
    Mrs. Madeleine V. Dahlgren, Administratrix, v. The United States.
    
      On the Proofs.
    
    
      An officer in the Navy, on duty as an ordnance officer, makes experiments in gunnery. They are. in the line of Ms duty, at the cost of the government, and under the supervision of Ids superior officer. After an interval of several years the officer procures letters patent for his improvements thus worked out. Subsequently Congress pass an act referring the claim of his administratrix for guns manufactured under his patents to this court, with special instructions as to what shall be ascertained judicially.
    
    
      I. Where the government has a special defense to a claim, and the facts constituting- the defense are well known to Congress, it is unreasonable to suppose that Congress would refer the claim to this court with the intent that the special defense should he set up and the claim he defeated thereby.
    II. Where a special act directs the court, “first,” to ascertain whether the claimant was the “first and original inventor ” of certain inventions used by the government; ‘ ‘ secondly,” what amount of compensation, if any, the claimant is justly entitled to receive for the use of his inventions, &c., it will he held when interpreting the act that Congress intended to marshal under “first” those subjects that should be considered in harto the right of recovery, and under “ secondly ” those which relate to the amount of damages.
    III. Where Congress, by the passage of an act of reference, necessarily waive a certain technical defense and instruct the court to consider facts going to the merits, other technical defenses known to Congress will he deemed waived and the case adjudged upon the merits.
    IV. The history of the Dahlgren gun and of its adoption by the government examined and stated.
    V. As the special act referring claims for the Dahlgren gun does not enlarge the rule of damages, damages must he for the use of the patented invention, and not for the new system of armament devised by that officer of which his gun might have been an element.
    VI. Where the government has used and manufactured patented articles, but has not dealt in them, nor gained a profit from them in the ordinary commercial sense of those terms, damages may be assessed under the rule laid down by the Supreme Court in Suffolk County v. Mayden (3 Wall., 320).
    
      The Reporter's statement of the case:
    The soecial act referring tbe claims for the use of the Dahl-gren gun will be found in extenso in the opinion of the court. The following are the facts of the case as found by the court:
    I. John A. Dahlgren, the claimant’s intestate, deceased on or about the 12th July, 1870. The claimant was duly appointed administratrix; of his estate, and entered upon and still performs the duties of that trust.
    II. While the said Dahlgren was perfecting the inventions described in the complaint, and hereinafter referred to, he was in the service of the United States as an officer of the Navy.
    His rank in the Navy was as follows: From April 1,1848, to September 14, 1855, a lieutenant, on ordnance duty at Washington; from September 14, 1855, to March 4, 1857, a commander, on like duty; from March 4,1857, to May 28, 1858, a commander, in command of the Plymouth; from May 28, 1858, to December 8,1858, a commander, on duty in the Gulf of Mexico ; from December 8,1858, to April 22,1861, a commander, on ordnance duty at "Washington; from April 22,1861, to July 22, 1862, a commander, in command of the Washington navy-yard; and from July 22,1862, Chief of the Bureau of Ordnance in the Navy Department.
    III. During this period, the pay of the said Dahlgren in the said several positions was as follows : From April 1, 1848, to March 2, 1851, inclusive, as a lieutenant on shore duty, at the rate of $1,500 per annum; from March 3,1851, to May 31,1860, inclusive, under the provision of the act of March 3, 1851 (9 Stat. L., 622), at the rate of $2,500 per annum; from June 1, 1860, to December 31,1863, under the i>rovision of the act of June 1,1860 (12 Stat. L., 27), at the rate of $4,200 per annum.
    1Y. The condition of the Navy of the United States at the time when Lieutenant Dahlgren commenced the experiments hereinafter referred to is stated with substantial correctness in the following extract from an official letter from him to the Chief of Bureau of Ordnance and Hydrography in the Navy Department in Washington, dated October 15, 1849:
    “ With the exception of a single frigate, we have not a model •of a liner or frigate less antique than the third of a century; and, as a consequence, the powers of the smallest steamers with more modern appliances are disparagingly assorted over those •of the heaviest sailing vessels.”
    At the time of the introduction of the Dahlgren guns into the Navy of the United States, two ships in that Navy were armed with the old 8-inch shell gun of 63 hundred-weight, while the other ships were armed with 8-inch guns and partially with 32-pounders of 57 hundred-wmight and 42 hundred-weight. The 32-pounders were commonly known as the Wadsworth gun.
    The relative power at that time of the armamen t of said Navy, .as compared with that of the French navy, was also stated with substantial accuracy in an extract' from the same letter, in which he speaks of—
    “The significant fact that the French shell gun overmatches any shell gun in the broadside force of our ships from the line-of-battle ship down.”
    
      and to remove tbe inequalities between tbe American Navy and tbe navies of other powers, tbe said Dablgren addressed an official letter, on or about tbe 12tb day of July, 1849, to tbe Chief of Bureau of Ordnance and Hydrography in tbe Navy Department, in which be proposed to have an experimental gun constructed at the public expense from plans to be drawn by himself.
    YI. In tbe letter of October 15, 1849, to said chief of bureau, from which extracts have already been made, said Dablgren laid before said officer some reasons why be bad been led to tbe conclusion that there is a fixed relation between tbe mass of a shot or shell and its velocity which is essential to accuracy of flight, and why, as this relation is departed from, so will the deviations from the trajectory increase. He further deduced from this conclusion that, if it be desired to increase the momentum of ordnance, the mass must be increased as well as the velocity, and that the limit to extension will only be found in the weight of a gun or projectile too unwieldy for use. He also proposed to the bureau to furnish him with two guns for the purpose of making farther experiments — one a 50-pounder shot gun of about 8,000 pounds, the other a IN-inch shell gun of about 9,000 pounds.
    YII. The experimental guns then asked for were constructed by the government at its expense, the plans for the IX-inch shell gun being furnished by said Dablgren, and they were delivered at the Washington navy-yard in May, 1850. During the following season experiments at the public expense were made with them by the said Dahlgren at said navy-yard. On the 27th of January, 1851, he officially reported to said chief of bureau as follows:
    * * * *■ * » #
    “ The results have been highly satisfactory, and I think will fully confirm the idea presented to the bureau in Sept’r, 1849, namely :
    “That, in projecting shot, there is a velocity which cannot be exceeded without injuriously affecting the accuracy, so far as the purposes of sea ordnance are concerned.
    “2d. If, with this velocity, the momentum be insufficient, it must be increased by augmenting the mass and not the velocity. * * * "■ * * * *
    
