The front ends of the upper set of backing springs take their bearings at the two upper corners, respectively, of the frame-plate, or, as shown in the drawings, against shoulders on the bars, c, c', which bars are jointed to the frame plate at o' The rear ends of the springs abut against the ends of the keepers, k, k', and through the eyes of these keepers the bars, c, d, can slide. These keepers are shown in the drawings as bolted to the sides of the vestibule extension of the car body, and the coiled springs, t, t', are, for convenience, wound around the rods or bars, c, c'. In case there should be no vestibule extension of the car body, the keepers may be attached in any convenient way to the main body of the car, so as to furnish resisting abutments for the pressure springs, and guides for the rods connecting with the frameplate. The spring pressure to act against the lower portion of the frameplates is obtained, as exhibited in the drawings, from the coiled spring, m, which takes a bearing at one end against the solid frame-work of the car, and at the other end against a cross-head beneath the entrance platform car, which cross-head, by means of the rigid links, s, s', is connected with the threshold of the frame-plate, a, the said links or bars s, s', being knucklejointed to the threshold-plate, o."

The two claims, both of which it is alleged are infringed, read:

"(1) The combination with the end of a railway car of a frame-plate or equivalent series of buffers backed by springs, arranged with its face in a vertical plane, and normally projecting beyond the end of the car, whereby, upon the coupling of two cars, a spring buffer will be interposed between the superstructures of such adjacent cars above their platforms, and also frictional surfaces under opposing spring pressures to prevent the racking of the car frames upon sudden stoppages and to oppose the tendency of the cars to sway laterally when in motion, substantially as hereinbefore set forth. (2) The combination of a spring buffer or friction plate with the ends of the adjacent cars of a train, said buffers being located on the ends of the superstructures of the cars, respectively, and substantially at the tops of the same, and so arranged that when the two cars are coupled the faces of the buffers will bear against each other in contact under pressure, substantially as and for the purposes specified."

It is claimed that by attaching the Sessions organization rigidly to the car bodies, so that the frame-plates have no capacity to move sidewise independently of the movement of the cars, the frame-plates act as spring buffers in frictional contact under constantly opposing spring pressure between the superstructures of the cars, and that, thus combined with the ends of the cars, and acting in co-operation with the platform springs, the bufferplates are far more effective in dissipating the force of shocks in collisions, and in resisting the forces which tend to create oscillation, than if they were in close proximity, or even in frictional contact, but not under such pressure. It is not claimed that the improvement possesses the merit of entirely overcoming the tendency to oscillation in cars in motion. All that is claimed for it is the power to dissipate the force of shocks, and to resist and overcome the swaying tendency to an appreciable and useful degree, as compared with anything previously known in the art. The unevenness and curvatures in tracks cause cars in motion to vibrate, and it is claimed that the Sessions device possesses special merit, as compared with previous devices of the same character, in its ability to counteract the first impulses to these oscillatory movements. "It is common experience," says the specification, "that when a train of drawing-room or

sleeping-cars is traveling at high speed there is induced in each car a tendency to sway or oscillate laterally. The force which induces this tendency may be relatively a slight matter; but its continued repetition results in an aggregation of impulses which accelerate the oscillations and cause unpleasant effects upon the passengers especially when the road-bed has reverse curves, even of great radius. Especially is this experienced in trains of sleeping-cars which are provided with upper sleeping berths, constituting, when occupied, a weight elevated high above the center of gravity The effect of my improvement is to provide a resistance to this tendency to oscillation by checking the same at the outset before the impulses which produce it have accumulated. The surfaces of the springbacked frame-plates in contact are capable of resisting all ordinary impulses to oscillation induced by the movement of the train. Moreover, as the cars of a train do not generally sway in unison, but oscillate according to the effect of particular accidents or influences, the effect of combining the cars of a train by the aid of frictional surfaces in contact under considerable pressure, such as I have shown, is to dissipate all the lateral movements of each car throughout all the other cars so connected, and thus give steadiness to the whole train." The value of the Sessions device as a means of making collisions less injurious, and of diminishing the oscillation of cars in motion, and thereby promoting the safety and convenience of the traveling public, is abundantly established by the evidence in the record. Its prompt adoption by the leading railroads of the country, especially the Baltimore & Ohio, with its numerous sharp curves, attests its merits, and the large number of intelligent witnesses, many of them disinterested, who have testified from experience and observation of its steadying effect, leave no room for doubt upon this branch of the case. Persons, traveling on cars equipped with the improvement, are less affected by swaying movements than when traveling on cars not so equipped. Persons troubled with nausea experience less discomfort on trains operated with the improvement attached than when traveling on cars not so operated. Persons occupying upper berths of cars operated with the improvement attached experience less discomfort than previously, and trains operated with the improvement have sustained less injury in collision than trains colliding without it. These results are attributable to the Sessions device. On the evidence they can be accounted for in no other way.

