by far the most practical and the most certain. This, however, is a secondary point, which is not indispensable to the perfect operation of this system.
    “In conclusion I should add that the tripper for the pass at La Mulatiére, which is 103m.60 long, would have cost more than 55,000f., according to a detailed and approved plan. The tripper bars would certainly cost more than 150,000f. if this plan were adopted for the dam at Davis Island, which is nearly 400m long. The laying of these trippers is, in effect, a very tedious and very particular piece of work, which necessitates pumpüfg', of which the expense is enormous.
    “ By my system all these difficulties and expenses are completely avoided. I therefore make only a moderate demand in asking a sum which is hardly a third of the immediate and direct saving which you will make by employing it, besides all the other advantages you will obtain.
    “ Please accept, dear sir, the expression of my highest regards.
    “ Pasqueau.”
    “ilir. Merrill to Mr. Pasqvecm, engineer of fonts et ehaussées, Lyons, France.
    
    “ U. S. Engineer Oeeice,
    “No. 82 West Third St.,
    “ Cincinnati, Ohio, July 23, 1880v
    “ My Dear Sir : I have the honor to acknowledge the receipt of your favor of July 2, which I have read with care.
    “There is only one thing wanting to put us completely in accord. How much do you ask for the absolute sale of your patent % In one of your letters you suggested that the United States ought to buy out your patent entirely. In order to make that arrangement it is very necessary to know the price. Please to inform me of it as soon as possible.
    “There will probably be some difficulty about obtaining permission to purchase your right before the completion of the dam at Davis Island. There are complications and prejudices of which you know nothing; but on the other hand, if your ideas and plans are used and everything goes well, I think you will have no difficulty in obtaining a royalty after the completion of the dam. Moreover, that appears to be much the easiest way, and it is what takes place here every day. If you use some one else’s patent you are obliged to pay on demand. The Government is not under the same laws as private parties, but Congress is liberal enough when there is question of debts of honor.
    “ I write these things to you because it appears to me in all probability I shall be ordered to use your hurter without buying your right, and I wish to tell you that it appears to me to be better for your interests that it should be so. If the patent were mine (and I were not an officer of engineers) I should be content to say nothing until after the hurter had been used. I should be much more certain of obtaining something if the invention had any merit.
    “All that I can do at present is to obtain full particulars information. When I receive your proposal for the sale of your patent I shalbsubmit it to the Chief of Engineers, and at ithe same time express my wish to make use of it.
    “ I thank you for the offer of your plans for a straddling crane, but I have already made plans for such a crane, and also for maneuvering boat to be used in case of accident. That is why I prefer not to see >your crane now.
    “Please accept the assurance of my highest “Merrill.”
    “ The Resident Engineer of the second, district of special service of the Rhone to Mr. Merrill, major of Engineers, Cincinnati (United /States).
    “ Lyons, August 27, 1880.
    “ Dear Sir : In reply to your letter of July 23,1 inform you that I am willing to give up my American patent entirely for the sum of 300,000 francs. This sum divided between twenty dams represents an indemnity of only 15,000 francs a dam, which is very little when compared with the total expense of works of this nature.
    “ You also ask me to allow the application of my system to the Davis Island dam .without saying anything, and after execution you advise me to demand a voluntary indemnity from the American Government. Permit me to submit to you a few iobservations upon this subject. I do not doubt for a single nstaut the perfect equity and liberal disposition of the American Government, but you will understand, I doubt not, that in business matters it is as impossible to depend entirely upon the good will of governments as of simple manufacturers. Now, if after employing my system the American Government should choose to refuse me any indemnity I should be obliged to prosecute it for infringement before the courts. I should be obliged for that to have recourse to lawyers, who ask a great deal in your country, and to expend in costs at least half the sum I should obtain. One of my friends has just done this for a patent he had in England, and half the. amount he received remained in the hands of the intermediaries he had to employ. In this event I should therefore be obliged to ask, not 45,000 francs a dam, but fully 90,000 francs, to be certain of having the net profit I think it just to claim,
    “ It seems to me, therefore, more suitable and more economical for a great nation like yours to have a previous understanding with the inventor, in order to avoid all ulterior dispute.
    countrymen, who are very good business men, have done what I propose to do. Mr. Edison did not wait for an infringement of his ingenious phonograph in France before claiming his right as iuWntor. He sold directly at the price of 500 francs an instrument which cost him 100 francs at most, and by this means he got a royalty of at least 80-100 on the total price.
    “ I have too much confidence in the equity of the higher authorities of the United States engineers to think that they would act otherwise towards me and raise difficulties about allowing me the modest compensation to which I shall be entitled.
    “I thank you again, dear sir, for your kind disposition towards me, and I beg you to accept the expression of my highest regards.
    “ Pasqueau.”
    
      "Mr. Merrill to Mr. A. Pasqueau, engineer of fonts et chaussées, Lyons, France.
    
    “ U. S. Engineer Oeeice, 82 West Third St.,
    “ Cincinnati, Ohio, October 23,1880.
    “My Dear Sir: I received your letter of August 27, a month ago, and I do not know how to reply to you. I presented your plans to the Government and asked permission to try your hurter with straddling crane.
    “a. board was appointed, which up to the present time has done nothing, and on the other hand I hear that the Government does not wish to have anything to do with a patented machine. It is also stated that the dam of La Mulatiére is not yet finished and lacks practical trial. This is exactly the state of affairs at present.
    “ Yon propose to relinquish your rights for the sum of 300,000 francs, founded upon an indemnity of 15,000 francs a dam for 20 dams.
    
      " I do not think it possible to arrange for a payment as large as 300,000 francs, for the right to use a plan which may perhaps be only applied to one single dura, but I think an indemnity of 15,000 francs a dam might possibly be arranged, with the maximum limit of 300,000 francs in all. If you accept this proposal I will do my best for your interests. Please give me an answer as soon as possible.
    * * * * * * *
    
      “ Be pleased, my dear sir, to accept the assurance of my highest regards.
    “ Merrill.”
    