    “I believe, therefore, that nothing is hazarded in saying that the true direction for future experiments should be to ascertain whether the most effective ordnance for ships is not—
    
      
      “ 1st. The heaviest pieces that can be manoeuvred on truck carriages, and those throwing the heaviest projectiles that can be conveniently handled.
    “2d. The weight of projectile to be distributed in the form of a shell, shot only to be used in exceptional cases, and then with low charges.
    “ 3d. To ascertain the precise term of velocity that ought not to be exceeded with these calibres in order to attain the greatest practicable accuracy.
    “ Without pretending to decide on the exact weights of piece or projectile that should be accepted as the highest within the limitations above noted, it may still be asserted that enough is ascertained to show that the ordnance question is sufficiently developed to make it expedient to have some data in regard to the ship that could carry such pieces.
    * m * » * # *
    
    
      u The form which has been used for the nine-inch gun is altogether independent of the calibre, and has not the least necessary connection with the principle on which the calibres proposed, the weight of guns, charges, and shells are based.
    * * *****
    “The times seem propitious to the development of our naval force hinted at in the foregoing lines. The system which thirty years ago was one step in advance of all is now behind the progress of England and even of France in naval affairs. The heavy ordnance of steamers has nullified the calibres now in vogue— 32-pdrs. and 8-in. shell guns. Public opinion at home seems to demand a forward movement in the material of our Navy, and from no source can this emanate with more propriety or advantage than from the Navy itself.”
    YIII. On the 18th of March, 1851, said Dahlgren submitted orally to the chief of said bureau a plan for an experimental XI-inch shell gun, constructed on the same principles as the experimental IX-inch gun, but thinner in the chase. On the following day, in compliance with the verbal directions of said chief, he transmitted to said bureau an official requisition for one of the class of 64-ponnders of 12,000 pounds then carried on the United States war vessels, and an official request for the construction of said experimental XI-inch shell gun according to plans furnished with the request. He said that he made these requests in order to carrj' on the practice at the experimental battery during the then coming season. The requisitions were approved, and an order was given for the construction of such experimental gun at Boston' at the public exp'ense. When the gun was ready for inspection Dahlgren was officially ordered to proceed to the manufactory at Boston to inspect it. The following are extracts from his report, elated October 18, 1851:
    -*• * * * # * #
    “ Under the regulations of the bureau, I was prevented from accepting the piece by the presence of some cavities in the bore. One or two of these near the muzzle were very apparent at 'first sight, and by the aid of a mirror another could be seen on the lower left quarter, seemingly near the insertion of the chase.
    “ After the proof by powder, which, by permission of the bureau, was ten service rounds, the piece was washed out and sponged, and in two or three hours examined by the mirror.
    “ So far as the bore was dried, the presence of damp spots in the chase were very evident. The day being nearly spent, the force-pump was applied with the usual pressure before leaving the ground.
    “The next day I returned about noon and examined the bore with a mirror. The surface was slightly rusted and dry, except in several spots extending along the chase, but not quite so far as the trunnions.
    ‘An insx>ector of ordnance, under these circumstances, has no discretion. The Kegulations expressly disallow any cavities in the bore, and also the mere indication of their existence, thus i ‘And if, on examination the day after the water-proof, there shall be any dampness by weeping in the bore the gun may be rejected.’ (Page 45.) *
    * * * * * * & %
    
