This deficiency of the Westinghouse brake in the stage of improvement which it had reached in Patent No. 220,556, from whatever cause resulting, created the necessity for some additional invention by which, on sudden emergencies in the presence of immediate danger, a long train of cars in rapid motion should be immediately brought to an abrupt stoppage by an instantaneous and simultaneous application of all the brakes of every car. The thing wanted was what has technically come to be called "quick action."

Each of the chief contestants in the present suit set himself laudably to work in devising a means to accomplish this important desideratum, each taking the air-brake patented as No. 220,556, Westinghouse's exclusive property in which has expired, as the basis of his new device, the common object being to produce a mechanism by which to secure instantaneously, whenever and only when a sudden emergency arose, such a quickened discharge of compressed air into the several brakecylinders that each car would simultaneously and the entire train as a whole be brought to a sudden halt, but leaving all the mechanism already existing for use in ordinary braking unmolested and unchanged. Counsel for appellees (Westinghouse) in his oral argument well described the need that was to be supplied when he said:

Quick action does not involve greater power of the brake; it is not a question of greater force of brake, as applied to the brake-shoes of any individual car. The force with which the brake-shoes are applied to any individual car is no greater with the Westinghouse quick-action brake (No. 360,070,) which is in controversy here, than it was with the old automatic brake (No. 220,556.) The engineer is, in both cases, operating with seventy pounds of pressure in the main reservoir on the locomotive and in the auxiliary reservoirs on the cars throughout the train, and in the system of pipes thronghout the train, and all the force he can possibly apply with the present quick-action brake (No. 360,070,) or with the old automatic brake (No. 220,556,) is seventy pounds of pressure to the piston of the brake-cylinder, and through it to the brake-shoes.

And the same counsel well described the desideratum sought forthe gist of the urgent need-when he said that its characteristic must be

the utilization of auxiliary-reservoir pressure for service or for graduation, when you do not need to use quick action; but when you want to get what is known in the art as "quick action," when the question of life or death is to be settled in a few seconds, then the pressure from the train-pipe (which comes from the main reservoir on the locomotive) is to be utilized for that purpose.

Westinghouse devised for each car an additional valve, which he so attached to the triple valve of Patent No. 220,556 that when the piston should be in complete traverse and driven to the end of its chamber it should drive forward an additional stem provided for this additional valve, and thereby open a port in that valve by which compressed air from the train-pipe should pass through by-passages independent of the triple valve into the brake cylinder into which the triple valve vented compressed air from the auxiliary reservoir. By this device of

the additional stem, the additional valve, and the independent by-passages into which the latter opened the inventor contrived to discharge compressed air from both the auxiliary reservoir and the train-pipe into the brake-cylinder of each car simultaneously, and thereby so quickened the action of the brakes as to accomplish the desideratum of quick action. To repeat, his device for this purpose consisted in attaching to the pre-existing triple valve, as patented in No. 220,556, a machine which embraced an additional stem, an additional valve, and additional air-passages leading from the port in the new valve to the brake-cylinder. This new attachment is put into action for emergency purposes by the triple-valve piston when on its extreme traverse. The previous machine, No. 220,556, had provided for the extreme traverse of that piston by which it had put in action the main valve at the end of its old stem and opened a full and direct flow of compressed air from the auxiliary reservoir into the brake cylinder for use in emergencies. Thus the new contrivance by the same extreme traverse of the triple-valve piston continued the old flow of compressed air for emergency purposes and provided an additional flow of the air for emergency purposes by an additional mechanism, this latter flow being directly from the train-pipe, and the former flow being from the auxiliary reservoir. Such was the make up of Patent No. 360,070-two machines in one box or case. It was found on thorough and conspicuous trials to be imperfect and inefficient and lacked that essential element of patented devices-utility; but it contained a valuable invention and was afterward so improved in details, when patented in No. 376,837, as to become a machine of great value to the public, a supplemental piston being supplied in No. 376,837.

Boyden also made a successful invention of venting compressed air from the train-pipe into the brake cylinder of each car simultaneously with venting air from the auxiliary reservoir to the brake-cylinder, as had been done for emergency purposes by the previous triple valve of Patent No. 220,556. He did not resort to a second machine. He did not devise an additional stem, an additional valve, or by-passages independent of those of the triple valve. He accomplished the transmis sion of compressed air directly from the train-pipe to the brake-cylinder by other means. He inserted a partition in the form of a brass ring into the triple valve of Patent No. 220,556 itself, between the chamber containing the valves and the compressed air of the auxiliary reservoir, on one hand, and the chamber of the piston containing train-pipe air on the other, and he opened a port in that partition for the passage of compressed air from the train-pipe to the brake-cylinder. He thereby so provided that whereas Westinghouse's device employed a fourth valve, another stem, and newly-contrived by-passages for discharging compressed air from the train-pipe into the brake-cylinder, organized separately in a second machine, Boyden contrived to discharge both

train-pipe air and auxiliary-reservoir air simultaneously into the brakecylinder without using an additional stem or valve or by-passages. The devices of Westinghouse and Boyden are exhibited by the diagrams on the sheet inserted between pages 34 and 35 of appellant's (Boyden's) principal brief and are attached to this statement. Let these diagrams be made a part of this opinion.