      " The Resident Engineer of the second district of the special service of the Rhone to Mr. 0. Merrill, major of engineers, United States, Cincinnati, Ohio. ,
    
    “ Lyons, Bee. 6,1880.
    " Dear Sir : The figures in the accompanying document No. 1 are extracts from the very detailed plans and estimates made for the dam at La Mulatiére before its construction. If you wish it I will send you complete copies of the official papers from which they are taken. They show that the saving made by the use of my complete system for a pass of 103.00 metres amounts to 122,027.99 francs. Your dams being about 400 metres, and everything much dearer with you, you see that by my system you will save 500,000 francs, or at least 300,000 francs per dam. Moreover, this system is so simple and so practical in its working that there would be every advantage in using it, even if it cost as much as the old Obanoine system.
    “ In the face of so considerable a saving, the board to which your proposals are submitted will certainly see that the royalty asked is very moderate, and ought not to influence their decision. For such great and important works it is, above all, necessary that everything shall be well done.
    “ If you think my system a bad one you ought to reject it, even if I should give it to you for nothing. If it is good and practical it should be recognized that the royalty is an infinitely small consideration and should be entirely neglected in such an important quest on.
    “ You are, moreover, certain that the existence of the patent can not embarrass you, fur it is clearly understood that I give up all my rights absolutely, cither for each successive dam for the sum of 45,000 francs, upon which we have agreed, or finally, for the sum of-300,000 francs, which is now under discussion.
    “ As I have told you, the chief difficulty for me consists in overseeing in your country the uses you will make Of my system, or being obliged to employ agents, if we do not fix the amount of royalty in advance. I am therefore inclined to reduce my demand if I were offered a set price, payable immediately, without my being obliged to employ intermediate representatives.
    “To make my proposals clear, I submit herewith the draft of an agreement in the two cases we are considering.
    “ Mr. Bixby, lieutenant of engineers, now on a mission in France, carné to see the operation of the completed portion of the dam La Mulatiére. He was very well satisfied with the simplicity and certainty of the maneuvers I executed before him. He can bear witness to you of what he has seen and the superiority of this system over the other dams which he visited.
    “Mr. W. Scott, assistant engineer, U. S. Army, on duty on the Kanawha, where it appears there already are two dams, has also been to see that of La Mulatiére.
    “ 1 was absent when he came, and he could not seethe operations of the wickets which are in the river. Nevertheless, he wrote me that this system presented considerable and undeniable advantages over all that he knew.
    “ There is, therefore, every reason to hope that your proposals will be favorably received by the board charged with approving them.
    “ Please accept, dear sir, the expression of my best regards.
    “PAsqueau.”
    “ Mr. Merrill to Mr. A. Pasqueau, engineer ofponts et ehaussées, Lyons, France.
    
    “ U. S. Engineer Office, No. 82 West Third St.,
    
      Cincinnati, 0., January 19,1891.
    “Mi Dear Sir: I have just made a visit to Washington, and had a long talk with General Wright, Chief of Engineers of the Army, as to the Pasqueau system for the dam at Davis Island, and your proposals to relinquish all your rights to the United States in consideration of'thesuin of 200,000 francs, payable within one year, or 15,000 francs a dam.
    “ I have discovered a serious obstacle which I had not foreseen. In the United States, as in France, all patents for inventions are granted without any guarantee by the Government. The consequence is that the validity of a patent can be finally established only by legal proceedings in the courts. The Government is not competent to decide as to the validity of a patent, and it lias often happened that it has made yearly payments on a patent for several years, and finally discovered that the inventor had no rights, and has been obliged to make repayments ti) some one else. Moreover, accusations of favoritism have been brought, and given rise to scandals.
    “Finally, the Government decided, some time ago, to pay no one without a decision by the courts. Cases arise most frequently in the Ordnance Department, and I myself consulted the Chief of Ordnance, under orders from the Chief of Engineers. He assured me that in his department patents are never paid for except upon judicial decision, and he advised the adoption of the same plan. The Chief of Engineers took his advice, and absolutely refused to make any arrangement for the purchase of your patent. They do not refuse to pay for the invention, for they have no intention of stealing the ideas of others, but experience has shown them that the method adopted is the only one which jirotects the interests of all parties.
    “You wrote me that one of your friends was obliged to prosecute the British Government. Is it not possible that the same obstacles exist there as are found here?
    “lam very sorry to have to write you thus after such a long correspondence, but the decision of the Government surprised me as much as it will no doubt surprise you! I found your draft of agreement very reasonable, and I had many hopes of securing its acceptance,
    “ But it is necessary to face the situation, and take the best course which is left to us.
    “ If we do not adopt the Pasqueau system for the dam at Davis Island, you will assuredly derive nothing from your patent in the United States.
    “ If, on the contrary, we do adopt it, it will cost you nothing, and will give you a cause of action against the Government, out of which you may make some money in the future.
    “ It therefore appears to me the best thing I can do, as a friend and as an engineer, is to urge the adoption of your system.
    “ T am very sorry that our arrangements have fallen through, but I have done what I could for your interests as if they were my own.
    “Please accept, my dear sir, the assurance of my most devoted regards.
    “ MERRILL.”
    “ Mr. Merrill to Mr. Pasqueau, engineer of ponts et ehaussées, Lyons, Prance.
    
    “U. S. Engineer’s Office, No. 82 West Third St.,
    “ Cincinnati, 0., March 26, 1881.
    “My Dear Sir: I have just returned from Washington, where I saw the Chief of Engineers. He has finally decided to try the Pasqueau hurter at the Davis Island Dam, and he has authorized me to notify you, so that you may claim all the rights which you possess.
    “ As to your relations with the factory which wishes to purchase your patents for the United States, I think the Government has nothing to say.
    “Yon have without doubt the right to sell your patent to whomsoever you may choose.
    
