one integral, flat piece, large enough to reform by a single impression the surface of the whole plate. But this construction is forced. No doubt there must be complete contact between the die and the glass over the entire area sought to be affected by the particular impression which, at any one time, is being made. But there is nothing which requires that this should be coextensive with the whole sheet, or that is not fulfilled in principle as in terms by a molding of the sheet, by successive contacts, with a die which only covers a section at a time. That is the action of the defendants' grouped sectional dies, which perform substantially the same function as that of the complainants' single die; the result, when the operation is complete, being also the same, and affected in essentially the same way, which is not to be obscured by the fact that it is divided up, and the sections successively applied, a familiar expedient of infringers, to get the benefit of the principle, while possibly avoiding the letter.

It is contended, however, that the defendants have no air vents for the cavities of their dies such as are called for by the claim. These are made a feature of the device, and cannot be ignored, however unimportant they may seem. And, if the complainants are confined to those which are shown in the drawings, the defendants, not making use of that particular form, do not offend. But no such limitation is imposed. On the contrary, it is expressly declared in the specifications that, where the prism forming cavities extend across the face of the die, the end of each cavity may be left open to provide the needed vent. This is the exact construction adopted by the defendants, which none the less constitutes a vent within the terms of the claim-sustaining the infringement charged-because, by the arrangement, the air escapes naturally without any specially provided port.

Another distinction which is suggested is that the cam by which the defendants' dies are depressed is indented at the center, so as to allow each die to slightly rise at that point, as it is reached, being forced back into contact with the glass, as the cam proceeds, until released at the other end. This, as it is said, is a desirable as well as a distinguishing feature, insuring, as it does, that the glass shall not stick. But, whether this be so or not, it amounts at the most to a mere variation or improvement, making no substantial change in the operation, the essentials of which remain the same.

The operation of the defendants' apparatus is also claimed to be different, because a wave of glass precedes the dies across the sheet, which is not thus in plate form, as it is said, when the prisms are impressed. But this loses sight of the effect of the completed operation, which, regardless of the wave, by the separate action of roller and dies. produces in the end a properly constituted pressed prism plate.

Nor are the defendants much more fortunate in avoiding the method patent. There are four claims here, all of which are relied upon, as follows:

"1. The herein-described method of making prism-plates of large area in two operations, consisting in producing a substantially flat sheet of glass, and then forming prisms on the surface of the sheet by pressure exerted in a direction transverse to the plane of the sheet upon the entire cross-section of the portion to be shaped into prisms; substantially as described.

"2. In the manufacture of prism-plates, first spreading the glass into a

sheet of at least the dimensions of the completed article while the same is freely plastic, whereby change in the relation of the particles is unaccompanied by increased tension of any part of the mass, and then (leaving the glass sheet of the dimensions so constituted and without further spreading the glass) forming on the surface of the sheet while still plastic prisms over the entire portion to be shaped and confining the prisms until the glass thereof has set; substantially as described.

"3. The herein-described method of making prism-plates of large area in two operations, consisting in producing a substantially flat sheet of glass, and then forming prisms on the surface of the sheet by pressure exerted in a direction transverse to the plane of the sheet, upon the entire cross-section of the portion to be shaped, and confining the prisms until the glass has set; substantially as described.

"4. The herein-described method of making prism-plates in two operations, which consists in producing a substantially flat sheet of glass, and then while it is still plastic applying pressure to the surface thereof in a direction transverse to the plane of the sheet and upon the entire surface to be shaped into prisms, segregating thereby portions of the plastic glass, and displacing the same upwardly into ridges of prism form, whereby the prism-plate is formed without unequal straining of the glass; substantially as described."

The point is made, as to this, the same as the apparatus patent, that there has to be a contact of the die, at one and the same time, over the entire surface of the plate. But even less, indeed, than there, is there anything upon which to predicate this. The most that is required in any of the claims is that prisms shall be formed "by pressure exerted in a direction transverse to the plane of the sheet upon the entire cross-section of the portion" to be shaped; and this is clearly satisfied as well by impressing the surface with prisms in successive sections as by subjecting it to the action of a single die, operating upon the whole.

