Opinion of the Court 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: Opinion of the Court 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 aeroplanes 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 h, causes the corner h to move downward in unison with the corner d. Since the corner a thus moves upward and the corner h moves downward, that portion of the rope 19 connected to the corner a will be pulled upward through the pulley 20 at the corner h, 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 other side of the machine upward. This results in a downward movement of the corner b and an upward movement of the corner c. 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 h at one side of the machine are moved Opinion of the Court 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 aeroplanes, 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 Opinion of the Court 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 Opinion of the Court 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. It 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. 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 |