      “ Accept, my dear sir, tlie assurance of my most sincere regards.
    “ Merrill.”
    “ The Engineer-in Chief of Fonts et Chasusées to Mr. Merrill, major of Engineers, U. S. A., 82 West Third st., Cincinnati, 0.
    
    
      “ Bordeaux, July 10,1881.
    “Dear Sir: I have just been appointed to the higher rank of engineer-in-chief at Bordeaux, and the inconveniences necessitated by this change of residence have prevented an earlier reply to your last letter. Now I am established in my new position and will be able to take up again the course of your correspondence.
    “ I saw by your letter, v¿th the greatest pleasure, that United States Government had definitely adopted your plans and my system of movable wickets. I am taking steps to secure my rights through a lawyer, or to assign them to an iron manufacturer.
    “ However, I am very sorry that the Government has not accepted your proposition to treat with me in person, and compels us to resort to the courts, which will be tedious and costly for yourself as well as for me.
    “ In such case we make in France what we call an “agreed judgment.” When there is an agreement, as between ourselves, upon the basis of the matter, and when it is desired to give the effect of a judgment to that agreement, both parties direct their attorneys (solicitors) to prepare a judgment, which each accept s. They then request the court to render a decree in conformity therewith.
    “ This decree, which, is rendered without pleadings and with much less expense, has as much force as any other.
    “ If the United States law admits this method, we would be able to have an agreed judgment according to the terms indicated in my draft of agreement; otherwise, I shall be obliged to cause my lawyers to demand a much greater royalty, as I have already told you, to cover the large expense which this will cause me.
    “ The La Mulatiére Dam, whose construction I continue to supervise, will be entirely finished in the course of the coming month. The steam winch works perfectly; the wickets are operated with remarkable rapidity and precision.
    “The weir is all completed; the rolling bridge has been placed in the abutment; they write me that it works in a very satisfactory manner. I believe that we will have the whole dam operated during the low water of this year, which occurs in October.
    “ Very truly, yours,
    “ PASQUEAU,
    “ 59 Hue Lafaurie de Monhadon, Bordeaux, Gironde.”
    
    
      “-Mir. Merrill to Mr. Pasqueau, engineer-in-chief of fonts et chaussces, Bordeaux, France.
    
    “U. S. Engineer Oeeice, No. 82 West Third St.,
    
      Cincinnati, 0., September 5, 1881.
    “Ml Dear Sib: Please accept my very sincere congratulations on the occasion of your promotion to the grade of engineer-in chief.
    “It is a well-deserved promotion.
    “Your letter was sent to the Chief of Engineers, but he has not yet made a reply. When he arrives in Washington after his vacation I think he will do something.
    “ We must wait until then.
    “Please accept, my dear sir, the assurance of my highest regards.
    “ Merrill.”
    VIL The proposed agreement referred to in the preceding letters of December 5, 1880, and January 19, 1881, is in the following words:
    
      “Draft of Agreement.
    
    “ Between the undersigned, W. E. Merrill, major of Engineers, United States Army, acting in the name of the Government of the United States of America, subject to the approval of the proper authorities, and A. Pasqueau, engineer of the corps of pouts et chausses of France, acting in his own name and on his personal accouut, it is agreed as follows:
    “Art. 1. Mr. A. Pasqueau, holder of the patent granted by the United States on the date of-,-, under the No.-, with amendments, for the invention of a new system of movable dam, declares that he relinquishes to the United States the full and entire title to his patent and its annexes on the following conditions:
    “Art. 2. The Government of the United States shall pay to Mr. Pasqueau the sum of fifteen thousand francs (15,000) six months after the approval of the present agreement, and thirty thousand francs (30,000) after the construction of each of the dams to which this system shall be applied in the United States.
    “The total amount of the sums paid shall not exceed 300,000 francs, no matter what the number of dams constructed, and when it has reached this figure the United States shall become the sole and final proprietor of the patent and its annexes.
    “Art. 3. In consideration of the payment of the above-mentioned sums, Mr. Pasqueau agrees to furnish all the information and advice for which he shall be asked to insure the perfect success of the dams constructed upon the system.
    