It is said, however, that the complainants' process is not only a divided, but an interrupted, one, while that of the defendants is continuous. By the one as it is pointed out the glass is first spread by the roller, "and then," in the words of the several claims-that is to say, after this part of the operation is over, and not until then-are the prisms to be formed on the surface. A distinct interval, in other words, is to occur, according to this, the object of which, as shown by the specifications, is to let the glass set or cool, and so "retain the prismpattern which is formed upon it, without losing it by the running together of the hot glass, or without burning the sharp projecting portion of the figured surface of the die." But, with an exception to be presently noted, this is not the construction to be given to the claims. Undoubtedly there is an intended division of the operation; that, indeed, being its real virtue. But so is there in that of the defendants; which is essentially the same; the glass being first spread by the roller, and then pressed into prisms by the following dies. There may be no great interval between the two parts of the operation, nor much cooling or setting of the glass. But there is enough to be appreciable, and to make the operation a divided one, appropriating the principle of the invention, as is clearly shown by comparison with the original arrangement devised by Shuman, by which the glass was to be both spread and pressed by means of the dies, without more. Whether structural strain was found to result, as in the Heidt, or sharply-defined prism angles could not be formed, as in the Cummings, this was aban

doned, as we have seen, and the operation split up, two parts being made of it, the one devoted strictly to rolling out the sheet, and the other to impressing prisms thereon. But this is the Ripley and Wadsworth method, pure and simple, the essential feature of which consists not so much in having a cooling interval between the two steps of the process (although that may not be without its advantages) as in the separation of them, so as to avoid undue tension or strain, the formation of the prisms not being undertaken, until after the glass has been spread; there being nothing, however, to require that the spreading shall be complete over the entire sheet before the prism making is begun.

The same cannot be said, however, of the second claim, as to whichas intimated an exception must be made. The provision there is express, for "first spreading the glass into a sheet of at least the dimensions of the completed article * * * and then (leaving the glass sheet of the dimensions so constituted and without further spreading the glass) forming on the surface of the sheet, while still plastic, prisms over the entire portion to be shaped." Here is apparently a distinct and intentional cleavage between the two steps of the process, possibly designed to carry out the suggestion for a cooling interval made in the specifications, and to cover a modification in which that was found, which cannot be disregarded or put aside. Not but that considerable of an argument can be made that nothing more was intended than appears in the other claims. But that is not the natural or obvious construction; and, the claims having to be differentiated in order to avoid duplication, it may be conveniently done this way. way. At all events, the burden is on the complainants to establish infringement which is not made out, if it is uncertain as to what is the true reading of the claim. Let a decree be drawn sustaining the bill, and granting the relief prayed for, except as to the manufactured article and the second claim of the method patent, with costs.

LIDGERWOOD MFG. CO. v. LAMBERT HOISTING ENGINE CO.

(Circuit Court, D. New Jersey. January 30, 1907.)

1. PATENTS-INFRINGEMENT-CABLE CONVEYORS.

The North patent, No. 480,029, for a conveying apparatus, relating to cable conveyors, and the essential feature of which is a self-propelling and self-distributing fall-rope carrier, was not anticipated and discloses invention. Also held infringed.

2. SAME-INVENTION.

The Dusedau patent, No. 548,973, for a cable-hoist, is void for lack of invention.

3. SAME-INFRINGEMENT-EQUIVALENT PARTS.

Two wheels or pulleys connected together so as to revolve as one by bolts or other close fastenings, and a single wheel cast with two peripheral contacts, are mechanical equivalents, where they operate in the same manner to produce the same result, and the substitution of one for the other in a patented device does not avoid infringement.

In Equity. On final hearing.

Gifford and Bull (Livingston Gifford, of counsel), for complainant. Edward M. Colie (William Houston Kenyon, of counsel), for defendant.

CROSS, District Judge. This matter is before the court upon final hearing on bill, answer, replication, and proofs, and involves the validity of two patents and their infringement by the defendant. The first patent in suit, No. 480,029, for a conveying apparatus, was issued August 2, 1892, to Charles M. North, assignor to the complainant, and the second, No. 548,973, for a cable-hoist, was issued October 29, 1895, to one Wilhelm Dusedau, and assigned to the complainant June 6, 1902.

Claims 1, 6, 7, 8, 9, and 10 of the patent No. 480,029 are involved, and are as follows:

"(1) In a conveying apparatus, in combination, a cable or trackway, a loadcarriage, a rope traveling therewith, and a rope-carrier containing a wheel adapted to be turned by said traveling rope, a wheel adapted to bear against the cable, or trackway, and connections between said two wheels, whereby the rotation of the first is communicated to the second, substantially as described." "(6) In a conveying apparatus, in combination, a cable or trackway, a loadcarriage, a rope extending to said load-carriage and running approximately parallel with the cable or trackway, and a rope-carrier mounting the following parts, viz.; a traction device adapted to travel on the cable or trackway and mechanism actuated by said rope, whereby the movement of said traction device, and thereby that of the carrier, is controlled, substantially as described. "(7) In a conveying apparatus, in combination, a cable or trackway, a loadcarriage, a rope extending to said carriage and running approximately parallel with the cable or trackway, and a series of rope-carriers, each of which mounts the following parts, viz.; a traction device adapted to travel on the cable or trackway and mechanism actuated by said traveling rope, whereby the movement of said traction device, and thereby that of the carrier, is controlled, substantially as described.

