APPEAL FROM THE CIRCUIT COURT OF THE UNITED STATES FOR THE EASTERN DISTRICT OF PENNSYLVANIA.
MR. JUSTICE BLATCHFORD, after stating the case, delivered the opinion of the court.
As we are of opinion that the decree below must be reversed, because of the invalidity of the reissue, it is unnecessary to consider any other question.
The only claim of the reissue which, it is now contended, was infringed, is the first claim, which reads as follows: "1. A blast furnace with a closed breast, where the slag is discharged through an opening or openings cooled by water, substantially as set forth." Claims 2 to 7, inclusive, of the reissue are substantially in the same language as claims 1 to 6 of the original. Claim 1 in the reissue is entirely new, and it is not contended here that the defendant infringed any of the claims of the original patent, or any claim of the reissue other than claim 1.
It was held by the Circuit Court that, while claim 1 of the reissue was not embraced in the original, the matter claimed by that claim was so embraced; that the language of the original specification clearly described the closed-breast furnace; that a furnace built in accordance with the language of the
original would be necessarily closed-breasted; that the other element of claim 1 of the reissue, "where the slag is discharged through an opening or openings cooled by water," was no less clearly described in the original; that the drawings originally filed showed the same; that claim 1 of the reissue might, therefore, have been embraced in the patent as first issued, or introduced into the reissue without changing the specification; that the change made by the reissue simply expressed the same thing in different terms; that claim 1 of the reissue was, therefore, not an enlargement of the invention; that such additional claim, omitted through inadvertence, accident or mistake, might be secured by means of a reissue, if applied for within a reasonable time; that in this case the application was made a little after the expiration of one year; and that the question whether the omission occurred through inadvertence, accident or mistake, was a question for the Commissioner of Patents.
But we are of opinion that these views cannot prevail in the present case. It is apparent, from the description contained in the specification of the original patent, that Lurmann considered his invention to consist essentially of a removable slag-discharge piece, cast with numerous channels or pipes running through it, formed with a dovetail at its upper end fitted into the bottom of a stationary metallic plate connected with the furnace, and provided with channels or pipes so that water might flow through the slag-discharge piece and plate, conjointly or separately, that they might be cooled while the furnace was in operation. The slag-discharge piece was made removable, and provided with one or more holes, the middle portion of the holes being cylindrical, but each end being conical or flaring. By regulating the flow of water through the slag-discharge piece, its temperature could be lowered sufficiently to allow a coating of slag to choke the discharge-opening, which coating could be melted out by diminishing the flow of water and thus allowing the temperature to rise. The opening could be closed by an iron block when necessary.
The fundamental devices claimed by Lurmann as his improvements were (1) the metal plate C, provided with water
channels; (2) the removable slag-discharge piece provided with water channels; and (3) the method of regulating the discharge of the slag by raising and lowering the temperature of the slag-discharge piece.
The first claim of the original patent claimed a slag-discharge piece provided with a water circulation, connected with a water-cooled plate C, having small hour-glass-shaped discharge openings, and capable of being removed from the furnace when desired. The slag-discharge piece of the second claim was of the same character as that described in the first claim. The third claim was for the shape of the slag-discharge opening, flaring at its ends, and of diminished diameter in the middle. The fourth claim was for the combination of such slag-discharge piece and a series of water channels or pipes. The fifth claim was for the combination of the metallic plate C, with a series of water channels or pipes. The sixth claim was for regulating the discharge of the slag by varying the temperature of the water-cooled slag-discharge piece.
Asmus, in his testimony, states that his reason for obtaining a reissue was to make the meaning of the whole invention as clear as possible; that the reason why he did not apply sooner for the reissue was that, in arranging a number of furnaces, they differed more or less in construction, and he had to adapt his construction according to the circumstances; that this made it necessary to give the construction quite different shapes, retaining always the main points; that experience caused him, in order to prevent mistakes, to find a formula which expressed the spirit of the invention in the clearest way possible, and which flowed plainly from the technical description given in the original patent; and that the ...