      “He furthermore enimages n-t to take out in the United States any other patent or amendment for any improvement which he may afterwards make in this same system.
    “Made in duplicate at-the-, 188 — .
    “Note. — In the event of the Government of the United States preferring- to purchase the patent directly, Article 3 may be replaced by the following:
    “Art. 3. The Government of the United States shall pay to Mr. Pasqneau the sum of two hundred thousand francs (200,000) within one year from the date of the signature of the present agreement.
    “ Immediately upon the payment of the sum it shall become the sole proprietor of the patent and its annexes.”
    VIII. The Government subsequently,by its engineer officers, with the approval of the Chief of Engineers, applied the claimant’s invention of two movable dams on the Great Kanawha, as hereinafter more particularly shown. The invention is still in use in all of the said dams, has proved to be valuable, and has fulfilled the expectations in regard to its efficiency that were entertained of it by Colonel Merrill and the other engineer officers.
    IX. The dam across the Ohio contains a navigable pass of 559 feet; was completed October 8,1883, upon the system or invention of the claimant, and contains 332 of his patented hurters in actual operation.
    Dam No. 5, on the Great Kanawha, as constructed, contains a navigable pass of 250 feet and -was completed in the spririg of 1884, and employs 72 of the claimant’s patented hurters in actual operation.
    Dam No. 6, on the Great Kanawha, with a navigable pass of 284 feet, was completed about the first of Januarv, 1886, shortly before the bringing of this action, and contains 139 of the claimant’s patented hurters.
    X. The cost of construction of a movable dam operated by the claimant’s device is less than that of one operated by the old or Chanoine system, and the saving effected in the cost of construction by the use of the claimant’s invention in the three dams before described was upwards of $25,000. A dam with the claimant’s device is also operated with fewer men than a dam built after the Chanoine system, and the saving effected in the operating the three dams before described during the life of the claimant’s patent would amount to upwards of $7,000. It does not appear that at the time when the invention was appropriated by the Government it had any market value, or that it now has either in Europe or in this country, nor does it appear that any sale of the invention has ever been made, it oeing a device useful and applicable only to navigable streams, and one which private persons would rarely need. It was regarded as of great value by the French Government, and the proprietary right of the claimant was recognized, but he being an officer in the French service, and the invention being used in a department under his own supervision, he accorded a gratuitous use of it to his own Government. A number of accomplished and experienced civil and mechanical engineers, skilled in the science and art of hydraulic engineering, who have made a special study of the subject of movable dams, as well as of the claimant’s invention, and of the value of the same, in connection with the movable dams constructed by the Government on the Ohio and Great Kanawha, have testified to what they deemed a reasonable royalty for its use. Their estimates range froth $5 to $100 per hurter, the average being about $57 per hurter. But their estimates were not founded upon the knowledge of actual sales of this device, but rested upon the analogy of prices paid for other and different inventions. The court, regarding the agreement tendered by the claimant and set forth in finding vn, and the acceptance of the terms therein proffered by Colonel Merrill, the proper purchasing agent of the Government, set forth in his letter of January, 19, 1881, before quoted in finding vi, as furnishing better and more satisfactory evidence of the amount of the royalty which the claimant should recover, finds that the value of the invention at the times, respectively, when it was applied and used by the Government, including the right to use the same during the existence of the patent, was in the aggregate the sum of $26,000.
    The following are the patent and specifications referred to in the foregoing findings:
    “ No. 225,533.
    “THE UNITED STATES OE AMERICA.
    “To all to whom these presents shall come:
    “ Whereas Alfred Pasqueau, of Lyons, France, has presented to the Commissioner of Patents a petition praying for the grant of letters patent for an alleged new and useful improvement in clongh-dams or sluice-weirs, a description of which invention is contained in the specification, of which a copy is hereunto annexed and made a part hereof and has complied with the various requirements of law in such case made and provided
    “ And whereas upon the examination made the said claimant is adjudged to be justly entitled to a patent under the law:
    Now, therefore, these letters patent are to grant unto the said Alfred Pasqueau, his heirs or assigns, for the term of seventeen years from the 16th day of March, one thousand eight hundred and eighty, the exclusive right to make, use, and vend the said invention throughout the United States and the Territories thereof.
    “In testimony whereof I have hereunto set my hand and caused the seal of the Patent Office to be affixed at the city of Washington, this sixteenth day of March, in the year of our Lord one thousand eight hundred and eighty, and of the Independence of the United States of America the one hundred and fourth.'
    [seal.] “ A. Bell,
    
      “Acting Secretary of the Interior,
    
    
      “ Countersigned.
    “H. E. Paine,
    “ Commissioner of Patents.”
    [Plate omitted.]
    “[Specification forming part of letters patent No. 225,533. Application filed January 19, I860.]
    “To all whom it may concern :
    “ Be it known that I, Alfred Pasqueau, of the city of Lyons, in the department of the Rhone and Republic of France, have invented a certain new and useful improvement in dough dams or sluice-weirs; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification, and in which—
    “ Figure 1 is a sectional side elevation illustrating the application of my invention. Fig. 2 is a top or plan view of the sliding shutter-brace abutment; and Fig. 3 is a longitudinal vertical section of the same through line x x in Fig. 2.
    “Similar letters of reference indicate corresponding parts in all the figures.
    “ My invention has relation to movable dough dams or sluices Used in rivers or channels for the purpose of causing overflow by damming up the water* or for the purpose of increasing the depth of water in the river or channel at any given point or points.
    “ As heretofore constructed this class of dams consists of a series of detached shutters placed in a line with each other transversely across the channel or river, and hinged at their lower ends to sills or piers which are imbedded into or built up from the channel or river-bed, and which are therefore liable to obstruct navigation and impede the flow of the current when the dam is down.
    “ My improvement consists in the construction and arrangement of a channeled abutment provided with a series of steps or shoulders forming inclined planes leading from one to the other, and which operates in combination with detachable shutters hinged by their middle to supports or braces, the lower free ends of which are adjustable in the channels or grooves of the abutment, and impinge upon its steps or shoulders, substantially as hereinafter more fully described.
    “In the annexed drawings A, Fig. 1, represents the riverbed or bottom, and C O' the sectional dam or shutters, one of which is shewn up and the other down. The number of these shutters, which are all of equal width and height, will, of course, depend upon the width of the water-course which is to be dammed up. Bach of the shutters 0 is hinged by its middle to a brace, D D', and is provided with a supplemental support or double brace, B E', the lower end of which is hinged in bearings e, embedded in the river bottom.
    “ It will be observed that both ends of the shutters 0 O' are free, and that their lower ends, in raising them into a vertical or approximately vertical position, will abut against a shallow step or sill B, in the river-bed. A suitable distance in front of this sill I place my abutment, which is denoted by the letter F, and is held firmly in the river-bed by its downward-projecting dovetailed transverse flanges /f, which may, however, sometimes be dispensed with where the river-bed is of a nature to admit it. This abutment, as will be seen more clearly by reference to Figs. 2 and 3 of the drawings, consists of a series of inclined planes, abo, forming a series of steps or shoulders (denoted by a' b‘ o'), the part of section a sloping off laterally oi1 sidewise past the next sections b and o, and divided from the latter by a ridge or flange i, leading into the groove or channel (V, while the inclined planes b c, in regular succession, open up into the parallel groove or channel d.
    
