
    REGINA CLEARY MONTGOMERY, HEIR, AND RICHARD J. MONTGOMERY, MARY C. MONTGOMERY, MARGARET H. MONTGOMERY, AND JANE E. MONTGOMERY, ASSIGNEES OF ELLEN MONTGOMERY, HEIR OF JOHN J. MONTGOMERY, DECEASED, v. THE UNITED STATES
    [No. 33852.
    Decided May 28, 1928]
    
      On the Proofs
    
    
      Patents; infringement; anticipation. — Oral testimony alone is insufficient and unreliable for the purpose of showing anticipation as against issued letters patent.
    
      Same; pioneer invention. — (1) Unless an inventor has a patent which performs a function that was not performed before, he is not a pioneer inventor, and his claims are not to be accorded a broad construction.
    (2) The courts have uniformly taken into consideration, in the construction of claims for which basic invention is claimed, the question of the general and practical utility of the device asserted to be pioneer in character.
    
      Same; construction of clami. — Under the patent statutes the claims of the patentee define the patent, and when the language used is not obscure or ambiguous and has a settled meaning, the courts are not at liberty to enlarge the same by construing them to intend something different.
    
      Same; Montgomery patent for aeroplane. — (1) Claims 4, 16, and 28, dealing with change in wing curvature to accomplish equilibrium and lateral control, of Letters Patent No. 831173 for aeroplane, granted to Montgomery September 18, 1906, do not cover pioneer invention, and. being thus limited in scope were not infringed by the structures used by the Government known as flying boats and SS-lL.u
    
    (2) Claims 12, 17, and 18 of said patent, directed to the arrangement of supporting and control surfaces, were not infringed by the said structures.
    
      (3) Olaims 9, 12, and 32 thereof, predicated, in addition to the foregoing, upon supporting surfaces curved parabolically, were likewise not infringed by the said structures.
    
      The Reporter’s statement of the case:
    
      Messrs. William R. Harr and Hervey 8. Knight for the plaintiffs. Mr. Charles H. Bates was on the brief.
    
      Mr. Thomas B. Booth, with whom was Mr. Assistant Attorney General Hermann J. Galloway, for the defendant. Messrs. Frederick L. Emery and Robert H. Young were on the briefs.
    The court made special findings of fact, as follows:
    I. On April 26, 1905, John J. Montgomery, a citizen of the United States, residing in the county of Santa Clara, State of California, filed an application for letters patent of the United States for improvements in aeroplanes; and on September 18, 1906, there was granted to the said Montgomery upon said application Letters Patent No. 831173, a copy of which is filed as Exhibit A to these findings.
    II. Said John J. Montgomery was the owner of said Letters Patent No. 831173 at the time of his death intestate October 31, 1911. He left as his heirs at law Regina Cleary Montgomery, his widow, and Ellen Montgomery, his mother. On January 5, 1912, his brother, Richard J. Montgomery, was appointed administrator of his estate by the Superior Court of the County of Santa Clara, California, qualified as such, and entered into and upon its administration.
    On February 18, 1914, said Ellen Montgomery sold, assigned, and transferred all her right, title, and interest in and to the estate of said John J. Montgomery, deceased, including said Letters Patent No. 831173, to said Richard J. Montgomery and his sisters, Mary C. Montgomery, Margaret H. Montgomery, and Jane E. Montgomery, plaintiffs herein.
    On April 10, 1914, the Superior Court of Santa Clara County, California, in the matter of the estate of said John J. Montgomery, deceased, entered a decree ordering the distribution to the plaintiffs herein of their respective shares in said Letters Patent 831173, to wit: One-half to Regina Cleary Montgomery and one-eighth each to Richard J. Montgomery, Mary C. Montgomery, Margaret H. Montgomery, and Jane E. Montgomery, whereby said plaintiffs thereupon became joint and exclusive owners of said letters patent.
    On July 27, 1914, said plaintiffs executed an instrument in writing with one Frank A. Garbutt, which instrument was as follows:
    “ Now, therefore, in consideration of the premises and in consideration of one dollar ($1.00) mutually in hand paid, it is agreed that in consideration of the assignment by the parties of the second part to the party of the first part of an undivided one-half (^) interest in and to the said Montgomery patent, said party of the first part will proceed to negotiate a combination between the various holders of patents in the United States who own aeroplane patents which are of value in the present condition.of the art, the patents particularly referred to being the Wright patents, the Cur-tiss patents, the Lamson patent, and the Montgomery patent; that these negotiations will look to an amicable and complete settlement of the differences existing between the parties hereto and the holders of adverse patents, to the end that the manufacture of aeroplanes will be encouraged and a free field will be offered for the development of the art, and that the Montgomery name will be given the prominence which it deserves by reason of the priority of the application of the principles of flight by the late Prof. Montgomery, and to the end that his heirs may receive their proportionate share of the benefits to be derived from the workings of his inventions.
    “ The party of the first part agrees to send a party or parties East at his own sole cost and expense to carry on these negotiations and to pay all expenses of same.
    • “ Failing in the successful prosecution of these negoi ia-tions, the party of the first part agrees to commence action or actions at law or to bring about the commencement of such action or actions at law or suit or suits in equity as in his judgment appear most advisable to accomplish the end desired and agrees to prosecute the same to a successful termination, or to the point where in his judgment he deems it inadvisable to proceed further, all such actions and suits to be at the sole cost and expense of the party of the first part.
    
      “The party of the first part agrees to employ all legal counsel which in his opinioir are or is necessary or desirable in carrying on the said litigation, and to pay all expenses incurred by him or at his instance or under his direction in connection with said litigation, and same shall not be a charge in any way upon the interests of the parties of the second part in said patent.
    “ Should the party of the first part determine in his judgment .that the chances of success in said litigation are not sufficient to warrant the further expenditure of time and money he shall then and in that event have the right to withdraw from this contract, first giving to the parties of the second part the privilege of carrying on said matters at their own expens'e, and should the party of the first part so withdraw from this contract, first giving to the parties of the second part and to reassign and transfer to them the said one-half (%) interest in said patent which has previously been transferred to him, on the repayment to the said party of the first part of the money which- he has expended under this contract up to date of his withdrawal.”
    In accordance with this instrument, two suits in equity for patent infringement were filed in California, the bill of complaint setting forth as coplaintiffs Richard J. Montgomery, Mary C. Montgomery, Margaret H. Montgomery, Jane E. Montgomery, and Frank A. Garbutt, the name of Regina C. Montgomery evidently being omitted through inadvertence.
    Subsequently, under date of March 27, 1917, the following notice was served on Garbutt through Alfred J. Cleary, the duly appointed attorney in fact of the Montgomerys:
    To Mr. Frank A. Garbutt,
    
      Los Angeles, California:
    
    You will please take notice that the undersigned parties, by their undersigned attorney in fact, hereby terminate and consider themselves no longer bound by the agreement entered into on the 27th day of July, 1914, or any of its terms, by and between yourself as party of the first part and the undersigned as parties of the second part.
    This action is taken because of your failure to perform the terms of said agreement and because of your failure to prosecute the suit for the enforcement of patent rights No. 831173, known as the Montgomery aeroplane patent, which patent rights were the subject matter of the above-mentioned agreement.
    Dated San Francisco, Mai’ch 27, 1917.
    (Signed) ' Regina Cleary Montgomery,
    Margaret H. Montgomery,
    Mary C. Montgomery,
    Jane E. Montgomery,
    Richard J. Montgomery.
    By Alfred J. Cleary,
    
      Attorney in fact.
    