    “As the gun is not intended for service, but for experiment, it may properly remain for consideration whether the very reasons, on account of which it would be rejected for service, may not be sufficient to induce its acceptance for experiment. For, independently of the question of ultimate strength, there are others more important in respect to the accuracy, force, and range of this caliber, as well as the practicality of conveniently handling the weight of gun and projectile, which ought not to be delayed. And as the people can always be withdrawn to a safe distance, no risk of life need be incurred.
    IX. In the spring of 1853, the said IX-inch shell gun was, on the official suggestion of said Dahlgren, sent to Old Point. Comfort and there tested to the extreme. It burst after enduring a firing of 1,006 rounds, of which 228 took place after a crack had been developed. Dahlgren reported to the chief of said bureau that the result demonstrated clearly that the metal had not been sufficiently reduced at the chase.
    X. In March, 1853, Dahlgren requested the casting of a second experimental IX-inch gun. Its proportions corresponded to those of the XI-inch and to those of the forward part of the VIII-inch, but differed from the IX-inch experimental No. 1 in being longer. Its weight was substantially the same as IX-inch No. 1. The following are extracts from Dahlgren’s letter, dated May 3, 1853, transmitting the drawings for said last-named gun:
    * * # # # & #
    “It remains to ascertain whether the weight of the piece makes it unmanageable at sea under such circumstances as actions are generally fought. This can only be tested on shipboard, and I therefore would request that two pieces be cast upon the draft now sent, and tried at sea by mounting them temporarily on the main deck of a frigate in lieu of any two of the guns now carried.
    “ Herewith I forward, as directed, a copy of the paper which, at the instance of the naval committee, was drawn up by your order, and I again most respectfully solicit the attention of the bureau to the important interests involved in the problem therein presented.
    “ The policy which has guided the progress of our Navy as best adapted to its extent and character would of itself be a sufficient reason to advance in the direction indicated by the proposed change, but the choice seems now to be no longer at disposal, because the increasing power of the English and French batteries makes it a matter of absolute necessity.
    “ I do not mean to lose sight of the fact that, since the paper for the naval committee was drawn up, some changes have been made by the bureau in the batteries of the frigates and line-of-battle ships, by removing the light shell guns from the spar •decks and increasing the number of the heavier pieces of the same •class on the gun decks so as to constitute upon each an entire -division of 8-in. shell guns of 63 cwt. (7,000 lbs.). But this can ■only be regarded as a more judicious arrangement of existing forces, and by no means remedies the inherent inferiority of our present batteries; because that inferiority arises from a defect in principle. The Independence, for instance, or the Congress, with their armament (long 32-pdrs. and 8-in. shell guns of 7,000 lbs.), would be held at a vast disadvantage by the long and heavy 68-pdrs. of the British frigate Arrogant or by the additional long 50-pdr. of 10,000 lbs. which the French frigates carry on the main deck in connection with shell guns more powerful than our own. The long 64-pdrs. of heavy steamers in our own or other navies would also frequently endanger our frigates as now armed.
    “The armament of the Macedonian is a very decided improvement upon that formerly carried by her, and at moderate distances would act with great power, but sbe does not carry a gun that could match a French long 50-pdr. or an English 68-pdr. The 10-in. guns mounted above are too light for long range — the shells fired from them weigh 100 lbs. each, and the charge of piece is only 10 lbs., while below are shells of half the weight (8 shells of 53 lbs.), fired with charges nearly as great.
    “ On the other hand, if our frigates be armed as proposed in the paper sent herewith, no force now carried by sailing or steam frigates could engage one of them with any hope of success.
    “These remarks are not made without reflection nor without sufficient facts; they are the result of long practice with nearly every one of the numerous classes of naval guns and with the heavier pieces proposed. The magnitude of the interests involved urge me to appeal most earnestly to you, and I assure you that nothing but the deep anxiety I feel upon the subject would induce me to press it so far as I have done. And I am encouraged particularly to do so at this time because in framing the estimates for the coming fiscal year (commencing July 1st) you thought proper so far to entertain the matter as to include therein the cost of 20 nine-inch shell guns, and six eleven-inch shell guns, and the authority to act is therefore properly within the executive discretion.”
    NI. On the 18th May, 1853, said last-named IX-inch gun was contracted for by the United States at a cost of $159 per ton of 2,240 pounds. When completed, Dahlgren inspected it officially, under orders from his superior. The force and material necessary for such inspection were furnished from the navy-yard in New York.
    XII. On the 28th November and the 7th December, 1854, respectively, the Chief of the Bureau of Ordnance approved of draughts of an XI-inch and a IX-inch shell gun submitted by Dahlgren. The XI-inch gun in its proportions corresponded with the XI-inch experimental shell gun approved March 24, 1851, and the IX-inch with the second experimental IX-inch gun authorized March 12, 1853. The dimensions of the two guns relatively to the bore were the same.
    XIII. Under the Appropriation Acts of April 6,1854 (10 Stat. L., 273), and March 3, 1855 (10 Stat. L. 676), it was determined to construct six steam frigates for the Navy, and to arm them in part on the system recommended by said Dahlgren, and with the Dahlgren guns. The chief of said bureau directed said Dahlgren to submit an outline of terms by which the government would be best assured of good cannon for the Niagara. He complied with, the instructions in a letter dated November 24, 1855, in which, among other things, he suggested the following as terms to be imposed upon the persons contracted to cast them:
    
      # * * * * # *
    “8th. The founder will estimate and make known the price which he will charge for making the number of guns that may be ordered. This will be either accepted or modified, as may be agreed upon by him and me, and the proof gun shall be paid for at this rate when inspected and received as above.
    # # # * # # * »
    “14. Any of these guns cast under this or other contracts, which shali be rejected, shall be broken up, and the contractors will neither use these models nor permit them to be used, nor any particular of their construction, or mode of production peculiar to them.”
    * * * # * * *
    XIV. The chief of said bureau in submitting these terms to the contractors struck out the words “by him and me” from the eighth condition, and changed the fourteenth condition so as to read:
    “Any Xl-in. guns cast which shall be rejected shall be broken up. The contractors will neither use these models nor draughts, nor permit them to be used, nor any particular of their construction, or mode of production peculiar to them.”
    Thereupon said Dahlgren wrote to the said chief of bureau two letters, from which the following are extracts:
    “I respectfully submit that the effect of omitting the words “by him and me,” in the 8th condition, will be to deprive me of one of the most essential requisites for insuring the goodne.ss of the Xl-in. guns in question, and will defeat the intentions of the honorable Secretary of the Navy, expressed in your letter of November £2d, 1855.
    “The only other change in the terms of the “proposition,” which I regard as important, is that made in the 14th article, concerning the breaking up and subsequent disposal of the cannon made upon my model.
    “The conditions offered by the proposition I have submitted appear to be exceedingly favorable to the founders; and as a number of IX-in., X-in., and Xl-in. shell guns now remain in their possession, by reason of most unexpected failure to meet the previous requisition of the bureau, the occasion seemed opportune for making some provision against these pieces and the mode of construction being disposed of against my own wishes at least, even if the government should be indifferent thereto.”
    