    “ Reference being now had to Fig. 1 of the drawings, operation of my invention will readily be understood. The shutters to be raised into position to form the dam are stepped against the sill B by means of the breech- chains g h, which are operated by means of a windlass, H, placed on top of the derrick Q-. It is obvious that instead of this derrick a traveling crane (operating one or more shutters at a time) may be used, or a floating derrick may be employed, if desired. Other chains are suitably arranged and operated by the windlass for the purpose of bringing the top end of the shutters into proper position; but these chains are relieved from all strain by means of the braces EDE' 1)', and the inclination of the shutters (by which the depth of water is, of course, regulated) is adjusted by means of the braces D D' and stepped abutment F. If it is desired to lower the shutter into the position shown at O', it is first raised until its brace D' slips, with its lower end, out over the inclined plane b into the chanuels or grooves a" d', within which it will gradually assume a horizontal position, being guided into the converging, channel or groove d, when it is again in a position to be raised through the inclined planes c 5, with their stops or abutments, which regulate the pitch or inclination of the shutter.
    “It will thus be seen that no chains or other operating devices are necessary at the braces D D', which are operated automatically by the shutters and the stepped and channeled abutment F, in the manner described.
    “Having thus described my invention, I claim and desire to secure by letters patent of the U nited States—
    “ 1. The abutment F, provided with aseries of inclined planes abo, having steps or shoulders a1 b' o', and grooves or ways a" d! d, substantially as and for the purpose herein shown and specified.
    “2. The combination, with the adjustable shutters of a movable dough or dam and their braces, of the automatically-operating brace abutment F, provided with a series of inclined planes, abo, having steps or shoulders a1 V o’, and grooves or ways a" d'd, constructed and operating substantially in the manner and for the purpose herein shown and set forth.
    “ In testimony whereof I have hereto affixed my signature in the presence of two subscribing witnesses.
    “Alebed Pasqueau. '
    “ Witnesses:
    “M. ClVVING-,
    “G. Klein.”
    
      Mr. J. Hubley Ashton and Mr. Anthony Pollolt for t he claimant:
    The army officers, who proposed that Mr. Pasqueau should be offered $5 a hurter for this invention, at the same time recommended in their report that the attention of the Commissioner of Patents be called to this case, “ with a suggestion that he recommend to Congress to make such amendment to the patent laws as will hereafter allow free use to the United States of any patent granted under its authority; ” a provision which the Supreme Court of the United States declared Congress has no power to enact, and which, if attempted to be enacted, would be absolutely unconstitutional and void.
    The question left open in James v. Oamplell as to the jurisdiction of this court over claims by patentees for compensation for the use of their inventions, without their consent, by public officers, acting’ on behalf of the Government, under the sanction of legislative enactments by Congress, was expressly adjudged in Hollister v. Benedict Man/. Go. (113 U. S. B.. 67).
    In the case of the Great Falls Manufacturing Co., the court adjudged that the appropriation of money for the construction of the dam, there involved, was equivalent to an express direction by the legislative aud executive branches of the Government to its officers to take the property necessary for that purpose, and that the claimant had a right, electing to regard the action of the Government as a taking under its sovereign right of eminent domain, to demand just compensation. Great Falls Manufacturing Go. (112 ü. S. B., 645).
    There can be no doubt that, upon the doctrines of these authorities, the adoption of this invention by the Engineer Department, for use in the public works of the G®vernmeat, and its use therein by the officers charged with the construction of those works, acting under legislative authority, imposed a legal obligation upon the United States to make just compensation for the use of the invention, which is enforceable by the present action in this court.
    The right of the patentee, and the duty of the United States to compensate him, were acknowledged when the invention was adopted and appropriated for the dams; and the acts of Congress, which authorized and provided for them, were, in contemplation of law, an express direction by the legislative and executive departments of the Government to its officers to take and use the invention for the purposes of the construction and operation of those public works.
    Many inventions relating to subjects which can only be used by the Government are not intended to, aud do not in fact, introduce or effect any economy in the public service, their whole merit consisting in the new anti important results never attained before in the art, which they enable the Government to accomplish by their adoption and use in the public service; and in such cases to hold that such beneficial results are not legitimate subjects for consideration in determining.the value of the inventions, when taken for public use, would be to enable the United States to appropriate them without making any substantial return to those whose genius produced them, which would be a practical denial of their constitutional right to compensation.
    The notion that the value of a great invention, used in the public service, is to be measured simply by the economy introduced by it, was distinctly repudiated by this court in the Dahl-gren case, where the court found that some of the advantages gained by the United States by the use of the invention could be weighed and measured, while others could not be measured by a money standard, but the court nevertheless gave them all effect, and properly so, in fixing the compensation awarded the claimant for the use of the invention, and by the rule laid down in Suffolk Go. v. Hayden (3 Wall., 320), found the measure of the claimant’s compensation in “the utility and advantages of the invention to the United States over the old modes or devices that had been used for working out similar results.”
    These principles conform to the rule laid down by the Supreme Court for estimating the compensation for real property taken for public purposes in the case of the Boom, Go. v. Patterson (98 U. S. It., 403), which was applied by this court in the case of The Great Falls Manufacturing Go. (16 C. Cls. K., 198), affirmed, on appeal, by the Supreme Court. The Supreme Court there held that the compensation was to be estimated by reference to the most advantageous and valuable uses to which the property was adapted or might be applied.
    In equity, under the rule in Mowrey v. Whitney (14 Wall., 620), the fruits of the advantage gained by the infringer over what he had in using the old process or devices, constitute the recoverable “ profits.” At law, where the jury must resort to general evidence, the rule in Suffolk, Go. v. Hayden (3 Wall., 321), is that the utility and advantages of the invention over its predecessors are the measure of the plaintiff’s “ damages.”
    The infringer is bound not only to account for all his.profits, but to pay the patentee “damages” as well.
    The character, utility, and value of the invention here involved are undisputed and indisputable, it may be said to represent the furthest advance yet made in the art to which it pertains. The problem presented to Mr. Pasqueau in designing tbe La Mulatiére Dam, which required a pass of 340 feet (127 feet wider than that at Melun, the widest pass then in Europe) was the discovery of some means of doing away with the old-fashioned tripping-bars, and enabling an engineer to give to the navigable pass of a movable dam a free and unobstructed opening of any desired width.
    This he accomplished by a device so simple that it causes one to wonder, on seeing it for the first time (as was said of the telephone), that it had not been invented long before. “ This is often the case,” as the Supreme Court has observed, “ with inventions of the greatest merit.” (Loom Co. v. Higgins, 105 U. S. JK., 501.)
    The increased width which the Government was able to give to the pass, by means of the invention, represents all the enormous difference between the value of a dam, with such a navigable pass as the public interests and the public policy demanded, and the value of a dain w’hich, had it been built, would have been little better than a legalized nuisance.
    That this difference in value is vastly more than the whole amount of the present claim can not be gainsaid.
    That the amount of this claim would have been a trifling sum for the Government to pay for the means which would enable it secure such a dam, which was to cost nearly a million dollars, is a thing too plain for argument.
    Certainly, an invention which rendered it practicable for the Government to make the pass of this work of its present width is worth vastly more than a railroad or bridge company, constructing a bridge across the Ohio, would have been forced to expend to obtain the increased channel span required by the act of 1883.
    It has been assumed above, arguments gratia, that a 400-foot pass could have been successfully maneuvered with the old tripping bars; but if the fact be as we apprehend it is, that those bars would not have worked at all, or would have been extremely difficult, hazardous, and costly to operate on such a pass, the Unite*! States gained, specifically, in the second place, in addition to the benefit of a pass of adequate width in this dam, at least, all the advantages involved in and derivable from a perfect and satisfactory system for operating that pass, as eompa> ed with a system for operating a pass of inadequate width, which, if it would have worked there at all, would have been attended with immense risks, dangers, and expense, as well to the United States as to the commercial interests concerned in the navigation of the Ohio.
    Certainly, it can be plainly seen that the worth of such advantages, also, is far greater than the whole amount of this claim, and, if the United States had not saved a dollar in construction or otherwise, by the use of the invention, the advantages arising from the ability to operate the navigable pass in a proper manner alone, would be cheaply bought at the price of many thousands of dollars more than are asked in the present case.
    If, however, as is probable, according to the opinion of the French engineers, the pass originally proposed could not have been operated at all by the old tripping bars, the comparison to be instituted is between a living and working machine, adequate for the purpose intended by Congress, and a machine which is no machine, and not only worthless for any purpose whatever, but a positive injury and evil to all concerned.
    As we have said, had the tripping-bar system, in the dam as at first proposed, broken down, the trouble could not have been remedied simply by taking out the tripping bars and substituting the Pasqueau system of operation; the G-overnment would have been obliged either to reform the dam, and make the pass at least 500 feet wide, in order to satisfy the requirements of the navigation and its public policy in regard to the river, or to destroy the whole structure as an actual nuisance, at the threshold of Pittsburg, in the great highway of the Ohio.
    The latter alternative would have involved a direct loss to the United States of the vast sum expended by it in constructing the work.
    The invention was adopted by the United States in express view of its capacity to accomplish the results which have been obtained by its use, and for the solé purpose of enabling the Government to secure by its use the benefits and advantages referred to. It was taken, therefore, by the United States in direct contemplation of those benefits and advantages, which are thus necessary and proper elements of the compensation which the United States is bound to pay for the use of the property.
    