    Receipt of the above notice is hereby acknowledged this -day of March, 1917.
    No offer was at that time made to reimburse Garbutt for any money spent in connection with or any of his activities under the above instrument.
    In a -suit filed in the Southern District of New York, September 22, 1917, against the Wright-Martin Aircraft Corporation, for infringement of the Montgomery patent 831173, with Regina Cleary Montgomery, Richard J. Montgomery, Mary C. Montgomery, Margaret H. Montgomery, and Jane E. Montgomery as complainants, Judge Hand held the instrument of July 27, 1914, to be an assignment by virtue of which Garbutt became the legal owner of a one-half undivided interest in the patent.
    An amended bill of complaint was then filed under date of October 22, 1919, by the same complainants, which amended bill made reference to a reassignment by Garbutt to the complainants in that cause, under date of August 18, 1919, in which Frank A. Garbutt sold, assigned, transferred, conveyed, and set over, remised, relinquished, and forever quit-claimed unto the plaintiffs herein each, every, and all of the several rights, titles-, and interests in and to said letters patent, which rights, titles, and interests were acquired by the said Garbutt from the said plaintiffs under and by virtue of the aforesaid agreement of July 27, 1914, together with any other right or interest in and to said letters patent of which the said Garbutt might be at the date of said reassignment, or ever have been possessed; and that the plaintiffs have, since said last-named reassignment, continuously been and now are the joint and exclusive owners of said letters patent.
    This reassignment, which is not before the court, appears to have been made by Garbutt upon receipt of $1,500 as reimbursement for expenses incurred under the prior agreement.
    The present action against the Government was filed September 22, 1917, or a little over two years prior to this reassignment.
    III. Montgomery’s first experiments on flight were begun about 1883 and continued until 1886. No laboratory or experimental records "appear to have been kept by Montgomery with respect to these or subsequent experiments.
    This early work was described on pages 248-249, of Progress in Flying Machines, by Chanute, published in 1894, from information obtained from Montgomery. The structures used are but vaguely described, and no basis is found in this book for the embodiments claimed in the patent in suit.
    The oral testimony with respect to the early work of Montgomery also fails to establish any basis for the structures claimed. *
    From 1886 to 1903 Montgomery’s inventive thought was turned to other investigations, and we find the following patents issued to him:
    Nov. 12, 1895, British patent No. 21477, petroleum burner and furnace.
    Nov. 12, 1895, German patent No. 88977, petroleum ofen.
    Nov. 12, 1895, U. S. patent No. 549679, petroleum burner (application filed June 25, 1895).
    Nov. 14, 1895, Canadian patent No. 50585, petroleum burner.
    Feb. 19, 1901, Canadian patent No. 70319, concentrator.
    July 23, 1901, U. S. patent No. 679155, concentrator (application filed June 6, 1900).
    Nov. 3,1903, U. S. patent No. 742889, concentrator (application filed Jan. 13, 1902.)
    In the early part of 1903 the interest of Montgomery was renewed by meeting a man named Baldwin, who was working on dirigible balloons. Correspondence began between Montgomery and Baldwin in June, 1903, and in a letter written by Baldwin under date of November 23rd the first reference to a model is made. In this letter Baldwin states:
    “ Should you want any aid in the construction of your moddle [sic] just let me know and it will be O. K. and considered personal.”
    Closely following this Montgomery wrote to his mother, under date of December 15, 1903, in part as follows:
    “ Saota Clara, Cal., Deo. 15th.
    
    “ Dear Ma : I have just returned from Mr. Leonard’s, where I performed a number of experiments with my little flying machine. I dropped it several times from a very'high bridge, and it would sail beautifully and glide around and light just like a bird. Once it descended sailing around and around several times just as you have seen birds do. But the poor little thing came to disaster, and now I am making another with small steel rods instead of wood, which I shall try by raising on a big kite so arranged that when it gets about 200 feet high it will be released and let drop. In this way it will be possible to have it descend without accident. In nearly every experiment I performed the. machine in sailing around would strike the timbers of the bridge or the side of a hill and break itself. Finally after making a beautiful flight it turned and came towards the foot of the bridge and sailed right into a culvert and tore itself to pieces. But in all the experiments it never turned over once. The Fathers who know about it are very enthusiastic. * * *”
    Montgomery entered into an agreement with Baldwin under date of April 28,1904, which agreement set forth in part that whereas Montgomery was the inventor of a certain flying machine, device, or contrivance for gliding and soaring through the air without the aid of gas, for the issuance of letters patent on which, when it was more fully developed and perfected and if it proved successful, he intended applying to the Government of the United States and of various foreign countries, and which said machine, device, or contrivance, if successful, would be known as the Montgomery air ship.
    The agreement also provided that:
    “ Both parties hereto agree that they will proceed with .all convenient and reasonable dispatch after this agreement is executed to make such trials or experiments as may be necessary to assure them that said flying machine, device, or contrivance may be successfully dropped from an ascended balloon, or from such other elevation or elevations as may be mutually fixed upon, and thence glide or soar safely to the earth, without the aid of gas, and would hence make a success for exhibition purposes; and, if said machine is not as yet sufficiently developed to answer the above requirement they agree that they will jointly proceed to develop it, so that, if possible, it may be made to answer the same; and both parties shall give to such experiments and to any such development work all of their time and attention necessary ; and all the costs and expenses of said experiments and development work shall, whether said experiments prove successful or otherwise, be paid and borne by the party of the second part, without any cost or expense to the party of the first part.”*
    Montgomery’s relationship with Baldwin is summarized in the letter to his brother of May 15,1904, which was in part as follows:
    “ Over a year ago there came to San Jose a celebrated balloonist and manufacturer of balloons, who made his fortune by perfecting and giving the first successful exhibition with the parachute. Accidentally he heard I had worked on flying machines. He came to see me and asked my ideas on the subject. I told him of the discoveries I had made. After a number of visits he finally told me he had been all over the world hunting for some definite idea on the subject and he said I was the first man he had met who had any definite idea regarding the laws. And he was so satisfied with my ideas that if I would put them in a practical form he would have machines made and he would test them himself. All that he wanted was a machine that he could drop safely from a balloon and which would glide gradually to the ground. With this he could give exhibitions as he did with the parachute, getting from one to three thousand dollars per week. I at first did not consider the prospect. But as he kept after me I concluded to do so. And fast Christmas I made some small models and went to the coast. There I dropped the models from a wire 100 ft. high stretched between two hills and they are perfect wonders. By a special pulley, etc., I could draw them up and let them fall, sometimes with and again without any weight. I let them loose in all possible positions, in an erect position, on their backs, from the head, then from the tail and from a tip of the w,ing, and in every instance they would turn like a cat, then come sailing down beautifully, it making no difference whether the wind was blowing or not.
    “ I gave him my report and he said these were perfection and now we are making a large one which he will try probably within the next two weeks. He says if the big machine will do half as well as the small ones we can clear over one hundred thousand dollars the first year. We have signed contracts and are working like beavers.
    “And just as soon as we are satisfied he will start out, as he has his balloons and all necessary machinery ready for the purpose. He has been all over the world giving exhibitions and is fully acquainted with all pertaining to the business.
    “ If this very promising plan is successful we will be very well fixed.”
    This documentary evidence shows that after a lapse of approximately seventeen years, during which Montgomery was occupied along other inventive lines, he renewed his experiments about December, 1903, under the impetus of this contract with Baldwin. It shows that a large apparatus was under construction May 15, 1904, but throws no light on the structure of any of the small models, or the large apparatus.
    The only physical exhibits offered which are alleged to have been in existence pr,ior to the filing date of the Montgomery application which matured into the patent in suit were a part of a small pink-silk wing and a fragmentary small tandem-wing model with figured-calico wings.
    These physical exhibits came into the possession of Jane Montgomery, a sister of the patentee, some t,ime in 1905. Their history is obscure and their dates of origin unknown and their original structure is unascertainable.
    There is no oral testimony regarding the structure of the 1903 models.
    The next landmark in Montgomery’s work was the testing of an aeroplane large enough to carry a man. This machine appears to have been assembled and tested at the ranch of Peter Cox in the summer of 1904, the tests comprising the suspension of the plane withi an operator from a line stretched between two poles. The plane was further tested by men running down a steep hill and pulling the plane by means of a rope with Montgomery riding in or holding onto the plane.
    These probable tests in the summer of 1904 and subsequent tests made ait the Leonard ranch in March, 1905, when a Montgomery aeroplane was cut loose from a hot-air balloon with an aeronaut named Maloney on board, as well as subsequent public tests, are immaterial in carrying back the date of invention of the patent in suit to an effective date with respect to the prior art.
    In the numerous examples of prior art cited by defendant, the latest date is that of July 1, 1904, the “ Delivre ” date or issue date of the French Wright patent No. 342188.
    No facts have been presented which show the date of invention as defined by the claims at issue of the patent in suit to be anterior to the effective dates of any of the prior art cited by defendant.
    IV. Plaintiffs charge construction and use by the United States of aeroplanes embodying the subject matter of the Montgomery patent in suit, and particularly of the following claims of said patent, to wit, claims 4, 9, 12, 16, II, 18, 28, and 32.
    V. It has been agreed by the parties to this suit that the two machines known, respectively, as the JN-.l¡.H and H8-1L flying boat are illustrated by the plans and specifications furnished plaintiffs by defendant, and in,evidence in this case as plaintiffs’ Exhibits Nos. 114 and 115, and that said machines were in use by the United States at the time (September 22, 1911) plaintiffs’ petition herein was filed.
    It has also been stipulated and agreed by the parties hereto that “ evidence, as to the extent of the alleged use or manufacture by or on behalf of the United States of said invention, be reserved until the court shall have determined the questions of validity and use of patent No. 831173.”
    VI. The object of the patent in suit is stated to be the provision of a controllable aeroplane device.
    The illustrated embodiment discloses a structure having two wings or aeroplanes A and B alike in shape or contour and extent of supporting surface, and arranged ,in tandem upon a supporting framework.
    