"(8) In a conveying apparatus containing a cable or trackway, a carriage, a rope extending to said carriage and running approximately parallel with the cable or trackway, a rope-carrier, a device mounted on said carrier, adapted to travel on the cable or trackway, and a device mounted on said carrier, adapted to engage with said rope, the combination, with said devices, of connections whereby the motions of one of said devices are communicated to the other, substantially as described.

"(9) In a conveying apparatus containing a cable or trackway, a carriage, a rope extending to said carriage and running approximately parallel with the cable or trackway, a series of rope-carriers, a device mounted on each of said carriers, adapted to travel on the cable or trackway, and a device mounted on each of said carriers, adapted to engage with said rope, the combination, with said devices on each carrier, of connections whereby the motions of one are transmitted to the other, the speed of said transmission being in decreasing series from the carriage toward the end of the cable or trackway, substantially as described.

"(10) In a conveying apparatus, in combination, a load-carriage, a cable or trackway, a member connected with the carriage and extending along the cable or trackway, a rope-carrier, mechanism mounted thereon engaging with and driven by said member, propelling mechanism, also mounted upon said carrier, and means whereby the movement of the mechanism driven by said member is communicated at a reduced speed to said propelling mechanism, substantially as described."

Both of these patents in suit have to do with the use of a cableway, which consists in general of a cable stretched between the tops of two towers or supports, over which cable a load is conveyed from point

to point, suspended from a load-carriage, which is supported from the cable by wheels running freely thereon. There is also a haul-rope fastened to opposite sides of the load-carriage and running to each tower, whereby the carriage is hauled back and forth along the cable. What is called a "fall-rope" holds the load in suspension from the load-carriage, and extends from it along the cable to the tower at which the engine is located, called the "head-tower," and thence to the engine. By hauling in or paying out this fall-rope, the engine can raise or lower the load at any point along the cable to which the load-carriage may be run. It is obvious from what has been said that so long as there is a load attached to the end of the fall-rope that rope will be taut, and it is equally obvious that, when the load is released from the fall-rope, it will, because its body is heavier than its unloaded end, slacken and sag between the load-carrier and the tower, and that, while in this condition, the unloaded end of the fall-rope could not again be lowered to take on a new load. For a long time prior to the issue. of the North patent it had been a problem how to prevent the fall-rope from sagging or bellying when the load was released, and, to obviate or lessen the difficulty, rope-carriers, as they are called, of various kinds had been invented to sustain the fall-rope at all times, whether loaded or unloaded, on a level, and as nearly parallel as might be, with the cable. To accomplish this successfully, it was necessary that the rope-carriers should move in succession from the tower after the load-carriage, and severally arrange themselves in a proper position to support the fall-rope, no matter where the position of the load-carriage might be. Several patents were issued covering different devices intended to accomplish the desired end, and a number of them have been cited by the defendant as anticipations of North's invention, but they seem to me to be so far removed from what North accomplished as not to require special or detailed consideration. North was the first to employ a self-regulating fall-rope carrier. "Heretofore it has been customary," adopting the language of his specification, "in apparatus, employing a load supporting carriage traveling on a cable and also employing traveling rope-carriers, to regulate the travel of the rope-carriers either by flexible connections between them or by stops located along their path of travel and cause them to follow the carriage in its outward movement either by an attachment between them and the carriage, or by their own gravity. My invention has for its object to provide new means whereby the travel of the rope-carriers is actuated and regulated, and it consists of driven mechanism whereby the carrier is caused to progress along the cable or trackway, * * * this fall-rope or endless rope, as the case may be, acts as a motor to drive the mechanism located upon each of the carriers, and engaging with the cable and thereby causes each carrier to follow the carriage, though with less speed. The speed at which each carrier advances will be regulated by the diameter of the wheels or gears interposed between the sheave receiving motion from the fall-rope, or the endless rope and the sheave bearing against the cable, so that in the series of ropecarriers on each side of the carriage, each one of the series will travel faster than those farther away from the carriage. By this means each