      
      Mr. W. J. Rannells (with whom was Mr. Assistant Attorney-General Ootton), for the defendants:
    1. Pasqueau had by publication voluntarily given to the world this invention to be used by his brothers in the profession at will. If so, theu there was a voluntary abandonment of this invention, and he can not after that repossess himself of any personal or exclusive right in it by afterwards securing letters-patent for the same. It will be seen, and is conceded, that on October 3, 1878, more than four years subsequent to this publication, he filed his application for letters patent in the French department of commerce and agriculture, and which application was allowed and a patent issued January, 1879. Bell v. Daniels (1 Bond 219).
    The same rule is made in Melius v. Sillsbee (4 Mason, 108); in Egbert v. Lipman (104 U. S., 337); Pitts v. Mall (2 Blatch., 229); McCormick v. Seymour (2 Blatch., 240).
    It may be pertinently observed here, what act could more conclusively show the intention of the inventor to devote his improvement to the public in general than that of Pasqueau’s publishing to the world his improvement? No stronger evidence of his intention to dedicate to the public could be expressed by any other act. But his intention is all the more manifest when it is coupled with the delay of making application for patent almost five years thereafter.
    The American Law Times, of September, 18C9 (2 A. L. T., 129), has the following under head of digest of important rulings in patent cases (on appeal from the Commissioner of Patents):
    “An invention which is allowed to lie dormant for a period of five years must be held to be abandoned. (Fisher, J., in Carleton and, Merrell v. Atwood.) ”
    Much more should abandonment be held when this length of time has gone along with a printed publication of the device.
    But the evidence shows that or about the time of the claimant’s application for his French patent he had surrendered to the Republic of France the free and gratuitous use of the Pasqueau invention. The agreed statement of facts says:
    
      “The said French patent was designed to secure to the French Government the free and gratuitous use of his said invention wherever it might think it advantageous to employ it.
    This admission is broad enough to permit France to use the invention in every other country if it found it “advantageous to employ it.” If this was the length and breadth of Pasqueau’s donation of the use to France, then it is respectfully urged that that kind of a donation amounts to a complete dedication to the public in general.
    The defendant therefore insists that for the purpose of determining the question of abandonment, that the acts of Pas-queau should be grouped together, and that their inevitable logic is that Pasqueau freely and of his own accord abandoned or dedicated his invention to public use long before his application for his American patent, and that therefore it is a void patent, and he has no right to recover.
    2. The court (which is the jury here) does not have the power to triple daihages, as in an ordinary case of tort; it must be controlled solely upon the question of compensation by what the proofs actually show the claimant is entitled. In Blalce v. Robinson (94 U. S. R., 728), the court say damages must be proved, and will not be presumed. In Retirle v. Imhauser (14 Blatcli., 19), the court say no consequential damages are given, they must be shown to have been actually sustained. In Gold v. Ives (119), the court say the jury will not be allowed to conjecture damages, they must be proved.
    