      The wing surfaces are curved fore and aft in transverse section and ,the best form of curvature is stated to be that of a parabola.
    The wings in a fore and aft direction are given an increasing upward tilt toward the tips, producing a sinuosity in the shape of each wing. To offset the increased resistance of the more abruptly inclining outer portions, the outer portion of each wing has the front end of the ribs cut or trimmed away by an increasing amount as the outer portions of the wings are approached. The sections near the ends are therefore less sharply curved at ,their front ends than the forward ends of the sections nearer the center.
    The rear wing is not capable of being adjusted so as to have a negative angle of incidence with respect to the front wing.
    Numerous of the claims specifically call for a parabolically curved surface, while others are directed broadly to a curved wing or surface.
    The patentee also states the following with respect to wing surfaces:
    “ Investigation has shown me that a wing is a specially formed surface placed in such a position as to develop a rotary movement in the surrounding air. This position is determined by mathematical considerations.”
    Mathematically defined, a parabola is a curve produced by the intersection of a cone with a plane parallel to its side, and it is represented by the formula y — 2px.
    The embodiment of the invention described and illustrated is without power and is intended to function under the impetus of gravity.
    One of the control features described and claimed pertains to a change in curvature of the wings. Each supporting-wing is provided near its rear edges with oppositely extending transverse arms or spars, hinged at a middle point. Each spar is capable of a free swinging movement, up or down about a fulcrum provided by the underlying longitudinal frame bars.
    Each spar has fastened to it a series of wires which are in turn connected to a foot bar by means of which the operator is to manipulate the wires, and to draw down the rear portions of the wings against the upward pressure of the air, or to allow them to r,ise under the air pressure. This adjustment or alteration in the form of the wing surfaces, permitted by the flexibility of the wings and ribs, is termed in the claims a change in “ curvature.”
    This control is described as follows in the patent: “ By pressing down on the stirrup bar on one side the rear portions of the wing surfaces on one side are drawn down while those on the opposite side are allowed to yield to the air pressure beneath. By these means the wing surfaces change their form.”
    The drawings of the illustrated embodiment show a connection of the control cords contrary to this description and which would result in an inoperative structure if followed. In Fig. 6 the control cords from the rear edges of the front wings are shown as crossed. The specification also describes them as crossed. By reason of this, depressing the right-hand end of the stirrup bar will cause the drawing down of the rear of the left front wing. In Fig. 7 the control cords from the rear wings are shown uncrossed. Depressing the right-hand end of the stirrup bar would, therefore, draw down the rear of the right rear wing.
    The description pertaining to Fig. 6 states that the cords are crossed; that referring to Fig. 7 merely states that the cords are guided “ downwardly and backwardly.”
    The angle of one wing may also be varied with respect to the other wing. This is done by manipulating a cord which serves to simultaneously actuate all the control wires for both sides of the rear wing, thereby drawing or curving down the entire rear portion of the rear wing against the underlying pressure of the air, or allowing it to rise under the air pressure.
    This control is for the purpose of meeting the requirements of varying speeds of motion.
    For longitudinal control of the structure of the patent a large horizontal tail surface or rudder C is hinged directly to the rear of the rear wing B and is adapted to be swung vertically- by means of a control cord. This tail surface is said to be but an extension of the rear wing surface.
    
      Fixed to the horizontal tail or rudder is a large vertical fin or rudder H. This is incapable of any side movement such as that possessed by a rudder. It is fixed to and extends above and below the tail and moves up and down as the latter is swung about its hinge.
    The horizontal tail provides for the longitudinal or up-and-down control, and the vertical fin, acting in conjunction with the adjustment of the wings (changing their curvature), provides for lateral control and steering to the right and left.
    The operator sits astride the lower frame bar between the wings, which have a substantial space or gap between them, and places his feet on the stirrup bar.
    No instructions as to the proper use or manipulation of the controls are found in the specification of the patent in suit.
    In the application which materialized into the patent in suit the adjustment of the wings was originally referred to as producing a change of form of the wing surface or a change of surface.
    On the first action by the Patent Office, claims 1, 2, 3, 4,17, and 24, including as an element the said means for changing the surface of the aeroplane, were rejected on the prior art, which included patents to Boswell, 728844, May 26, 1903, and Beeson, 376937, of 1888. The applicant, in response to this rejection, amended under date of November 16, 1905, all of said claims which had been rejected on the prior art by incorporating in them phraseology to specifically designate the adjustment as effecting a change in curvature.
    At the time of the said amendment, under the heading of “ Eemarks,” there was submitted by the applicant the following statement :
    “ The essential distinction of this aeroplane, with respect to its capability of change of ¡surface, is that such change is effected and lies wholly within its own integral borders, by a change in its own curvature, in contradistinction to a general angular change such as results from the relative movement of a sectional attachment like the hinged tail of the reference.”
    VII. In the two machines known, respectively, as the JN-IJI and R/S-1L, hereinafter referred to as the Government machines, the wings are superposed one above the other; in one of the machines, the JN-J/.H, the wings are staggered, with the top one slightly in advance of the lower. The wings are of varying thickness at different points along their chord, so that the upper and lower surfaces have different curvatures, with a decreasing curvature from front to rear.
    The wing design or curve used in the JN-4-H, hereinafter referred to as the Army machine, is known as the Eiffel 36, and was determined experimentally by a French engineer named Eiffel.
    The wing design or curve of the SS-1L, hereinafter referred to as the Navy machine, is that known a,s RAF6, which was developed in Great Britain.
    It has not been proved that these empirical wing curves are parabolic.
    The wings of the Government machines, are rigid in structure, having hinged sectional surfaces at the rear edges of the wings. These surfaces, technically designated as ailerons, are capable of being given an angular change of position with respect to the wing surface. The Government machines do not simultaneously depress the ailerons at opposite sides of the wing, but provide for the depression of the aileron, or ailerons, at one side of the wing simultaneously with the reverse movement, or elevation, of the aileron, or ailerons, at the opposite pide of the wings.
    This movement of the ailerons is employed for balancing the machines, and the ailerons are also used in combination with a movable vertical rudder at the rear for making turns. It is possible to turn a machine to the right or left by the use of the ailerons alone, but such maneuver is contrary to conventional practice, which comprises the joint use of the vertical rudder and ailerons for turning.
    The Government machines have a fixed vertical fin at the rear of the fuselage which is for the purpose of directional stability.
    The Government machines have a horizontal stabilizing surface of relatively small area (about 10% of the wing surface) located at the rear of the fuselage. This is braced against both positive and negative loads and is fixed at a negative angle relative to the supporting wings, thus receiving no load in normal flight and therefore not functioning under normal conditions a£ a supporting surface.
    In the Government machines the wings have no sinuosity, and the curvature of the front ends of all the fore and aft cross ribs is substantially the same. The only part of the wing where the front of the fore and aft wing section is less sharply curved than the front of sections nearer the center is beyond the outer rib of the wing in the extreme, small, triangular tip portion.
    The Government machines are provided with motors and propellers for propulsion through the air. The motor may be shut off, however, when the machines are in the air, and the machines may then be operated or controlled while descending under the impetus of gravity.
    VIII. At the time said Montgomery devised his alleged improvements, set forth in the said claims at igsue in this suit, the following letters patent were in and a part of the prior art and, as shown by the file wrapper of the said patent in suit, were referred to by the Patent Office Examiner in passing on the application for said patent, and are, by reference, made a part of this finding of fact;
    
      
    
    IX. In addition to the letters patent referred to in the file wrapper of the Montgomery patent in suit, the following letters patent were also in, and a part of, the prior art at the time said Montgomery devised the said alleged improvements, and are, by reference, made a part of this finding of fact:
    
      
      