      XV. The chief of said bureau made replies to said last-named letters, of which the following are extracts, viz, to that relating to the eighth condition as follows :
    <l On reference to the Secretary, you are now authorized to understand that the department will not refuse to agree to any price which, in its opinion, would not justify the refusal to purchase such guns at all.
    “It is well understood that your propositions, combined with the small number of guns to be furnished, will impose increased expenses upon those who are to furnish the guns, and to obtain them the department is willing to meet such expenses and a fair and reasonable profit to the makers.
    And to that relating to the fourteenth condition as follows:
    “The prohibition to use the models of the Xl-in. guns contained in the 14th article was not extended to those of IX-in. and X-inch by that article, because they did not appear to have any immediate connection with the mode of making the XI-inch guns, and because the officers on duty at the several foundries had been instructed on the 4th of June last to notify the contractors that the plans of all of these guns were to be kept from the inspection of strangers, and their dimensions were not to be given to any one without the special permission of the bureau.”
    XYI. Under the Appropriation March 3,1857 (11 Stat. L.,244), the ordnance ship Plymouth was fitted out at the Washington navy-yard with a view to the improvement of ordnance and gunnery practice, and said Dahlgren was assigned to command, as before stated. On the 7th July, 1853, the vessel went to sea on a six months’ cruise. Her armament consisted of four IX-inch shell guns, one XI-inch shell pivot gun, two 24-pounders, and ■one 12-pounder howitzer. The result of the cruise dispelled all ■doubt whether the heavy cannon which she carried would be manageable; and, in the opinion of the Secretary of the Navy, not only justified the adoption of the ordnance on the steam frigates then recently built, but also rendered it expedient to extend that plan of armament.
    XVII. Among the contractors who received the notices of terms referred to in Findings XIII, XIY, and XY, were Alger & •Co., of Boston. It came to Dahlgren’s knowledge that they had, without permission, sold to the Russian Government guns apparently like the Dahlgren XI-inch gun. He complained of it to said chief of bureau; Alger & Co. denying that the guns sold to Russia were after the Dahlgren model. Dahlgren, on the 20fch. April, 1859, wrote a letter to tire Secretary of tbe Navy, from which the following is an extract:
    # # #• * # * *
    “The only difference that exists is in the diameter of bore; that of the United States is 11 inches exactly, while the pieces in question weremadeby Alger and Go. to conform to a Bussian calibre, which is one-quarter of an inch less. The weight of gun is also marked 400 lbs. less, which might have been due to the compensation required to maintain the preponderance.
    “But neither the difference of one-quarter of an inch in cali-bre, nor of 400 lbs. in weight, could exert the slightest influence in changing a model which in all else, as already shown, follows-a certain standard.
    “For model is not confined to calibre, which may be IX-in., X-in., or XI-in., and if the being 10f inches is designed to justify the assertion made by Alger & Co., it would not be considered otherwise than as an evasion.
    “ The breach of faith thus committed is an encroachment on the right of property to my grievous detriment, for after the service of a life in my profession, this alone constitutes the entire dependence of my children, if accident should deprive them of my assistance.
    “ It matters little how difficult it might be to preserve this; there is no justification in that for a breach of faith to the government, and the wrong done to me.
    “I trust, therefore, that the department will not permit this firm to manufacture any more cannon of my model under future contracts.”
    XVIII. On the 16th March, 1859, said Dahlgren made application for a x>atent for a new and useful improvement in cast-iron ordnance, and on the same 16th March paid the requisite-fee therefor. The specifications and drawings were returned to him on the 28th of the same March. Subsequently they were refiled, and patent No. 32983 was issued to him thereon on the 6th August, 1861. The specification of the patent is as follows:
    “To all whom it may concern:
    “Be it known that I, John A. Dahlgren, of the city and county of Philadelphia, in the State of Pennsylvania, have invented a new form for cast-iron ordnance, which consists in so-shaping a gun a-s to dispose all the .metal available for the purpose about the part where the greatest, if not the whole, force of explosion is exerted when the gun is discharged, whereby I am enabled with a given quantity and quality of iron to make cannon which shall throw heavier projectiles and a greater aggregate weight of them than cannon constructed by the rules, hitherto practiced.
    
      “ In tbe accompanying drawings, Figure 1 represents a side elevation of gun constructed in tbe improved form invented by me; and
    “Fig. 2 represents a longitudinal section of tbe same.
    “For convenience of description I have divided tbe gun into four sections, bounded as shown by tbe lines 1, 2, and 3, in Figure 2. Tbe part between tbe end of breecb and line 1,1 call tbe breech. Tbe part between tbe lines 1 and 2,1 call tbe fort.
    
    “ The part between tbe lines 2 and 3,1 call tbe junction; and tbe part between tbe lines 3 and tbe muzzle, I call the chase.
    