      Gould Manufacturing Co.v. Goiving (14 Blatch., 315), evidence of actual damages is necessary to recover.
    In Schwarzel v. Hollenshalls (2 Bond, 29), the court say: “ Where plaintiff fails to establish a right before the jury to more, than small damages it is his fault or misfortune that they can not find more than the actual damages proved.”
    The rule in 21cKeever,s Case (14 C. Cls. R., 430),' which permits the court to consider the testimony of expert witnesses for the purpose of measuring damages or compensation in connection with the Dahlgren Case (1G C. Cls. R., 30), Suffollc Go. Case (3 Wall.', p. 15), is the one counsel presumes the court will apply here. In considering the compensation due claim"ant, the court will no doubt keep in view the very pertinent fact that the use by the defendant of claimant’s device created all the value it possessed; there was no other person in this country to use it. But for this use the claimant’s device would have been known in this country only in the Patent Office and scientific periodicals devoted to the discussion of hydraulic engineering.
    Claimant’s counsel cite the Dahlgren case (16 C. Ols. B., 30). But that case is peculiar to itself. It was sent by Congress to that court by a special act, hemmed in by rules and directions, and the court could not have carried out the intention of Congress by following any other rule than the one adopted by it in fixing the amount of compensation. Aside from this, the proofs in that case showed, and the court found, the improvements in marine ordnance derived from Admiral Dahlgren’s patents had advantages capable of mathematical demonstration, equal to, or more than the amount of the maximum judg-rnent authorized by that act, viz: A larger shell to the same amount of metal, (2) its greater safety, (3) its greater power, (4) its economy of powder, and (5) its requirement of a smaller number of men to the same amount of metal. (16 C. Cls. B., 53.)
   Nott, J.,

delivered the opinion of the court:

This case has involved on both sides an immense amount of labor and expense. The evidence has been of the most costly kind, the testimony of experts, and the arguments of the most exhaustive character. The subject-matter of the suit is a patented invention, and the suit has been tried as if it were an action for infringement involving the validity of the patent. The state of the art, the history of the invention, the magnitude of the field of operations, the utility of the device, the saving which will accrue to the defendants, the benefits which have enured or may enure from the use of the invention, even the length, breadth, and commerce of the rivers upon which it has been applied have been the subject of proof and argument.

So far as jurisdiction and damages are involved, the patent-litigation of the Government has developed several classes of cases. First, where the right to use an invention has been acquired by express contract, in which it was early determined that a patent right is property and that the Government has no reserved right to use an invention without compensation (Burns’s Case, 4 C. Cls. R., 113; 12 Wall., 256). Second, cases where in the absence of an express contract the inventor has proffered his device to the proper officers of the Government, and they, with knowledge or notice that it was protected by letters patent, have adopted and used it without procuring a license or agreeing upon the amount of the royalty (McKeever’s Case, 14 C. Cls. R., 396; affirmed 18 id., 757; Palmer’s Case, 128 U. S. R., 262). Third, where the officers of the Government have used an inventor’s device knowing it to be his, but not knowing it to be patented and not supposing that he would seek a royalty (Solomon’s Case, 22 C. Cls. R., 335; Gill’s Case, 25 id., 415). Fourth, where the ordnance officers, in pursuance of the policy of that department, have adopted a device without inquiring as to the right of property in the inventor, but with the intention that if he can substantiate such a right he shall be paid a royalty (Berdan’s Case, ante, p. 48). Fifth, where there has been an unintended use of an invention through the ignorance, carelessness, or mistake of a public officer (Forehand’s Case, 23 id., 477). Sixth, where the officers of the Government at the time of the construction of a public work have expressly disclaimed an intent to use an alleged device, or have denied the validity of a patent or that the work under their charge involves an infringement (Schillinger’s Case, 24 id., 278).

The present case unquestionably belongs to the second class. The inventor proffered his invention to the defendant’s officers; he notified them that it was patented; he named the price at which he would grant licenses or dispose of the entire right. The officers were the proper purchasing agents of the Government, charged with the construction of a public work in which the inventio.il was used; they first learned of the existence of the invention from the inventor; they examined it and adopted it and entered into negotiations for it, and virtually agreed upon the pri.ce to be paid; and, finally, after refusing to enter into an express contract, gave the assurance that if the patent proved to be valid and the invention valuable the inventor should be fairly and justly compensated for its use.

In such a case only two questions can arise — the validity of-the patent and the amount of the damages.' In a sale of personal property one warranty is always implied — that it is the property of the vendor. So in these implied contracts for the sale of patent rights it must be implied that the patentee owned the property, i. e., that tbe invention has been rendered property through the instrumentality oí a valid patent. In the present ease there is no question of novelty or originality or infringement, and consequently the only question is that of damages; what was the property really worth, what is a reasonable royalty to be recovered by the claimant?