    
    X. In addition to the aforesaid letters patent, the following publications were in, and a part of, the prior art at the time said Montgomery devised the said alleged improvements, and are by reference made a part of this finding of fact:
    Deft.’s Ex. No.
    L’Aeronaute, published at Paris, January, 1872, pages 2 to 9, inclusive, article by A. Penaud entitled “Aeroplane Auto-moteur ”_ 72
    La Locomotion Aerienne, by A. Goupil, published at Charleville, Prance, in 1884, pages 101, 103, 104, and Plates VI and VII— 73
    Twenty-third Report of the Aeronautical Society of Great Britain, published at Greenwich, England, in 1888, pages 65 to 69, inclusive, article by Horatio Phillips_ 74
    Der Vogelflug ais Grundlage der Miegekunst, by Otto Lilienthal, published at Berlin, in 1889, pages 70 to 102, inclusive, pages 136 to 154, inclusive, pages 177 to 182, inclusive, and Plates I to VIII, inclusive_ 75
    Experiments in Aerodynamics, by S. P. Langley, published at Washington in 1891, pages 26 to 47, inclusive, and 105 to 108, inclusive_ 77
    Revue de L’Aeronautique, published at Paris in 1893, pages 69 to 99, inclusive, and Plates XII to XV, inclusive, article by M. O. Ader entitled “L’Aeroplane ‘Eole’”_ 110
    Scientific American Supplement published at New York, June 3, 1893, pages 14, 258, and 14, 259, article entitled “ Phillips’ Flying Machine”_j._ 78
    Proceedings of the International Conference on Aerial Navigation, published at New York in 1894, pages 11 and 21 to 38, inclusive, 81 to 83, inclusive, 253 to 264, inclusive, and 273 to 287, inclusive, containing, respectively, papers by C. W. Hastings, S. P. Langley, W. Kress, and A. F. Zahm_ 79
    
      Deft’s Ex. No.
    The Aeronautical Annual for the years 1895, 1896, and 1897, published at Boston, Mass., in the respective years named— 80
    McClure’s Magazine for June, 1897, published at New York City, June, 1897, pages 647 to 660, inclusive, article by S. P. Langley entitled “ The ‘ Plying Machine ’ ”- 81
    Journal of the Western Society of Engineers, published at Chicago, Ill., October, 1897, Vol. II, No. 5, pages 593 to 628, inclusive, article by Octave Chanute, entitled “ Gliding Experiments ”-„- 82
    McClure’s Magazine for June, 1900, published at New York City, June, I960, pages 127 to 133, inclusive, article by O. Chanute, entitled “ Experiments in Flying ”_'_ 83
    Annual Report of the Board of Regents of the Smithsonian Institution for the year ending June 30, 1900, published at Washington in 1901, pages 197 to 216, inclusive, article entitled “ The Langley Aerodrome ”_ 84
    Scientific American, Volume LXXXIV, No. 9', published at New York City, March 2, 1901, page 137, article entitled “ The . Kress Aeroplane ”- 85
    Journal of the Western Society of Engineers, Vol. VI, No. 6, published at Chicago, Ill., December, 1901, pages 489 to 510, inclusive, article by Wilbur Wright enti'.led “ Some Aeronautical Experiments ”_ 31
    Flying, No. 2, published at London, March, 1902, pages 53 to 60, inclusive, article by Sidney H. Hollands entitled “ Motor Aviation of To-day and of Recent Years”- 86
    Illustrirte Zeitung, published at Berlin, March 5, 1903, page 351, illustrated article on flights of the Wright brothers_ 87
    La Locomotion, published at Paris, April 11, 1903, pages 225 to 227, inclusive, illustrated article on flights of the Wright brothers entitled “ M. Chanute a Paris ”- 88
    L’Aerophile, published at Paris, April, 1903, pages 81 to 86, inclusive, illustrated article on the flights of the Wright brothers entitled “ Dinner Conference du 2 Avril, 1903 ”_ 104
    L’Aerophile, published at Paris, August, 1903, pages 171 to 183, inclusive, article entitled “ La Navigation Aerienne aux Etats-Unis,” by Chanute_ 34
    Wiener Luftschiffer-Zeitung, published at Vienna in August, 1903, pages 173 and 174_ 89
    Journal of the Western Society of Engineers, published at Chicago, Ill., in August, 1903, containing an address by Wilbur Wright entitled “Experiments and Observations in Soaring Flight ”_ 30
    Scientific American, Vol. LXXXIX, No. 16, published at New York City, Oct. 17, 1903, page 272, illustrated article on the Langley machine- 90
    
      Deft.’s Ex. No.
    American Inventor, Vol. IX, No. 9, published at Washington, Nov. 1, 1903, pages 208/and 209, illustrated article entitled “ The Langley Flying Machine”_ 91
    Revue Generate des Sciences, published at Paris, November 30, 1903, pages 1133 to 1142, inclusive, illustrated article by O. Ohanute entitled “ L’Aviation en Amerique ”_ 92
    And
    Progress in Plying Machines, by Ohanute, published at New York Oity in 1894, plaintiffs’ Exhibit No. 79.
    XI. At the time Montgomery devised his alleged improvements, set forth in the patent in suit in the aforesaid claims at issue, the following structures were in, and a part of, the prior art:
    1. Aeroplane glider, constructed in the United States by the Wright brothers and put into use at Kitty Hawk, North Carolina, in 1900.
    2. Aeroplane glider, constructed' in the United States by the Wright brothers and put into use at Kitty Hawk, North Carolina, in 1901.
    3. Aeroplane glider, constructed in the United States by the Wright brothers and put into use at Kitty Hawk, North Carolina, in 1902.
    4. The Wright glider of 1902, as altered and put into use at Kitty Hawk, North Carolina, in the summer of the same year.
    5. The motor-driven flying machine of 1903, constructed in the United States by the Wright brothers and put into use at Kitty Hawk, North Carolina, on December 17, 1903.
    The court decided that plaintiffs were not entitled to recover.
   Booth, Chief Justice,

delivered the opinion of the court:

This is a patent case. The petition alleges that under the act of June 25, 1910, 36 Stat. 851, plaintiffs are entitled to recover for an infringement by the Government of claims 4, 9, 12, 16, 17, 18, 28, and 32 of Letters Patent #831173 granted on September 18, 1906, to John J. Montgomery, now deceased. The Government denies infringement and challenges the validity of the patent.

A preliminary question of title is called to our attention. On July 27, 1914, the plaintiffs assigned an undivided interest in the patent to Frank A. Garbutt. The consideration for the assignment was a duty imposed upon Garbutt to attempt to reconcile the conflicting claims of Montgomery with other inventors in the same art and procure for the Montgomery patent a sufficient recognition to entitle the owners of the patent to realize its worth in money; failing in this, to institute suits for infringement of the patent. Garbutt did commence two suits, both were dismissed without prosecution to a conclusion, and subsequently, i. e., after this suit was commenced, Garbutt reassigned his interest in the patent to the plaintiffs. We think in view of the result of this suit that the contention of the defendant is unimportant.

The petition alleges infringement of claims 4, 9,12, 16, 17, 18, 28, and 32 of Montgomery’s patent. There are forty-six claims in the Montgomery patent.

The plaintiff’s case is predicated largely upon a contention that Montgomery, the patentee, was a pioneer in the art and his patent a basic patent; that he was the first to invent the principle of wing warping to secure equilibrium and lateral control essential to flying; that the other elements of his machine disclose the principles of stability and rudder control, all of which, or their equivalents, are embodied in the Government machines, offered as exhibits of infringing devices. The record in the case is moat voluminous and involved and has required exacting attention and labor. The first vital issue depends upon whether from the record it is to be held that Montgomery was a pioneer inventor and his device a basic patent. If so, his cl'aims, as repeatedly adjudicated, are to be accorded a broader construction than were the situation otherwise. Unless it may be said and established by proof that the inventor has a patent which performs a function which was not performed before, he is not entitled to be designated a pioneer inventor. Westinghouse v. Boyden Power Brake Co., 170 U. S. 537.

Attempts to construct flying machines did not, of course, originate with Montgomery. The art is old, its progress was slow, the early development crude and impracticable. Inventors many decades ago studied the flight of winged animals and sought without -success to imitate their motions and bring into being a device that would accomplish, with the aid of man, what flying birds, eagles, vultures, etc., did with natural ease. This record is replete with a l'arge number of exhibits, publications, and patents which antedate Montgomery by years, disclosing the extent of sustained interest in the art, and efforts made to accomplish flying in a heavier-than-air machine.