    “ Tbe unit of measurement which I have employed for tbe construction of tbe gun is tbe diameter of its bore, or, as ,it is generally called, tbe calibre of tbe gun; and however large or small may be tbe piece of ordnance which it is required to construct-, tbe dimensions of its several parts will be expressed in multiples or fractions of its own calibre corresponding to tbe proportions of tbe gun laid down in Figure 2, whose dimensions at important parts are denoted in units of length equal to its own calibre; provided that tbe quantity of powder with which tbe new gun is to be fired bears tbe same relation to tbe weight of its projectile that exists between powder and projectile for which the gun shown in Figure 2 is designed; tbe proper weight of tbe projectile for which is a shell or hollow spherical ball, about three-quarters of tbe weight of a solid spherical ball of tbe same calibre to be fired with about one-seventh its weight of powder.
    “For example, it is required to make a cannon having a bore eight inches in diamter. Tbe following dimensions are obtained from tbe drawing annexed:
    Calibres.
    Length from face of muzzle to end of breecb.. 13. 511
    Length of breecb. 1. 511
    “ of fort... 2.380
    “ of junction. 2.778
    “ of chase. C. 833
    “ of bore. 12. 000
    “ By tbe same rule tbe diameter of the several sections of tbe gun would be—
    At lines 1 and 2. 3. 022
    “ line 3.'. 2.030
    “ muzzle. 1. 400
    “By tbe same rule, also, tbe weight of tbe projectile and of tbe powder would be as follows, viz:
    Shell, empty. 70 lbs.
    Powder. 10 lbs.
    “ If, however, tbe weight of tbe charge of powder is to be materially less than one-seventh of that of tbe shell or other projectile, then the diameters at 1 and 2 may be reduced to 2.909 calibres, and the length of breech to 1.455 calibres, and the breech may have an ellipsoidal instead of a spheroidal form.
    “In like manner the dimensions in calibres of all the other parts may be obtained by measuring the drawing in Figure 2.
    “ In smooth-bored cannon the form of the breech may be hemispherical, hemispheroidal, or ellipsoidal, as greater or less strength is required.
    “Strictly speaking, the surface of the fort should be curvilinear longitudinally as well as transversely; but as artiller-ists insist on the importance of having the means of taking a direct level aim for point-blank firing, in case of injury to the sights, the fort of the gun represented in the drawings is made cylindrical, the diameter being forthat purpose slightly reduced between the points 1 and 2.
    “Another deviation from strict theoretic proportions is produced by a swell about the muzzle, chiefly to protect it from liability to fracture by being struck against, or by hard bodies. This swell also answers another purpose, especially useful on board ships, of giving a hold for a lashing in case the gun is housed.
    “The trunnions and other projections may be cast on in the usual way, but the strength of the gun will be much increased if it is cast without them; and they can be attached subsequently by a method a more particular description of which is given in another patent granted to me and bearing even date herewith.
    “ What I claim as my invention, and desire to secure by letters patent, is a cast-iron gun constructed substantially according to the rule herein described, whereby the quantities of metal disposed in the different parts of the gun are proportionate, or nearly so, to the relative degrees of strain exerted by the force of the exploded charge at those parts respectively.
    “ In testimony whereof I have hereunto subscribed my name.
    Jno. A. Dahlgren.
    “ Witnesses:
    “A. B. Norton.
    “Jno. D. Brandt.”
    The court finds that said Dahlgren was the first and original inventor of the invention described in said patent, and that his said invention had novelty and utility and value, and that it has been used by the United States as set forth in these findings.
    XIX. On the 19th July, 1861, said Dahlgren applied for another patent for a new and useful improvement in such ordnance, and on the 19th and 26th of the same July he paid the requisite fees therefor, and patent No. 32984 was issued to him tbereon on tbe 0th August, 1861. The specification of said last-named patent is as follows:
    “To all whom it may concern:
    “Tte it known that I, John A. Dahlgren, of the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful improvements in the construction of cast-iron ordnance, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which make part of this specification, and in which—
    “ Figure 1 represents an elevation of the side of one of my improved guns, finished; and
    “ Figure 2 represents an elevation of the side of the rough casting or blank as it comes from the mold and before the finishing is commmenced.
    “To produce cast-iron ordnance of the greatest strength it is necessary that the moulten metal after being poured into the mold should cool with evenness and regularity throughout the entire length of the gun; to effect which it is indispensable that the diameters of the casting should vary as little as possible, and that the external surface should be uniform and free from prominences of any kind, or at least from such as have material volume; if not, the mass cools and solidifies first where its diameters are least, and afterwards where they are greatest, and the parts which cool last shrink from the parts which cool first, thereby straining the metal and diminishing its strength. The largest portions being located at and near the parts of the gun surrounding the charge renders it less callable of resisting the force of the explosion, which exerts nearly all, if not the whole, of its power within what I have termed the fort of the gun, or that part surrounding the charge.
    “ Prominences of any kind also cool first and cause irregularity of contractile strains in their vicinity, which are highly detrimental if of material volume. For this reason, as well as from their locality and consequent effect upon the breech, the cascabel and trunnions should be made separately and after-wards attached; and the rear portion of the gun, including the fort, should be of a substantially spheroidal or ellipsoidal form, as indicated by the red lines in Figure 1, which represent the section of a prolate spheroid in a plane parallel to its long axis.
    “To contribute still further to rendering the metal homogeneous the mold should be surrounded by a layer of charcoal or other slow conductor of heat, so as to render the cooling and solidification of the different portions of the gun more slow and even.
    “After the casting has been slowly and thoroughly cooled, it is to be bored of the proper caliber, and its exterior turned down until reduced to the proper size, according to a rule of construction (in wbicb the diameter of the bore is the unit of measure) invented by me, and fully described in another patent bearing even date herewith, and which need not therefore be described.
    “The size and shape of the rough casting at the breech and fort, or the parts surrounding the charge, when the gun is loaded, should be precisely such as are required in the finished gun, for as here occurs the greatest force of the explosion when the gun is fired, it is very desirable to retain the crust or outer shell of the casting intact, as it is much stronger and tougher than the interior metal and conduces materially to the strength of the gun where strength is most needed.
    “The reduction of the rough casting should therefore be made between tbe forward part of the fort of the gun and the muzzle; and the finishing should be so executed as to leave the gun with a smooth surface and gradually decreasing mass from the region around the charge to the muzzle, tree from all moldings or ornamentation that would interrupt or disturb the waves of vibration that traverse the gun when discharged and occasion or accelerate its rupture.
    “A slight swell.of the ordinary form has been retained about the muzzle to fortify it against accidental blows which might fracture metal so thin as that of the muzzle would be if the rule of construction before referred to were followed rigidly.
    “It is to be understood at this portion, of the gun, so remote from the charge, the danger due to a slight departure from the law of construction, though existing, is less than that which would arise from the exposure of the muzzle, unprotected by a swell, to heavy blows. The swell is therefore to be regarded as the lesser of the two evils.
    “ What I claim as my invention, and desire to secure by letters patent, is the method herein described of manufacturing cast-iron ordnance by first casting it in the rough of such proportions as will give the metal the most tenacity and freedom from contractile strains, and then reducing the casting to such proportions as will produce the form of a gun best calculated to endure the shocks of discharge.
    “I also claim the manufacture of cast-iron ordnance, substantially as described, with the rear portion thereof of a substantially spheroidal form and the exterior surface smooth and free from moldings and other ornamentation with which guns have heretofore been made.
    “In testimony whereof I have hereunto subscribed my name.
    “John A. Daiilgren.
    “Witnesses:
    “A. B. Norton.
    “Jno. D. Brandt.”
    