Before discussing the patents, machines, and publications, which are relied on as anticipations of the Sessions improvement, we will briefly advert to the marked difference between English and American railway cars, American cars of the Pullman and Wagner class are from 50 to 80 feet long, 10 feet or more high, and rest at either end upon six and eight wheel trucks. The cars and trucks are connected by means of swiveling joints, to allow the cars to keep the track, and turn curves. The floors or platforms rest upon the trucks; and the cars, which are heavy, are necessarily strongly braced and trussed to stand the severe strain to which they are subjected. English cars are about one-third the length and twothirds the height of American cars. They are mounted on two axles in

rigid down-hangings, secured to the sills of the platforms, so as to admit of a vertical spring movement. They have no swiveling attachment or movement, for the easy turning of curves, and the car bodies are necessarily short, so short as to be within the unit of each curve they travel, otherwise they would leave the track. Owing to their comparative great length and height, our American cars, in motion, have a stronger tendency to sway than English cars. If it were possible to operate American cars with platform buffers three or four feet from the center of oscillation, as in England, there would be less necessity for the Sessions device, or indeed, for elevated buffers of any kind. As to the platform buffers described in the English and American patents found in the defendants' record, it is sufficient to say that in construction and mode of operation they are unlike the Sessions frame-plates in frictional contact under constantly opposing spring pressure interposed between the superstructures of the car bodies, and so attached to them that part of the force of the bottom or platform springs is transmitted along the frame-plates to their tops. While the Miller coupler and buffer, with its single central pair of coupling faces, and the Janney coupler and buffers, with their faces 26 inches apart, were great improvements on previous means of coupling American cars, they lacked the essential elements or features which characterize the Sessions organization. The English patent granted to Symons in 1847 describes buffers attached to the ends of cars at or near the top as distinguished from platform buffers, or buffers lower down on the car ends, so that in case of shocks or collisions the top buffers may come in contact and press upon each other, and thereby prevent the force of the lower buffers from causing the cars to rise and fall upon or override each other. The idea of these top buffers being in contact under spring pressure to prevent or diminish oscillation, is nowhere suggested in the specifications. It is only in case of collisions and sudden concussions that they are forced into contact. In order to steady the car bodies, and prevent them from swaying under ordinary conditions, the faces of these elevated buffers should be in frictional contact, which is not the case. It is true, the patent speaks of a means of diminishing oscillation, but it is in connection with an improvement for the purpose of traction or propulsion. In explaining the advantage of connecting the carriages for traction at two points instead of one, as was then usual, the specifications say:

"It is obvious that when carriages in a train moving at high velocity are attached to each other only at one point in the center, as at present is the practice, they must have a separate tendency (especially the last carriages) to oscillate or rock from rail to rail if the slightest obstacle be presented on the rail to either of the wheels on the side of the flange. It is also obvious that, if the carriages are attached at two points, as above provided for, the tendency to oscillate would be counteracted, if not obviated entirely."

The top buffers described in this patent are shown in sections of spheres, for which reason, as well as others already mentioned, they are not capable of diminishing oscillation. The English patent granted to Dyer in 1864 shows elevated buffers, intended "to alter or change the

line of concussion, in order to lessen the tendency of the carriages to overturn, or rise on end, in the event of collision." These buffers, like the Symons top buffers, are not in contact under ordinary conditions, and, in view of the office which they are expected to perform, it is not necessary that they should be. It is only in case of collisions, or violent, sudden shocks, that they are brought into play. The means designed to prevent oscillation are thus described:

"I propose to place the wheels at the sides of the carriages, to bring the center of gravity within or between the wheels, and thus prevent oscillation, and give increased steadiness and security to the carriage. I propose to make the wheels revolve on their axles, instead of being fixtures thereto, so as to prevent the danger attendant on traveling round curves, and also to lessen the injurious results of oscillation upon the nervous system of passengers. I also propose to increase the diameter of the wheels to about five feet, or about equal to the base or breadth of the carriage, or less, as may be required, to resist the overhanging weight and tendency to overturn, and to give greater steadiness to the motion of the carriage generally."