Montgomery first centered his attention upon the subject in 1888; from this date until 1886 he conducted a number of experiments with some sort of a mechanism designed as a “ glider.” He does not seem, at this time at least, to have conceived the idea of soaring from the ground and remaining aloft in a device under control. What he was attempting was the construction of a machine that might be released from high altitudes and glide safely to earth under control. From 1886 until 1908 Montgomery turned his attention to other and distinct inventive fields; he contributed nothing to this particular art during this period- In 1903 he renewed his experiments. During that year he came in contact with one Baldwin, a balloonist, who had been making successful glides from a hot-air balloon in a parachute. Baldwin became interested in Montgomery’s efforts and the two entered into a contract, whereby Montgomery was to construct his device, and if it proved successful in descending from a balloon with a man on board the two were to engage in public exhibitions and divide the profits. Montgomery and Baldwin disagreed before any actual experimentation with the prospective glider obtained, and Montgomery thereafter entered into a somewhat similar contract with another balloonist. Montgomery had constructed in May, 1904, a large machine to meet the requirements of the Baldwin contract, and in the summer of 1904 carried on some experiments at the ranch of Peter Cox, in California. The exact and detail structure of his machine is not disclosed. The experiments made consisted in elevating the machine to a desired height by suspending it from a wire to which it was attached, stretched between two upright poles. At the proper time it was released to ascertain its gliding qualities. Other tests were made by resorting to a steep hill, when men, by means of a rope, pulled it down the incline, Montgomery holding onto the device. Just how many and the exact character of the tests so made is impossible of determination. It is sufficient to observe that they were quite numerous. In March, 1905, Montgomery attached his machine to a hot-air balloon, and having secured the services of an aeronaut by the name of Maloney to make the test the machine with Maloney in the saddle seat was released from the balloon at a high altitude and safely glided to earth. On July 8, 1905, Maloney attempting the same experiment lost his life, the machine failing to function.

On April 26, 1905, Montgomery filed his application for the patent in suit. The patent was granted on September 18, 1906.

We have epitomized Montgomery’s early efforts, with respect to which a great volume of proof has been adduced, solely because the plaintiffs have sedulously insisted that the facts are sufficient to antedate the effective date of invention to a time which would exclude reference to certain prior art. A careful analysis of the record upon this point is conclusively convincing that the proof signally fails to sustain the contention. Out of fifty-two prior patents and publications cited in the record all but eight bear dates which make them statutory bars, provided they disclose the structure of the patent in suit. The courts have uniformly held that to show anticipation as against issued letters patent some drawing, some model, some positive means of identification must appear. Oral testimony is regarded as insufficient and unreliable for this purpose. Without exception it is to be discarded, for, however free from intentional misrepresentation, it is uniformly tinctured with the interest of the parties in the litigation and necessarily characterized with acute limitations of the possibility of particular and precise descriptions of the device and its comparison with another. Symington Co. v. National Malleable Castings Co., 250 U. S. 383; Deering v. Winona Harvester Works, 155 U. S. 286; The Barbed Wire Patent, 143 U. S. 275; Torrey v. Hancock, 184 Fed. 61; Emerson & Norris Co. v. Simpson Bros. Corp., 202 Fed. 747.

The flight of April 29, 1905, took place three days after Montgomery’s application for a patent was filed, and is available solely as proof on the point of operativeness.

It is impossible from the record to abstract with any degree of accuracy the detail structure of Montgomery’s early machines. He preserved no data, kept no record of measurements, and left no reliable information from which a court or one skilled in the art might profit from what he did, or ascertain the means he employed to do it. At best, the evidence is probative on the single point that the patentee did on the dates stated do the things described, and discloses only the happening of the chronicled events. True, Chanute in 1894, in his book Progress in Flying Machines, devotes an article to Montgomery’s experiments, in which he outlines in general terms the Montgomery machines, from which one may abstract a conception of general lines of construction; however, it is clear from what was therein said, and the results of the tests described, that it would be hazardous indeed to ascribe to Montgomery a distinct conception at this time of those fundamental principles of aerodynamics, which finally culminated in the invention of the airplanes which it is now claimed infringe the patent in suit. If, however, Chanute’s article did disclose the specific features of Montgomery’s device, then the article itself stands as a statutory bar to the validity of the patent. Montgomery’s articles and addresses printed in the record found publication years after his application for the present patent had been filed and granted, and are purely eto post facto.

There are 46 claims in the Montgomery patent. Infringement is alleged as to claims 4, 9, 12, 16, 17, 18, 28, and 82. The device claimed is manifestly a combination of elements designed to function in certain ways. Fig. 1 of the patent illustrates a side elevation of the patented machine. We reproduce it from the letters patent:

To fly in a heavier-than-air machine, one capable of bearing aloft a man, exacted the creation of a device that would function in a variety of ways. First, it must be capable of soaring from the ground. Second, equilibrium when aloft was indispensable. Third, directional control was equally essential. Fourth, stability must be accomplished, and finally, the means to descend when desired was no less important. Soaring, equilibrium, control, and gliding were concededly indispensable. Noted scientists from an early date discovered the above requisites if a successful flying machine was to materialize. The difficulties encountered were not so much in the discovery and recognition of the principles involved, although tedious and prolonged, as in the means available to apply them in a practical manner.

The claims of the Montgomery patent which disclose the invention we think may be grouped. First, those which are directed toward the accomplishment of equilibrium and lateral control, dealing especially with a change in wing curvature to accomplish the purpose. This group, we think, comprehends claims 4, 16, and 28. Claim 16 being typical and most comprehensive of the group we quote it at this po,int:

“A curved aeroplane with means for changing its curvature, and a horizontal tail behind, which means for swinging it vertically.”

The second group may be said to be directed to the relative arrangement of the supporting and control surfaces, and would include claims 12, IT, and 18. Claim 17 we regard as typical of this group and therefore quote it:

“ In an aeroplane device, plural curved aeroplanes one in .advance of another, and a horizontal tail-surface behind the last aeroplane with means for swinging said tail-surface vertically.”

The third group is made up of certain claims which, in addition to the foregoing, are predicated upon or limited to a specific type or character of supporting surfaces, defined in the claims as “ curved parabolically.” In this group we place claims 9, 12, and 82. Claim 9 we regard as typical and quote it:

“An aeroplane curved parabolically from front to rear, its front portion being rigid, and its rear portion adjustable, with means for adjusting said rear portion relatively to the front portion, to change the surface of the aeroplane.”

Originality and novelty ascribed to the first group reside in the alleged fact that the claims disclose a form of construction whereby through a change in the curvature of the wings, integral w.ith the wing surfaces, equilibrium and lateral control of the machine in flight are secured. Wing surfaces on planes enable the airplane to soar; they furnish, through the reaction of air currents, the “ lift ” and support; when once aloft they function to maintain equilibrium and lateral control, the vital necessity for which is obvious. If the operator desires to turn in either direction, or the lateral equilibrium of his plane is disturbed, he may accomplish the former and retake the latter by a process of change in the wing surface. Montgomery, securing the front portion of h,is wings rigidly and • unmovable to his structure, so adjusted the rear portion relatively to the front portions as to change the surface of his wings by a change in their curvature. He did, by the application of a control device, make it possible to lower one side of the rear portion of his wings, which at the same time functioned to permit the other side of the rear portion to rise and thereby evolved this principle of wing warping. This was accomplished without changing angularly the wing surface, and the claimed novelty resides in making the change of curvature integral w,ith the wings themselves, i. e., the wing itself responded to the movement without the introduction of hinged ailerons. The result was a change in the rear cambered sections of the wings and offered to air currents the essential characteristics of an increased lift upon one side of the plane and a decreased lift on the other, enabling the airplane to turn in either direction.

Montgomery was not the first to recognize or avail himself of the principle of changing the form of wing surface to attain the desired results. On the contrary, he encountered at the outset of his application for a patent two prior patents embodying the conception and was compelled to limit his claims to avo.id the patented structures. Beeson on January 24, 1888, secured a patent for a structure illus-irated by the following device:

Beeson relied upon a curvel plane, to the rear portion of which he hinged an elongated element functioning upwards and downwards, which manifestly served to angularly vary the surface of his wing.