      Tlie court finds that tbe said Dahlgren was also the first and original inventor of this invention, and that said last-named invention had novelty, utility, and value, and that it has been used by the ITnited States as set forth in th ese findin gs.
    XX. On the same 19th July said Dahlgren applied for another patent for an improvement in such ordnance; and on the 6th August, 1861, patent No. 32985 was issued to him on such application. The said Dahlgren was the first and original inventor of the invention patented thereby, but such invention neither had nor has any utility or value.
    XXI. On the same 19th July said Dahlgren applied for apatent for an improvement in projectiles for rifled ordnance; and on the 6th August, 1861, patent No. 32986 was issued to him on said last-named application. Said Dahlgren was the first and original inventor of said last-named invention, but the same neither had nor has any utility or value.
    XXII. The gun described in said specification of patent No. 32983 is in principle identically the same, and in detail substantially the same with that invented by said Dahlgren and constructed in accordance with his plans in 1850, as heretofore set forth. Guns constructed on this principle were first introduced into the Navy of the United States in the said steam frigates constructed under the said appropriation acts of April 6,1854, and March 3,1855. They have been in use in the naval service of the United States since that time, and still form a large [part of its armament. The total number of such guns used in the service is 3,948, weighing in the aggregate 23,453,160 pounds.
    XXIII. The gun invented by said Dahlgren proved of great advantage to the United States, by reason of its larger shell to the same amount of metal, of its greater safety, of its greater power, of its economy in powder, and of its requiring a smaller number of men to the same amount of metal. But its value was greatly increased by the general change in the system of arming-war vessels, which was made simultaneously with the introduction of the Dahlgren gun. This change, in the form which it assumed in the Navy of the United States, was largely due to the genius of Admiral Dahlgren; but it was also superinduced by changes simultaneously taking place in foreign navies, and was made in order to enable the American Navy to compete with those navies in efficiency.
    
      XXIV. Taking into consideration the facts as hereinbefore found, that while said Dahlgren was engaged in perfecting said inventions he was in the service of the United States as an officer in the Navy, and that the expense of making experiments, trials, and tests for the purpose of perfecting said inventions was paid by the United States, the amount of compensation which the estate of said John A. Dahlgren is justly entitled to receive from the United States for the use of his said inventions, either before or since the date of said letters patent up to the day of this adjudication, and for a full and entire transfer of said letters patent to the United States is sixty-ñve thousand dollars. In finding this amount no regard is had to patents Nos. 32985 and 32936, because the same are held to be valueless.
    
      B. T. Merriclc and Jf. F. Morris for the claimant:
    That the claimant is entitled to some compensation for the use of these inventions by the United States is very evident.
    This right is founded upon general principles, and the act of Congress is itself a special recognition of the right. The case of McKeever v. The United States, we presume, will be accepted as settling the general principles applicable to the present case; and that, too, without any occasion for dissent as was there presented by the character of the proof in the case.
    It is now unquestionably a well-established principle of law that a patent is private property, under the protection of the Constitution of the United States, and as much entitled to protection as any other property; and that government cannot take such property and make use of the invention, any more than a private individual, without license of the inventor or making him compensation. (Gommeyer v. Newton, 94 U. S. R., 225; United States v. Burns, 12 Wall., 246; United States v. Bussell, 13 Wall., 623; Seymour v. Osborne, 16 Wall., 516; Miteh-ell v. Harmony, 13 How., 115; MeGlurg v. Kingsland, 1 How., 202; McKeever v. United States, 14 O. Ols. R., 396, Aet Congress of July 8, 1870,16 Stat. L., 198; Rev. Stat., § 4884.)
    The fact that Admiral Dahlgren was an officer in the naval service of the United States does not preclude him or his estate from recovering from the United States the value of the use of his inventions. This point was directly decided by the Supreme Court of the United States in the case of the United States v. Burns (12 Wall., 252).
    
      But under tbe act of Congress referring this case to this court, it does not matter whether Admiral Dahlgren ever received any patents at all. If the inventions were his, compensation is authorized by the act, even Avithout any patents.
    