If the elevated buffers were intended to be in contact as a means of preventing oscillation, and if they are in fact so shown in the patent and drawings, why did the patentee describe other and different means for that purpose without mentioning the elevated buffers in the same connection? But, treating them as in contact, they are not under such spring pressure as to produce friction which will resist the tendency of cars to sway to any appreciable extent, as the Sessions buffers do. The English Garvey patent of 1852 is "for more effectually dissipating the shock of collision in railway trains, reducing the surface exposed to atmospheric resistance, and diminishing oscillation." The means employed by the patentee for accomplishing the last-named purpose are described in the specifications to be shields or frames attached to and covering the end of the cars, which frames are supported on the ends of four iron rods, attached rigidly to the car body, at or near its four corners. The shields are attached to the ends of the rods by means of volute springs. They are light, and covered with felt, and are forced into close contact when the cars are screwed together into a train by means of draw-links. The shields are capable, however, of moving vertically or "laterally, independently of the rods" which support them, and they would therefore be worthless as a means of resisting the tendency of American cars to oscillate. Whatever merit this device has in diminishing lateral movements of cars consists in the pressure of the volute springs. In speaking of the action of these shields, the specifications say:

"As these surfaces are covered with thick and strong felt, they cohere sufficiently to prevent them from sliding over each other, whilst the shields, possessing a universal mobility, will remain in close contact with each other, whatever may be the position of the carriages, whether they are turning a curve, or passing over a rise, or running on a line."

Although this device may somewhat diminish oscillation, not by the friction of the shields in contact, but by the force of the volute springs, it is different in principle from the means employed by Ses

sions for accomplishing the same purpose, namely, frictional resistance afforded by two vertical frame-plates in contact under constant opposing spring pressure capable of moving on each other, and yet resisting the tendency to move, and so attached to the car bodies that the force of the platform buffers is effectively transmitted along the plates, even to their tops. The Waller provisional specification of 1871 is relied on as a publication. The means employed, "by which, in case of a collision taking place, or a tire being broken, the injury to passengers is greatly diminished," are as follows: The entire ends of the cars are covered with a sheet of rubber one inch thick, which, in turn, is covered with sheet-iron three-eighths of an inch thick, upon which fourteen, or more, rubber sockets, each one foot square and one inch thick, are placed to receive an equal number of spiral flat springs, two feet long when not compressed India-rubber sockets cover the outer ends of these springs, which sockets are covered with sheet-iron plates, tied together by flat strips of metal. Over all this is placed another sheet of India-rubber, half an inch thick. "The carriages," say the specifications, "constructed in this way, when coupled, touch one another on a surface of not less than 30 square feet, the springs being then reduced to one foot nine inches in length, and the whole train becomes a solid and flexible mass, so that it is impossible for one buffer not to act upon another. It will be remarked that I never have two ordinary surfaces touching each other, which is an important feature." There is a wide difference in organization and mode of operation between this mass of compressed rubber and springs attached to the ends of railway cars, and the Sessions device, as already explained. The English patent of 1845 to Fuller describes elastic cushions, or leather or rubber sacks filled with wool, or other flexible material, and interposed between the ends of cars, so that in case of collision, the cushions may diminish the effect of the concussion. The cushions are made on strong wooden, or metal, frames attached vertically to the ends of the cars, and backed by strong springs on sliding rods attached to the cars at the top and bottom by long iron sockets. These cushions, which act as buffers, are intended to be used with or without the ordinary buffers. If these cushion buffers are shown in contact, under ordinary conditions, they do not operate as frictional surfaces, like the Sessions frame-plates. The principle upon which the two organizations act is not the same. The English Bessemer patent of 1847 is, in part, for a hood-like organization to close the open space between the ends of cars in a train, and thereby avoid the resistance of atmospheric pressure when the cars are running at a high rate of speed. The hood is described as similar to the hood of the ordinary road carriage. The frame-plate or bow is pivoted at the bottom to the buffers, moves with them, and is forced out at the top by a spring. The device is somewhat difficult to understand, but it is so constructed and provided with hinges, springs, pins, rods, cranks, and levers as to be capable of being expanded and folded back. In one form it is described as attached to a wooden structure built out from the car equal to half the space between the cars in a train. Frictional resistance, as a means