Boswell’s patent, illustrated by his Fig. 1, which we reproduce, disclosed a conception of the structure embodied in certain of Montgomery’s claims as filed. Boswell’s structure also obtained ah angular change in wing surface.

The Commissioner of Patents rejected the patentee’s claims 1, 2, 8, 4, 17, and 24 upon the patents cited above. Montgomery submitted amendments in answer to the rejections, in which he said:

“ The essential distinction of this aeroplane with respect to its capability of changing surface, is that such change is effected and lies wholly within its own integral borders, by a change in its own curvature, in contradistinction to a general angular change such as results from the relative movement of a sectional attachment like the hinged tail of the reference.”

We need not indulge citation to disclose the legal effect of this proceeding.

From the Revue de l’Aéronautique, vol. 4, published at Paris in 1893, we cite the following quotation:

“ It is known that the characteristic of a spiral is to turn about a center from which it is always receding and (fig. 27) that all tangents, at no matter what point of the curve, form similar angles with the radius; it is thus possible to trace spirals of greater or less curvature.
“This curvature is indispensable to a moving surface to enable it to obtain the maximum support in the air. It is also applicable and indispensable to individual feathers and to the propeller blades.
“It may be termed the universal sustentation curve of flight and support in the air.
“ The arching, as regards the degree of curvature of the concavity of the wings, will vary according to the speeds and loads, but without ever losing the character of a spiral. For all wings, without exception, small or large, the central or starting point C of the spiral curve coincides with the front of the wing; the Figures 26 and 27, representing two absolutely similar spirals, afford an example of this. On that of Fig. 26 is seen a full line which shows the shape of a large wing; on Fig. 27 the full line represents another wing, but much smaller. The horizontal lines H indicate the direction of translation. The same wing may change its degree of curvature during flight, but it will be only a modification of the spiral.
“ II. Laws common to all wings
“All wings, of whatever shape and nature they be, must obey the same laws. It can not be otherwise, because the difficulties of locomotion in the atmosphere especially when the latter is' disturbed, and the manoeuvres of starting from and' landing on the ground will be the same for all .aerial machines. Aeroplanes will also inevitably undergo great changes in their weight through the consumption of fuel or by being lightened if they let fall any part of their load to the earth.
“ From all this arises the necessity of being able to guide or to retard or' accelerate the speed of translation. And to be able to attain this end it is necessary that the wings should be capable of making four principal movements during flight:
“ 1. To be moved forwards or backwards in their entirety.
“ 2. To be folded up, so as to diminish or extend their surface.
“ 3. To be warped.
“ 4. To vary at will the curvature of the universal curve.
“All the combinations of frameworks, of articulations, of tendons and membranes are made with this end in view.
“ Because of the great difficulties which accompany the question of speed, we have been obliged to make wings for slow speed and high speed machines.”

Lilienthal in 1895 demonstrates in his Letters Patent #544816 a distinct conception of the value and functioning of curved wings in a flying machine.

Lilienthal was a distinguished engineer and scientist; he successfully accomplished thousands of glides, gave to the art publication of his experiments, and is prominently recognized by more than one outstanding scientist as contributing to the art most vital and necessary principles of the way in which air currents may be utilized in flying machines.

On May 26, 1906, Orville Wright and Wilbur Wright, of Dayton, Ohio, received their patent #821393. The two Wrights first became interested in aviation in 1896. They were close students of the science, and early in their careers became convinced that • equilibrium and control were the vital factors to be obtained if a heavier-than-air machine was ever to materialize. To this end they devised in July, 1899, a method of twisting or warping wing surface. A model was constructed along this line, a model clearly disclosing the conception of shifting one wing surface forward or back relatively to the other, and warping them by the same movement. This model was tested and responded satisfactorily. In 1900 the Wrights constructed a man-carrying model and it was tested at Kitty Hawk, North Carolina, in September and October, 1900. This particular machine, a glider, speaking now of wing surfaces, was so constructed that adjustments connecting the wings by flexible joints with upright posts, enabled the operator, “ lying prone in a cradle,” to actuate a wing warping effect by the sidewise movement of his body. The machine was flown a number of times with an operator on board during some of the flights, and without one at other times. It is true that the wing warping was accompanied by changing the relative position of the wings in flight, and not in the precise manner the patent in suit at a later point of time disclosed; but the demonstration of the effectiveness of the principle was firmly established. Lateral control and equilibrium were obtained for the first time effectively, leaving open to subsequent inventors the solution of a better method, if possible, to obtain the identical result. The Wrights, so far as the record herein is concerned, were the first to construct a device which sue-cessfully functioned in the desired way. The Wrights were assiduous in experimentation. In July, 1901, at Kitty Hawk tests of a larger machine were made in the presence of a number of persons, including one very distinguished scientist. These tests involved a number of flights, and many of them were decidedly successful. Without recounting in detail the number of tests made by the Wrights, and the success which followed their scientific and laborious investigation of the art, it is sufficient to state that on December 17, 1903, the Wrights demonstrated the possibility of successful flying in a heavier-than-air machine, motor driven, carrying and subject to the control of a living operator. This machine soared from the ground, demonstrated the possibility of control in sustained flight, and glided safely to earth in response to the operator’s desire. The significance of the Wright invention is disclosed by the following figure reproduced from the Wright patent:

Among the specifications accompanying the Wright patent are the following ones applicable in part to wing warping:

“A hem is formed at the rear edge of the cloth to receive a wire 7, which is connected to the ends of the rear spar and supported by the rearwardly extending ends of the longitudinal ribs 5, thus forming a rearwardly extending flap or portion of ,the aeroplane. This construction of the aeroplane^ gives a surface which has very great strength to withstand lateral and longitudinal strains, at the same time being capable of being bent or twisted in the manner hereinafter described.
“ When .two aeroplanes are employed, as in the construction illustrated, they are connected together by upright standards 8. These standards are substantially rigid, being preferably constructed of wood and of equal length, equally spaced along the front and rear edges of .the aeroplane, to which they are connected at their top and bottom ends by hinged joints or universal joints of any suitable description. * * * It will be seen that this construction forms a truss system which gives the whole machine great transverse rigidity and strength, while at the same time the jointed connections of the parts permit the aeroplanes to be bent or twisted in the manner which we will now proceed to describe. * * *
“ The part of the rope 15 under tension exercises a downward pull upon the rear upper corner d of the structure and an upward pull upon the front lower corner e, as indicated by the arrows. This causes the corner d ,to move downward and the corner e to move upward. As the corner e moves upward it carries the corner a upward with it, since the intermediate standard 8 is substantially rigid and maintains an equal distance between the corners a and e at all times. Similarly, the standard 8, connecting the corners d and A, causes the corner A to move downward in unison with the coimer d. Since the corner a thus moves upward and the corner A moves downward, that portion of the rope 19 connected to the corner a will be pulled upward through the pulley 20 at the corner. A, and the pull thus exerted on the rope 19 will pull the corner b on the other side of the machine downward and at the same time pull the corner g at said o.ther side of the machine upward. This results in a downward movement of the corner b and an upward movement of the corner o. Thus it results from a lateral movement of the cradle 18 to the right in Fig. 1 that the lateral margins a d and e A at one side of the machine are moved from their normal positions in which they lie in the normal planes of their respective aeroplanes, into angular relations with said normal planes, each lateral margin on this side of the machine being raised above said normal plane at its forward end and depressed below said normal plane at its rear end, said lateral margins being thus inclined upward and forward. At the same time a reverse inclination is imparted to the lateral margins b c and f g at the other side of the machine, their inclination being downward and forward. These positions are indicated in dotted lines in Fig. 1 of the drawings. A movement of the cradle 18 in the opposite direction from its normal position will reverse the angular inclination of the lateral margins of the aeroplanes in an obvious manner. By reason of this construction it will be seen that with the particular mode of construction now under consideration it is possible to move the forward corner of the lateral edges of the aeroplane on one side of the machine either above or below the normal planes of the aero-planes, a reverse movement of the forward corners of the lateral margins on the other side of ;the machine occurring simultaneously. During this operation each aeroplane is twisted or distorted around a line extending centrally across the same from the middle of one lateral margin to the middle of the other lateral margin, the twist due to the moving of the lateral margins to different angles extending across each aeroplane from side to side, so that each aeroplane surface is given a helicoidal warp or twist.”