      Mr. John S. Blair (with whom was the Assistant Attorney-General) for the defendants:
    The act of June 19, 1878, provides :
    “And in determining the right of said estate to recover the amount of compensation to be paid said estate for the use of said inventions and the transfer of said patents, the court shall take into consideration the facts, if proven, that while the said John A. Dahlgren was engaged in perfecting the inventions he was in the service of the United. States as an officer in the Navy, and that the expense of making experiments, trials, and tests for the purpose of perfecting such inventions was paid by the United States.”
    It will be observed that these facts are to be considered not in determining the amount of the compensation, but in determining the right of recovery. With this in view, no effort has been made to shoAV what the different guns and experiments cost, nor even to place before the court all the experiments which aided Dahlgren in reaching his conclusion.
    The salient facts, however, are—
    The experiments by Bomford & Wade, in 1843, of which Dahlgren availed himself, paid for by the United States.
    The experimental practice with the 33-pounder, which culminated in November, 1849, in its explosion.
    The casting of three experimental guns and the turning down of a fourth.
    Repeated firing with these gnus.
    Calling in Admiral Farragut, with his experience and knowledge, to aid in tlie investigation by the intentional bursting of two of the experimental guns.
    Increasing Dahlgren’s salary while these experiments were going on.
    Under all these circumstances, the question naturally arises, were all these guns cast, was the powder and ball furnished, were clerks and gunners directed to assist, and Mr. Farragut called in for Mr. Dahlgren’s individual benefit ?
    The case comes within the very exception of the Burns Case 
      (12 Wall., 252), for Dablgren was an officer in the naval service, specially employed, to make experiments with a view to suggest improvements, and he received $1,000 additional per annum as special pay for this, service. In Bloxam v. JSisee (1 Carrington & Payne, 558) the defendant contended inter alia that the patentees (plaintiff’s assignors) were not the inventors, but Mr. Donkin was. Mr. Donkin stated that the improvements were his invention, but that at the time he invented the improvements he was employed by the patentees as an engineer for the purpose of bringing the machine to perfection, and was paid by them for so doing, and, therefore, he was acting as their servant for the purpose of suggesting inprovements.
    The ])laintiff failed to recover on another ground (9 Dowling & Eyland, 215), but the court seemed to be of opinion (1 O. & P., 566) that the employment of Donkin for the express purpose of devising improvements vested in his employer a right to the result of his labors.
    In Wheaton v. Peters (8 Peters, 588, 668), the Supreme Court was unanimously of opinion that no reporter can have, nor can the court confer, any copyright in the written opinions of the court.
    The present case seems to me analogous to an attorney-general or a judge of this or of the Supreme Court copyrighting opinions delivered in the discharge of his duty. The taking out of the patents in this case was an afterthought of Dahl-gren’s, and he seems for many years to have gone on the theory, which I maintain is the correct one, that the fruits of his labor belonged to his employer.
   Davis, J.,

delivered the opinion of the court:

The statute which sends this case here lays down rules for its trial and the principles which shall govern the court in deciding it.. The act provides:

“That the claim of Madeleine Vinton Dahlgren, ás adminis-tratrix of the late Eear-Admiral John A. Dahlgren, for compensation for the adoption and use by the Government of the United States of certain inventions relating to ordnance, made by the said John A. Dahlgren, and for which letters patent of the United States, numbered thirty-two thousand nine hundred and eighty-three (32983) thirty-two thousand- nine hundred and eighty-four (32984), thirty-two thousand nine hundred and eighty-five (32985), thirty-two thousand nine hundred and eighty-six (32986), were issued to him, be, and the same is hereby, referred to the Court of Claims, which court is hereby vested with jurisdiction in the premises, and whose duty it shall be to hear and determine:
“First, whether the said John A. Dahlgren was the first and original .inventor of the inventions described in said letters patent, or any of them; and if they shall find that he was such first and original inventor of any-of the same, then to determine,
Secondly, what amount of compensation, if any, his estate is justly entitled to receive from the United States for the use of his said inventions, or any of them, either before or since the date of said letters patent, up to the time of adjudication, and for a full and entire transfer of said several patents to the United States; and in determining the right of said estate to recover the amount of compensation to be paid said estate for the use of said inventions and the transfer of said patents, the court shall take into consideration the facts, if proven, that, while the said John A. Dahlgren was engaged in perfecting the inventions he was in the service of the United States as an officer in the Navy, and that the expense of making experiments, trials, and tests for the purpose of perfecting such inventions was paid by the United States: Provided, That in no event shall such Court of Claims allow for the use and transfer of said patents, on the basis aforesaid, a sum exceeding sixty-five thousand dollars ($65,000); but said sum shall not be diminished pro rata in case the claimant fails to establish the novelty, use, or value of any of said patents.
Either party may appeal to the Supreme Court of the United States upon any such question where appeals now lie in other cases, arising during the progress of the hearing of said claim, and from any judgment in said case, at any time within ninety days after the rendition thereof; and any judgment rendered in favor of the claimant, as such administratrix, shall be paid in the same manner as other judgments of said Court of Claims; and the payment of such judgment shall vest the full and absolute right to said patents, and each of them, in the United States.” (Act June 19, 1878, 20 Stat. L., p. 583, ch. 357.)

From the language of this act it would naturally be inferred that, after passing upon the originality of the invention, we are then ” — that is, at once — to enter upon the question of damages.

The Attorney-General, however, contends otherwise. In an ingenious and forcible argument he urges that the instruction to the court that the fact of Dahlgren’s being in the Navy while perfecting his inventions, and of the payment of the cost of the experiments from the Treasury are to be taken into consideration in determining the right of his estate to recover; that the statute explicitly directs us to consider them in connection with the question, not of the amount of damages, but of the right of recovery. ,

If we accept this construction of the act, the claimant’s case comes to an end almost as soon as it begins. Lieutenant Dahl-gren was an officer in the Navy, on duty at Washington as an ordnance officer when these experiments began. They were conducted by him in the line of his duty, at the public expense, under the constant supervision of his superior, to whom he reported every step, and with a view to improvements in the ordnance for the Navy. While they were going on his pay was increased by special act of Congress beyond that of other officers of his rank on duty on like shore service. Their results were reported to Congress by the Secretary of the Navy. Special appropriations were made for conducting them on a larger scale at sea. All tírese facts were, through. statutes of the United States, through reports of the Secretary of the Navy, and through other documentary proof, known to Congress when it passed this act. They are, if not waived, a complete defense here.

If Congress had intended to set this defense up, it is more reasonable to suppose that it would have done so itself rather than put the claimant to the cost of a suit in order to have it set up here. And when we consider that it apparently intended under the word First ” to marshal all the subjects which were to be considered in bar to the right of recovery, and under the word “ Second” all those relating to the amount of damages, this arrangement and collocation of the legislative instructions, taken in connection with the previous probabilities, raise the strongest presumption against the Attorney-General’s construction.

In order to avoid this result, he is obliged to separate from the act that portion upon which he relies, and to regard the remainder as surplusage. If he is correct, the effective words of the act are “ in determining the right of said estate to recover, the court shall take into consideration,” &c., and the words “ the amount of compensation to be paid said estate for the use of said inventions and the transfer of said patents ” have no force whatever.