NOTE. The check-valve 49 is located back of the passage 18 and therefore is not visible on Cut 7.

It is not for us to describe how the introduction of train pipe air into the brake-cylinder of each car quickens the action of the brakes, which are already subject to the action of air from the auxiliary reservoir. It is sufficient to say that the engineer by means of his valve on the engine and by means of the branch pipe leading from the train-pipe to the triple valve of each car can by the improvements in controversy vent the air of the train-pipe directly and more promptly into the brake-cylinder, and thus more quickly apply the brakes, than he can by the indirect conduit opened by the main valve of No. 220,556 into

the brake-cylinder from the auxiliary reservoir when its piston is in extreme traverse, as heretofore described. Quick action being the desideratum the engineer effects it more promptly by the direct means than by the indirect.

Before GOFF, SIMONTON, and HUGHES, Judges.

HUGHES, J.:

The foregoing statement of facts and explanation of the devices upon which the decision of this case depends is of unusual length, which has been a necessary result of the extraordinary magnitude of the record and the unusual number and volume of the briefs of counsel in the

case; but it has been prepared at the expense of very much labor, and is, we trust, sufficiently correct to warrant the conclusions of law which we have founded upon them.

Of the technical "claims" set out by Westinghouse in his application for the Patent No. 360,070 those numbered 1, 2, and 4 are the special subjects of this suit. The device described in these claims is the one which Westinghouse charges in the bill of complaint in this case to have been infringed by the Boyden invention. The three claims are as follows, and the words in Italics indicate the device charged to have been infringed:

1. In a brake mechanism, the combination of a main air-pipe, an auxiliary reservoir, a brake-cylinder, a triple valve, and an auxiliary-valve device, actuated by the

piston of the triple valve and independent of the main valve thereof, for admitting air in the application of the brake directly from the main air-pipe to the brake-cylinder, substantially as set forth.

2. In a brake mechanism, the combination of a main air-pipe, an auxiliary reservoir, a brake-cylinder, and a triple valve having a piston whose preliminary traverse admits air from the auxiliary reservoir to the brake-cylinder, and which by a further traverse admits air directly from the main air-pipe to the brake-cylinder, substantially as set forth.

4. The combination, in a triple-valve device, of a case or chest, a piston fixed upon a stem and working in a chamber therein, a valve moving with the piston-stem and governing ports and passages in the case leading to connections with an anxiliary reservoir and a brake-cylinder and to the atmosphere, respectively, and an auxiliary valve actuated by the piston-stem and controlling communication between passages leading to connections with a main air-pipe and with the brake-cylinder, respectively, subtantially as set forth.

The phrase "substantially as set forth" is technical and is equiva lent to saying

by the means described in the text of the inventor's application for Letters Patent, as illustrated by the drawings, diagrams, and models which accompany the application.

• These words limit the general terms of the specification which set out the function performed by the invention and confine the inventor's rights to his own means or their mechanical equivalent of performing the function.

It is unnecessary to set out in totidem verbis the technical "claims" in which Boyden summarized his application to the Patent Office. Suffice it to say that his device, original and improved, which is represented in the patents issued to him as Nos. 481,134, 481,135, and 481,136, dated August 16, 1892, provided for the admission by a single valve integral with the triple valve of both train-pipe air and auxiliaryreservoir air to the brake-cylinder for emergency stops. He accomplished this object, as Westinghouse did, by a device acted upon by the triple-valve piston when at the same extreme traverse at which it had been previously used for emergency work. As to using this extreme traverse, described in the patent which expired, No. 220,556, he did what Westinghouse did; but the object of either being the discharge of train-pipe air into the brake-cylinder (which was new) simultaneously with the discharge of auxiliary-reservoir air into that cylinder (which was old) Boyden invented a partitioning-ring in the old triple valve to divide the chamber of the three valves from the chamber of the piston, and opened in this ring a port through which the train-pipe air might pass from the piston-chamber through the chamber of the valves to the brake-cylinder, while Westinghouse attached an additional and individual machine to Patent No. 220,556, consisting of a stem moved by the main piston in extreme traverse, an additional valve, and additional independent by-passages leading from the additional valve to the brake-cylinder. The same result was accomplished by the two devices; but these had but one means in common. Each used one common