Opinion of the Court.

a ridge. Again this new block of material, by reason of frost or from other causes, is frequently torn loose from its soldered connection with the old material, thus necessitating new repairs. In practicing my invention, however, I subject the spot to be repaired and the surrounding edges to such a degree of heat that the surface asphalt, not only the exact spot to be repaired but the surrounding portion, to a greater or less degree, is reduced to the soft pliable state in which it is originally laid. With a rake or other suitable instrument it is then agitated and mixed with enough new material to fill up the spot to be repaired. It is then subjected to the usual finishing operation of ironing and burnishing. The heating of the surface may be accomplished in various ways and by means of various forms of apparatus, and while I have herein shown but one form for accomplishing the result, yet I would have it understood that I do not limit myself to any particular form of apparatus for carrying out my invention."

The apparatus described consists of a suitable tank mounted on a wheel for carrying gasoline. The tank is connected with a series of horizontal pipes which carry a series of burners, and "project a flame downward against the pavement."

"In carrying out the invention A represents a suitable tank for carrying gasoline mounted on the wheeled frame B and connected by the pipe C with a series of horizontal pipes, D. These pipes D'carry a series of burners, E, which pass through a hood or shield, F, and project a flame downward against the pavement. Pressure is thus obtained upon the gasoline to force it to the burners and to produce a blast by means of an air pump, G, mounted upon the tank."

The letters patent further say:

"The apparatus is also provided with a handle, H, whereby the operator may readily move it to the desired spot. Now as would be seen by turning on as many of the burners as are desired, a strong blast of heat is projected against the surface of the asphalt and readily melts it. As explained above, when it is desired to repair a spot the apparatus is moved adjacent thereto with the burners directly above the spot. These soon reduce the surface asphalt, both at the spot and at the surrounding

VOL. CLXXXIII-38

Opinion of the Court.

edges, to a pliable state, the strong blast causing not only the immediate surface, but the particles deep down, to be melted and yet not burned. With a rake or other suitable instrument the operator then agitates or stirs up the softened material, and by adding new material of substantially the same degree of softness the spot or depression to be repaired is filled up and subjected to the usual smoothing and finishing operation as in the case of a new pavement. This, as will be seen, is done without the use of the tar for the purpose of uniting the parts or sections of material, and is done without any distinct divid ing line between the old and new material. In fact, there is no dividing line, because the new material has been mixed with and becomes a part of the old material. As stated above, while heating the spot to be repaired the surrounding edges or portions must be heated to a greater or less degree, and the new material is worked into these edges as well as in the spot to be repaired, so that when hardened it is practically impossible to tell where the pavement has been repaired.

"What I claim is

"1. The method of repairing asphalt pavements, which consists in subjecting the spot to be repaired to heat, adding new material and smoothing and burnishing it, substantially as described.

"2. The method of repairing asphalt pavements, which consists in subjecting the spot to be repaired to heat until the material is softened, agitating it and mixing with it new material, and finally smoothing and burnishing it, substantially as described."

Infringement is only asserted of the first claim, and, considering the language of the claim and of the specifications, it seems impossible to escape the conclusion that the invention claimed is for the application of heat to the spot to be repaired. And the patentee did not confine himself to the particular apparatus he described. That, he said, was "one form of accomplishing the result." He would have it understood, he said, that he did not confine himself "to any particular form of apparatus for carrying out" his invention, and the independence of his method from any form of apparatus is brought out by

Opinion of the Court.

contrast of what had been done and what he proposed to do as an improvement. What had been done was to take out with a pick or other instrument the surface material around the spot to be repaired, sometimes applying heat to the spot to soften the material, so that it might more easily be removed. And the new method he proposed was to subject the spot to be repaired and surrounding edges to such a degree of heat that the surface asphalt, not only the exact spot to be repaired, but the surrounding material, to a greater or less degree, will be reduced to the soft, pliable state in which it was originally laid. Here we have the comparison of the two methods. The old was to take out the surface material around the spot to be repaired, sometimes applying heat to soften such material. The new method was to apply heat, not only to the exact spot to be repaired, but the surrounding edges. What, then, was the advantage of the new method? The patent tells us. In the old method the depression made by the removal of material was "thoroughly cleaned and given a coat or dressing of tar." The tar acted as a solder, but the joint between the old and the new material was discernible, and often a ridge was formed, and the adhesion of the materials yielded to frost and other causes. The new method dispenses with the tar and its consequences. It substituted the melting of the surrounding edges, producing a union and coalescing of the old and new material, making a better appearing and more lasting repair. If the method and effect of the patent be different from this, we are unable to discern it from the patent or from the testimony. Indeed, there is no other difference established by the testimony. One-of the expert witnesses of the petitioner testified as follows:

"It is further evident that in such use of defendants' device. and in the repair of pavements in part by the use of said device by defendants, the use of tar or any other cement or 'solder' is obviated, that the union between the patch of new material and the old pavement is direct, immediate and complete without the intervention of an interposed body of tar or like material, and that the joint need, therefore, present none of the disadvantages, objections or defects in respect either of appear

Opinion of the Court.

ance or of effectiveness, which distinguished the old tar joint and which are obviated by the method here in controversy.

*

"There are three steps or process elements enumerated in this claim, to wit: First, subjecting the spot to be repaired to heat; second, adding new material;' and third, smoothing and burnishing.' These are all performed in the same order by the defendants. The separate steps, are, moreover, essentially the same in kind in defendant's practice, as set forth in the patent. The heat is applied to the spot to be repaired with a flame blast. The new material added is the same in condition and character; it is not tar or any part tar, but is solely the asphalt composition like that of the old pavement, and in the soft condition and heated state in which said composition is and was originally applied. The smoothing and burnishing is the same step in both cases, being the old and familiar operation performed by means of heated metal tamping and smoothing irons long before used in leveling and smoothing original asphalt pavement surfaces." And he further testified:

"It appears to me to be a feature of the patented method, or a characteristic of the steps of applying the new material, that the new material is placed into direct contact with the old, as if the claim read 'adding new material in direct contact with the old material and smoothing and burnishing it.'"

In other words, the mixing of the old and new material around the edges of the excavation and "adding of new material in direct contact with the old material, smoothing and burnishing it," is the essence of the invention, and so unqualifiedly is this true that a witness of petitioner testified that if the heat which was applied not only melted, but burned the immediate surface and as well "the particles deep down," and the material thus burned raked away clean before new material was applied, the method of the patent would be followed.

As thus described, was there anything in the art which preceded the Perkins method and took from it the claim of originality and invention? The Circuit Court and the Circuit Court of Appeals found that a patent issued to Paul Crochet,

Opinion of the Court.

June 11, 1880, in France, had that effect, and we concur in the finding. The process described in the Crochet patent is for the "Preparation and Recharging of Compressed Asphalt Roadways." The following is the specification of the patent:

"When it was designed to repair or recharge a roadway in asphalt with the means which are now at command, the operator generally delimits with a pick the part which is to be replaced and takes therefrom the asphalt; but it is rare that this operation has not for consequence the starting of the adjacent portions which are sound, swelling them up in such wise that at the end of a little while it is necessary to repair them in their turn.

"To avoid this I have designed a process for repairing and recharging asphalt roads which suppresses such inconveniences. It consists in reheating the part to be mended by means of a movable furnace which the operator shifts about at the surface of the roadway until such portion decrepitates and becomes friable. The upper part of the layer of asphalt and that which has been damaged are taken off by means of an iron scraper armed with small teeth, which perform the office of a rake; said scraper in raising the material forms at the same time upon the part remaining numerous striæ which render the surface wrinkled and augment the adherence of the additional over-thickness which constitutes the recharge.

"The repeated passage of the movable furnace thereon has equally for its effect to vaporize the water and the humidity which are found in the asphalt pavement at the portion to be repaired or recharged.

"After this preparatory operation, the workman spreads a convenient depth of asphalt in powder-like state and stamps it by the ordinary means; because of the softening of the subjacent layer, said layer solders itself perfectly to the new coat, and forms with it a thickness without break in continuity. Such repair and such recharging do not at all impair the neighboring portions.

"It is clearly evident, besides, that the same work of recharg ing can be done over the whole surface of a street instead of being done in spots, and that it is independent of the depth of the asphalt layer.