His argument meets witli a further difficulty iu the consideration that there was a dedication of Dahlgren’s inventions before the patents were issued and that that defense is waived by Congress. It does not seem probable that the legislature would waive the defense of dedication and instruct the court to consider the facts insisted on by the Attorney-General in bar.

All this leads irresistibly to the conclusion that the only way in which we can give force to the words which the Attorney-General’s construction expunges from the statute, and can make the act conform to the probable wishes of Congress, is by construing it as a direction to the court to consider the facts referred to, if proved, in determining what amount of compensation Dahlgren’s estate has a right to recover.

It is found that Dahlgren was the first and original inventor of all the inventions described in the patents referred to in the act j but that those described in Nos. 32985 and 32986 had no utility ■or Aralue. This leaves for consideration only the inventions described in Nos. 32983 and 32984. The claim under No. 32983 was for the completed gun of the form and proportions known as the Dahlgren gun, of whatever caliber it might be made» The claim under No. 32984 was for a form of casting for the manufacture of that gun, by means of which it was claimed that a greater uniformity in strength of metal could be attained than by the forms previously in use. This general statement of the nature of these inventions is sufficient for the purposes of this opinion.

The United States have made extensive use of these inventions. In all, they have manufactured or caused to be manufactured, and have used 3,948 Dahlgren guns, of an aggregate weight of 23,453,160 pounds. In determining what they ought to pay for such use and for the transfer of all the patents, after settling the extent and value of the use in the past, and the probable value of the remainder of the term, we are required ta take into consideration the proved facts that during the whole period in which Dahlgren was engaged in perfecting his inventions he was in the service of the United States as an officer in the Navy, and that the expense of making the experiments* trials, and tests for the purpose of perfecting the inventions was paid by the United States. But before determining the ■amount of the compensation, we have first to decide a preliminary question which came up in argument as to the subject fox' which compensation is to be given.

About the time of the beginning of Dahlgren’s experiments, important changes were going on in the naval armament of the world. G-uns of a larger caliber were being introduced, whereby the number of guns in the armament was diminished, and the force necessary to handle them was decreased. The proportion of shell guns to shot guns was at the same time increased. These ideas did not originate in the United States,, nor were they peculiar to any service. Dahlgren had the fullest faith in them, and this faith buoyed him up and led him on to success. In conceiving and perfecting his invention he was influenced by patriotic motives only. The record shows that he asserted no title in* his inventions until he saw the gun which he had invented about to be put into use in a foreign service with the assent of his own government. Hia only wish seems to have been to arm the service of which he was so distinguished a member with effective gxins, and to combine those g'uns together in the most effective manner.

Under his inspiration and direction the ideas which had taken hold of naval constructors in Europe were introduced into' the American Navy in the new steamships constructed under the appropriations made in 1851 and 1855. The success of this experiment caused an entire change in the armament of the vessels of war in the Navy of the United States. By means of this the government made a large annual saving in the force employed for working the batteries. In the series of years which have elapsed, this saving has grown to be far in excess of the sum fixed by Congress as the maximum for the judgment in this case.

The counsel for the claimant contend that, inasmuch as Dahl-gren’s patented inventions were used in the application of the new mode of ax’mament, this saving is the true measure of compensation. The Attorney-General answer's, and the answer is conclusive, that the saving is effected by the mode of combining guns of a large caliber, and that it can be effected, and in fact is effected, in other services, by combining guns of a large caliber which are not ^Dahlgren guns. So far as the combination was made in the United States, it undoubtedly came lai’gely from Dahlgren’s brain; but in suggesting it he acted only in the line of his ordinary duty, and Oougress did not intend to specially reward liim for it. The act directs us to find and award a compensation for the use of patented property, not ■a reward for the success of a suggestion made in the line of professional duty.

The materials for estimating the damages, or, in the language •of the statute, the amount of compensation which Admiral Dahlgren’s estate is justly entitled to receive from the United States, are meager. The xoatented articles have no market value, inasmuch as the United States is the only consumer. Therefore the inventor has lost no profits in the ordinary sense of the term. The inventor has made no licenses to any one, and had therefore no fixed royalty. The claimant, it is true, attempted to establish the reasonable worth of such a royalty on the basis of the weight of metal in the pieces; but the effort failed. The United States have not dealt in the articles, and have not used them so as to gain a profit in the ordinary commercial sense of the term. We are therefore thrown back upon the rule laid down in Suffolk County v. Hayden (3 Wall., 320), and must find the measure of the claimant’s compensation in “the utility and advantage of the invention to the United States over the old modes or devices that had been used for working out similar results ”.

The findings enumerate the advantages which the United States have gained by the use of Admiral Dahlgren’s inventions in the following language:

“The gun invented by said Dahlgren proved of great advantage to the United States, by reason of its larger shell to the same amount of metal, of its greater safety, of its greater power, of its economy in powder, and of its requiring a smaller ntimber of men to the same amount of metal.”

Some of these qualities can be weighed and estimated; others cannot be measured by a money standard. The act, which is our chart, shows that in the opinion of Congress the worth of all combined may reach the sum of $05,000. We have no difficulty in fixing it at that amount.

The judgment of the court is, that, taking into consideration the facts that while the claimant’s intestate was engaged in perfecting the inventions set forth in the complaint he was in the service of the United States as an officer in the Navy, and ■that the expense of making experiments, trials, and tests for the purpose of perfecting such inventions was paid by the United States, tbe claimant shall have and recover of and from the United States the sum of sixty-five thousand dollars in full for the compensation which the estate of said Dahlgren is justly entitled to receive from the United States for the use of said inventions, or any of them, either before or since the date of said letters patent up to the time of this adjudication, and for the full and entire transfer of said patents to the United States.  