The claims of the patent, 18 in number,- disclose clearly the structure specified. Beyond dispute is the established fact from evidence of not only oral witnesses but many written documents that the Wrights did embody in their aeroplane a complete conception of and means for imparting to the rear portions of an aeroplane wing a change therein which was intended to and did function to “ present to the atmosphere different angles of incidence,” and “ were capable of being moved to different angles relatively to the normal plane of the body of the aeroplane.”

In view of the extent of the prior art evidenced by granted patents and the innumerable publications part of the prior art, a subject much too voluminous to discuss in detail, it seems to us idle to contend that Montgomery was a pioneer in this particular field. A change in the surface of aeroplane wings, a change of curvature to effect equilibrium and control in flight, were among the very first principles recognized by a long list of preceding inventors and scientists, many of whom gave to ,the art the benefit of thousands of experiments and disclosed most valuable data long before Montgomery invented his device. The necessity for a curved wing surface and means of changing the same is illustrated in more than one patent, the inventors clearly conceiving the importance of this form of construction ,to obtain the reactions of air currents.

If more is needed to preclude the allowance of a broad construction of the patentee’s claim, we think it is to be emphatically found in an article published in McClure’s Magazine in June, 1897, by Professor S. P. Langley. This article contains not only a disclosure of wing construction as embodied in Langley’s experimental devices, but exhibits by various photographs a completed device resembling closely the patent in suit, i. e., two wing surfaces, mounted in tandem fashion upon a long steel supporting rod, each slightly curved, at the rear of which appears a rudder adapted both for vertical and horizontal steering, a concrete demonstration of the fact of not only the prior existence of a flying device constructed in form and fashion as the patentee constructed his device, but following in the footsteps of practically all prior inventors in the use of curved wing surfaces.

Montgomery’s patented device was not received commercially ; none of his machines were ever sold or met with any public demand. The patent was never put to any practical use, and, so far as the record discloses, inventors active in the art as well as the public generally did not accord the machine that full measure of inventive recognition usually attendant upon a pioneer patent. The courts have uniformly taken into consideration; in the construction of claims for which basic invention is claimed, the question of the general and practical utility of the device asserted to be pioneer in character. The Supreme Court in the case of Deering v. Winona Harvester Works, 155 U. S. 286, 295, used this language: “ If Olin had been the first to devise a contrivance of this description for adjusting the flow of grain upon the main elevator, it is possible that, under the cases of Ives v. Hamilton, 92 U. S. 426, and Hoyt v. Horne, 145 U. S. 302, a construction broad enough to include defendant’s device might have been sustained. But in view not only of the prior devices, but of the fact that his invention was of doubtful utility and never went into practical use, the construction claimed would operate rather to the discouragement than the promotion of inventive talent. Not only does it appear that the device described in this patent did not go into general use, but that the mechanism set forth in the patent to Bullock & Appleby of October 31, 1882, under which the defendants manufactured their machines, was extensively sold throughout the country for about eight years before any assertion of adverse right under the Olin patent.” To the same effect are the following cases: Boston Woven Hose & Rubber Co. v. Pennsylvania, Rubber Co., 164 Fed. 557; Henry v. City of Los Angeles, 255 Fed. 769, 780.

The sequential history of the art circumscribed the opportunity for inventive genius as to the construction of wing surfaces at the time Montgomery designed his structure. The latitude for novelty in this respect was limited to sui generis forms and modes of adjustment. The necessity for curved wings and wing warping had been anticipated. It had been successfully demonstrated in an empirical way, and was distinctly recognized as an established principle of aeroplane flight, so that Montgomery, as the history of his application for and allowance of patent expressly discloses, was limited to the precise disclosure of his claims in this respect. Preceding 1905, inventors were active in the art. Intensive study and experimentation were in progress on a large scale, and the record absolutely precludes the possibility of assigning to Montgomery more than his claims specifically call for, and to that precise limitation we think his patent is restrained, including the claims grouped in group one. The defendant furnished the plaintiffs with plans and specifications of two flying machines, illustrative of the character of machines being used by the Government at the time the petition herein was filed. Both parties have used and relied upon these machines as determinative of the issue of infringement. They are known in the record as Exhibits #114 and 115, the latter being known as the “ flying boat.”

The plaintiffs contend, quoting from one of their expert witnesses, that in both Government machines “ the wing surfaces have a curvature and are not of flat plate. They are a refinement of the parabolic or cambered wing principle. The wings have hinged ailerons at their rear parts, giving a variable curvature to the wing, the front portion remaining rigid, which is similar to and identical in principle with what the Montgomery patent provides for.” Taking the above contention literally, as expressed above, it is apparent that the wing surfaces of the alleged infringing' airplanes are not the exact counterpart of those claimed in the patent. Obviously, the wing surfaces of the Government planes are not curved parabolically. The Government wings are not identical in contour with respect to top and bottom, and the change effected in their surfaces is an angular change brought about by “ hinged ailerons ” on their rear portions. The patentee was compelled to amend his claims by the examiner, of the Patent Office to escape anticipation predicated upon hinged ailerons, and while the functioning element of hinged ailerons secures equilibrium and lateral control, the method adopted is quite distinct from that disclosed in Montgomery’s claims. The Government planes present no refinement of the parabolic principle. On the contrary, the completed wing structure discloses a perceptible divergence in both contour and breadth of construction. Montgomery’s wing surfaces were precisely the same on both top and bottom; there was no variance of contour; the cambered sections were identical, and being constructed out of a single layer of canvas obtained no variance in breadth. It is true the Government planes are rigid in their front portions, but the process of change of wing surface is not in any respect identical with Montgomery’s specifically claimed method of a change of curvature integral within the wing itself. We are unable to perceive the possibility of reading plaintiffs’ claims which call for a change of curvature in the plane surface upon the Government structure.

The second group of claims covers specifically the relative arrangement of supporting and control surfaces. Montgomery mounted upon his structure two wings arranged in tandem fashion; to the immediate rear of the second wing a large fin, practically semicircular in form, intersected midway by a smaller vertical plane, was so mounted and adjusted relatively with the control features of the device as to respond to a vertical movement. About midway between the first and second plane a saddle was suspended for occupation by the operator, his feet and arms being free to function the control adjustments.

Stability is, of course, an essential element in flying. If equilibrium is to be maintained, as pointed out by the record, the firmness of the structure and its ability to maintain equilibrium, both in lateral and other angles of flight, are of paramount importance. As pointed out in the defendant’s brief, “ stability is the property which tends automatically to restore an airplane to its position of equilibrium without application of the controls.” The art unquestionably teaches and has demonstrated long since that to avoid direct precipitation downward, known as “ nose dives,” and overcome any tendency to roll, tip, or pitch, either upwards, downwards, or sidewise, to restore a plane to equilibrium a form of construction must be made available, strong enough within itself to receive the pressure of the air either upon the top or bottom portions of its surface. From Montgomery’s claims in this group the contention is advanced that his rear wing acts as a stabilizer and secures the desired results; that the adjustment of the rear portions of the rear wing so as to effect a change of curvature, in connection with the movable fin and small vertical plane intersecting the same, capable of vertical movement, is the equivalent of the Government’s structure designed to secure stability and control. Accrediting expert testimony, especially where it harmonizes, two inescapable principles attach to stabilization: First, the stabilizing surface, as previously observed, must be of sufficient rigidity to withstand the pressure of a,ir currents upon both its upper and lower portions. It as frequently happens in the restoration of equilibrium that air pressure from above be obtained as from below; in each instance the necessity is due to the inclination of the airplane. Second, the angle of incidence becomes important. The stabilizing plane must be located at such a distance back from the center of gravity as to practically produce a zero angle of incidence relatively to the forward wing.

The stabilizing plane affords no support; it does not function as a “ lift.” While movable in some machines, in accord with certain required adjustments, it furnishes no sustentation; consequently, the development of the art clearly discloses that uniformly the stabilizing plane has been of much less dimensions than the supporting wings of the machine, and because of its location and mounting on the structure is incapable of performing the double function of aid in soaring and maintaining stability in flight. Montgomery’s rear wing, as specified and claimed, is inherently so constructed as not to be adapted to receive pressure from above; it functions as a companion to the forward wing in obtaining support and equilibrium. The very structure of the wing with its rear portions capable of change in curvature negatives the possibility of continued rigidity. While the front portions of the wing are stationary, the claimed novelty of a change of curvature precludes the possibility of the same conditions upon the rear portions, as they are admittedly flexible. There is nothing in the specifications or claims of Montgomery that points out a utilization of or the possible funq-tioning of his rear plane as a stabilizer. The specification recites “ investigation has shown me that a wing is a specially formed surface placed in such a position as to develop a rotary movement in the surrounding air. This position is determined by mathematical considerations. The movements in the air are of such a nature as to make it possible to separate the wing-surface, as I have done in my device, into front and rear sections and maintain the special rotary movement of the air which lies at the basis of this phenomenon.” The rear wing of the Montgomery patent was identical in contour and construction with the forward wing; its adjustment with relation to the control system, activated by the operator, clearly discloses, in our opinion, that the inventor did not contemplate or conceive the possibility of it functioning as a stabilizer. In addition to this, the record is convincing that the contention advanced to sustain the proposition fails to sustain as a principle of aerodynamics that the patentee’s rear wing is capable of functioning as claimed.