In almost every patent case that has come before this court the claimant has sought to establish his damages by the same ■proofs, arguments, and deductions that are usual and proper in actions for infringement; and in almost every case for the use and occupation of real property the claimant has endeavored to recover asñf he were entitled to damages in trespass. In these two classes of cases it is a common thing for the claimant to allege and prove that the defendants used his invention or intruded upon his premises without his license or consent. In actions for the taking of personal property no such misapprehension has occurred, probably because every one has been familiar with the doctrine of the common law that the owner may waive the tort and sue on an implied contract for the proceeds of his goods. The evidence offered has been invariably to show the taking and the value; and the damages sought have been what the property was actually worth. Yet there is no distinction in principle between these different classes of cases, and in this court there has never been a distinction in practice. Since the leading case of Johnson (2 C. Cls. R., 391) it has been uniformly held that the entry of the Government upon real property is never tortious* and that the recovery must be that of an implied rent, such as the owner would have asked and the tenant would have given if the transaction had taken the form of an express contract (Page’s Case, ante). And in ¡latent cases since the leading case of McKeever (14 C. Cls. R., 396; affirmed 18 id., 757) it has likewise been uniformly held that the damages are to be reduced to a reasonable royalty.

In the present case there has been an immense expenditure of time and money to establish on the one side that the Government acquired vast commercial advantages and saved large sums of money and escaped irretrievable losses by virtue of the claimant’s professional advice and the use of his patented invention ; and on the other side that the Government saved little or nothing; that the judgment of its engineers in selecting the claimant’s device was in some instances erroneous, and that a Cheaper device than either the claimant’s or the Cha-ncine, the needle dam, might have befen used, which in all likelihood would have answered just as well. If the Government had taken a man’s horses to draw a train of military supplies it would not be admissible for the owner to measure his damages by showing that the services of the horses were of incalculable value to the Government, saving the stores or relieving the wants of troops in the field. Conversely it would not be admissible for the defendants to show that the quartermaster who impressed the horses erred in judgment; that there was no need of haste; that ox trains would have carried the stores with sufficient speed, and therefore that the owner’s recovery should be limited to the benefit which the Government actually derived from the use of his property, viz, to the value of so many oxen instead of so many horses. On the contrary, no one would have doubted that, the fact to be proved and the question to be answered would be, what was the value of those horses in the local market at the time they were taken?

We come now to the actual question of damages. What was the claimant’s device worth in its market at the time it was taken ? As in many of the other patent cases which have been before the court, the invention at the time of the taking had no market value; it was one likely to be used only by governments on navigable streams, and that rarely. Moreover, it had not then been actually tested in its own limited field. The question is not what experience has shown the invention to be worth, but what it was worth when the Government appropriated it? That question, generally a difficult one in such cases, is here greatly simplified by the acts of the parties.

It appears that Colonel Merrill was the managing and purchasing agent of the Government, and that subject to the approval of his superior officer, the Chief of Engineers, he had as much discretionary power to purchase a license under this patent as to purchase the plank and stone and iron in which it would ultimately be reduced to material form and used in the service of the Government. It likewise appears that the purchase of this right for the Government was a subject of negotiation between Colonel Merrill and the inventor; that the latter at first asked $100 a hurter; that Colonel Merrill flatly refused to give that price; that the negotiation went on by letter, until finally the inventor reduced his price to 15,000 francs to be paid within six months and 30.000 francs payable whenever a dam should be completed. This offer, moreover, was not only in writing, but actually reduced to the satisfactory form of a written agreement, though the written instrument was not executed, and in that specific form Colonel Merrill virtually accepted the offer and agreed to the terms of the proposed contract, subject to the approval of the Chief of Engineers. We say “virtually,” for the acceptance did not take that precise form, yet it was that in substance. If the Chief of Engineers had approved the recommendation of Colonel Merrill an effective and satisfactory express contract would have been entered into by the inventor on the one side and the Government of the United States on the other. Colonel Merrill explicitly, and we think very properly, said in his reply to the proposition:

“ The decision of the Government surprised me as much as it will no doubt surprise you. I found your draft of agreement very reasonable, and I had many hopes of securing its acceptance.”

He had also come immediately to Washington after receiving the proposed agreement to explain to the Chief of Engineers the desirability of the purchase, and he had been, as he says, greatly surprised and disappointed when he found that the Engineer’s Office had determined to adopt the policy of the Ordnance Department, which is to take advantage of all knowledge and of all inventions, and, without denying or admitting the validity of the latter, leave the inventors whose devices have been appropriated free to seek redress without prejudice in a judicial tribunal. (Berdan’s Case, ante.)

We do not decide that the tender of an express contract unaccepted by the other party bound the claimant; we do not decide that the naming of the compensation in that proposed agreement precluded him from seeking a higher one; we do not hold that it became the only evidence of'value which should be considered in such a case; but we are of the opinion that in this case, where the device was new and untried, where not a single sale of the license had been made, where its value in the market at the time rested entirely upon the opinion which Government engineers here and there in four or five countries of the world might set upon it, where the usefulness of every novel element in it was still conjectural, the proposed agreement of the two contracting parties constitutes the best element of market value that the case affords.

In giving effect to this action of the contracting parties we note the fact that the initial payment of 15,000 francs was placed at that amount on the express condition that it should be substantially immediate, and that the deferred payments were placed at 30,000 francs in consideration of the certainty of a binding agreement. On a review of all the facts of the case and taking into 'consideration the variance of the facts from the terms of the proposed agreement, such as the deferred payments, the increased uncertainty of the remuneration, the cost and delay of litigation, we are of the opinion that the parties would have agreed for the use of the invention in the three dams to which it has been applied upon a contingent consideration of deferred payments of about 130,000 francs, and we find the value of the ‘claimant’s royalty, so far as his invention has been appropriated and used, to be $26,000.

The court regrets the heavy expenses which the claimant has borne and the long delay to which he has been subjected, but the value of his device must be estimated as of the time when it was taken and at a price for which it could, then have been sold. '

The judgment of the court is that the claimant recover of the defendants the sum of $26,000.

Scoeield, J., sat in this case and took part in the decision, but was absent when it was announced.  