The stabilizing plane in the Government airplanes is located at and slightly extended over the rear end of the fuselage. It is stationary, less than 10% of the forward wing surface and set at a negative angle of incidence. The record is free from disputation that as so mounted and constructed it operates successfully as a stabilizing plane.

It is apparent that the stabilizer of the Government airplanes has a totally dissimilar function from that possessed by a supporting surface or aeroplane. It therefore becomes impossible to apply those claims of Montgomery (claims 12, 17, and 18), which call for “ plural curved airplanes, one in advance of the other,” to the Government structure by attempting to designate the stabilizer as the rear airplane without doing violence to the well-known doctrine of equivalents.

It is next insisted that Montgomery’s horizontal tail surface in the rear of his second wing, with means for swinging said tail surface vertically is the equivalent of the Government’s construction designed to afford directional control. Montgomery employed and his claims embrace the horizontal fin, intersected midway by the small vertical plane, the combination being so attached to the control adjustments as to function vertically upon the application of pressure by the operator. The Government planes utilize a small horizontal fin to the immediate rear of which is hinged a movable rudder functioning vertically. To the immediate rear of the Government’s stabilizing plane two distinct continuations of the plane are separately hinged, capable of vertical movements, known as elevators. Within the space separating the two elevators the horizontal rudder is afforded freedom of movement horizontally. The principle of equivalents is predicated upon the similarity of the functions the two devices perform. As said in Graham v. Mason, 5 Fish. 11:

Infringement depends not so much upon the form of the particular device in question, or upon the name given to it in the specification by the construction, as upon the functions it performs, and it is well-settled law that if one device is employed in a similar combination as another, and performs the same function in the same way, the two are substantially the same, although they may be different in form and may be known among mechanics by different names.”

Montgomeiy evidently followed in the wake of preceding-inventors in his conception of the rear surfaces necessary to secure directional control. The fin surface to which the vertical plane was permanently attached moved in unison vertically, and while it may have functioned to have in some degree afforded the desired control, it was not, so far as this record is concerned, adapted either as to location or construction to afford the two essential movements, i. e., the horizontal and vertical movements obtained by the Government machines through the horizontal rudder and the separate vertical elevators. These surfaces, as practical demonstrations proved, did not function in the same way the Government’s machines functioned. In addition to this, Prof. Langley’s article in McClure’s Magazine, published in 1891. both by description and illustration exhibited this form of structure and the principle wa,s clearly disclosed in the Wright brothers’ machine. True, the location in the Wrights’ machine was directly the opposite of what it was in Montgomery’s patent, but the functioning element of the device was precisely similar. Early inventors recognized the necessity for rear fin surfaces, a surface likened in the record to the feathered tip of an arrow, to secure directional control; it was not new.

The scope for invention was narrowed to a structure capable of utilizing air currents to obtain both lateral control and altitude. It would be difficult indeed to ascribe to Montgomery the first successful accomplishment of this purpose, in view of the prior art and the repeated decisions of the courts holding the Wright brothers to have been pioneer inventors in an art when this identical subject is of such vital importance. Wright Co. v. Herring-Curtiss Co., 211 Fed. 654, 117 Fed. 257, 204 Fed. 597; Wright Co. v. Herring-Curtiss Co. (C. C. A.), 180 Fed. 110; Wright Co. v. Paulhan, 177 Fed. 261; Wright Co. v. Paulhan (C. C. A.), 180 Fed. 112. The Montgomery device does not, in our opinion, disclose the essential elements to obtain the desired end. It was not accorded by those skilled in the art the possibility oí practical use, and demonstrations proved its inability to so function.

The third group of claims, i. e., 9,12, and 32, is apparently limited to a specific type or character of supporting surfaces defined in the claim as “ curved parabolically.” Claim 9 is typical of this group. It is in the following language :

“An aeroplane curved parabolically from front to rear, its front portion being rigid and its' rear portion adjustable, with means for adjusting said rear portion relatively to the front portion to change the surface of the aeroplane.”

The plaintiffs insist that the claims involved are not so limited; that the specifications iñ conjunction with relative claims involving character of wing surfaces clearly entitled the inventor to a broader construction of the claims in this respect. We have heretofore noted the cour,se of the pat-entee’s application through the Patent Office and the effect of the examiner’s ruling. A court called upon to construe a patentee’s claims finds therein significant technical words definite in character and imparting a distinct description in the art to which the claim appertains; obviously they are to be given effect; they may not be eliminated. The patentee had in mind something more than a generalization when he employed limiting words. The contour of supporting wing surfaces, as clearly disclosed by the great volume ,of expert testimony, was a factor which inventors recognized as of weighty importance. The distinct curvature and structural feature of wing surfaces, both as to upper and lower surfaces of the wings, afforded not alone the full measure of air pressure upon the lower surface but functioned to obtain the vacuum lift upon the upper .surface. ■ Curved wings, as previously observed, were not new. They were distinctly old in the art. This record is replete with old devices disclosing curved wings. True, many of the illustrations are crude, but the functioning of curved wings had been demonstrated prior to the advent of Montgomery, so that the significance of a parabolically curved wing is apparent. It is hardly possible that the Patent Office would have ascribed novelty to a curved wing surface. Montgomery was an experienced and educated inventor. He was not a mere adventurer in the art depending upon chance for a patent. In addition to his accomplishments as a scholar he possessed talents as a skilled mechanic, constructing his own devices, and his implicit faith in the soundness of his conceptions cost him his life. In view of this situation, with the whole of the English language at his command, we are prevented from concluding that he did not intend a specific limitation of wing surfaces when he used the words “ parabolically curved.” There was merit in a parabolically curved wing surface. Such a surface did function as the inventor contemplated it would, and while the question of the validity of Montgomery’s claims in this respect is an exceedingly close one, a question we need not' determine, we are of the opinion that the claims now under discussion were limited to this specific form of curvature.

It is an axiomatic principle of patent law too well sustained to warrant extensive citation that under the patent statutes the claims of the patentee define the patent, and when the language used is not obscure or ambiguous and has a settled meaning, courts are not at liberty to enlarge the same by construing them to intend something different. The Supreme Court in the case of White v. Dunbar, 119 U. S. 47, decided a similar contention to the one in this case. We think the decision apropos. The wing surfaces of the Government airplanes were not “ parabolically curved.” The dissimilarity is apparent.

We can not discuss in infinite detail the great number of technical and general issues raised by both sides in this case. We do not minimize the importance of the various contentions. Suffice it to say that in the opinion of the court the Montgomery patent, irrespective of its validity, was one limited to its peculiar structural features, a designed combination of elements old in the aft, utilized by the inventor to function in a certain novel way. The degree of novelty and invention to be ascribed to such a patent is limited to the specific device produced. The burden of estab-Iisbing the use of equivalents or the device itself is upon the inventor who alleges infringement, and granting to the plaintiffs the widest latitude in this respect we are unable to find from the record wherein the Government machines have trespassed upon the patentee’s devices or adapted equivalents in the structures it used. Subsequent to the Wright patent the art developed rapidly. The machines used by the Government functioned with a degree of success decidedly and emphatically impossible of attainment by the employment of any of the elements of Montgomery’s patent utilized as he utilized them. Whatever features of similarity in construction might be claimed between the Government and the Montgomery machines may only be found in a most technical evolution of obscure detail of construction and claims, which upon investigation disappear when tested by the prior art and faced with actual differences. The Montgomery and Government structures present such a distinct divergence of structural detail and functioning capacity that it is impossible to read the claims of the Montgomery patent upon the Government machines.

The petition will' be dismissed. It is so ordered.

Green, Judge; Moss, Judge; and Graham, Judge, concur.  