after declared in the event of a reversal of this decision of the Primary Examiner. On the contrary, if the interference shall not be dissolved until the ex parte question of patentability shall run its full course of appeal, the patent of Greaves will stand in the mean time a menace to the applicant Stone and to the public.

It seems to me to be the better practice to give the ex parte question of priority its legal course of adjudication by permitting the appellants, or either of them, to demand a reconsideration by the Primary Examiner, and from a second adverse decision to appeal to the several appellate tribunals in succession, if necessary, and in the mean time to suspend the interference a reasonable period for that purpose, and to provide for its dissolution at a future day, unless the claim shall be decided to be patentable.

The interference will be suspended until July 1, 1880, unless the decision of the Primary Examiner rejecting the claim for lack of novelty shall be sooner reversed. If the decision shall be reversed before that day, the suspension will thereupon terminate without further order; but if it shall not be reversed, the interference will, without further order, be finally dissolved.

This order is subject to rescission or modification by the Commissioner for good cause shown.

SLADE. BLAIR.

Decided January 15, 1880.

17 O. G., 261.

1. An assertion by a witness who is a party to an interference that he "invented" the device in question at a time designated is of little weight as against substantive facts duly established tending to disprove or qualify such assertion.

2. A conception which takes no form of acts or words, but is a mere mental abstraction, is not the conception with which the law permits the inventor to connect his reduction to practice by proof of intermediate diligence so as to carry back to it the date of his invention.

3. The completed specification of Charles W. Siemens, dated February 21, 1868, in English Letters Patent No. 2,395; the English patent of Josiah M. Heath, No. 10,798, August, 1845, and the American patent of Emile and Pierre E. Martin, No. 72,061, December 10, 1867, are all valid references in anticipation of a claim for the use of iron sponge for the decarburization of cast-iron in the manufacture of steel by the Siemens-Martin process.

4. The use of iron sponge for the decarburization of cast-iron in a process for the manufacture of steel, which consists in mixing with the molten cast-iron sponge enough to dilute the carbon in the mass to the exact proportion required for steel, is analogous to the use of sponge in a process which consists in adding to the molten cast-iron sponge enough to carry the dilution of the carbon in the mass beyond the point required for steel, and subsequently restoring the proportion by the addition of cast-iron; so that there is no patentable difference between these two uses of iron sponge.

5. A claim for "the use of iron sponge for the decarburization of the bath in the manufacture of steel by the Siemens-Martin process" is generic, and a specific claim for the use in that process of iron sponge of a high standard of purity must be subordinate to such generic claim.

APPEAL from the Examiners-in-Chief.

USE OF IRON SPONGE IN THE MANUFACTURE OF STEEL.

PATENT of Thomas S. Blair granted May 31, 1872. Application of Frederick G. Slade filed July 13, 1872.

Messrs. Bakewell & Kerr for Blair.

Mr. C. F. Blake for Slade.

PAINE, Commissioner:

The subject of the issue was defined by the Primary Examiner to be "the use of sponge with the Siemens-Martin process," and was adjudged by him to be embraced in the fifth claim of Blair's patent and in the single claim of Slade's application.

Blair's fifth claim is for

The manufacture of cast-steel from iron sponge by melting the iron sponge in a bath of molten pig metal, the iron sponge being directly charged in a loose cold state, substantially as herein before described.

Slade's claim is in these words:

I claim as my invention the use of iron sponge for the decarburization of the bath in the manufacture of steel by the Siemens-Martin process, substantially as set forth. The Siemens-Martin process of manufacturing steel, which is Martin's process carried on in the furnace of Siemens, embraces four branches, including the preparation of the decarburizing agent: (1) melting on the open hearth of a reverberatory furnace pig-iron or cast-iron containing more carbon than is required for steel; (2) preparing iron free from carbon, as wrought-iron, scrap-iron, puddled blooms, or ore, treated or raw; (3) mixing with the molten pig-iron or cast-iron a sufficient quantity of iron free from carbon to dilute the carbon of the mass below the proportion contained in steel, and (4) adding cast-iron rich in carbon until the carbon in the mass is brought back to the exact proportion required for steel.

Blair claims, in argument, the use of iron sponge of a high degree of purity for the dilution of the carbon contained in pig-iron or cast-iron as an improvement on the Siemens-Martin process; but Slade, in argument, claims the use of iron sponge of any degree of purity as an improvement on this process.

The question whether the subject-matter of the issue, which is "the use of sponge in the Siemens-Martin process," is embraced in the record claims of these parties, so that an interference actually exists between them, will be more conveniently considered after other questions arising in the case shall have been disposed of.

Iron sponge, which is iron freed from oxygen, carbon, and other impurities without fusion, is more or less pure according to the extent to which the expulsion of those foreign substances is carried. No one has made or used, or claims to have made or used, absolutely pure iron sponge.

If Slade's assertion that he is the first to use iron sponge, pure or impure, in the Siemens-Martin process is true, and if its use involves patentable invention, he is entitled to a patent subordinate to the patents of those upon whose inventions his process may be an improvement. If Blair's claim to have been the first to use iron sponge of his standard of purity in the manufacture of steel by the open-hearth process is well founded, and if the use of such sponge involves patentable invention, he is entitled to a patent, subject to the rights of all the others of whose devices his process is an improvement.

What is the date of Slade's invention?

He testifies as follows:

In 1867, at the Paris Exposition, in France, I saw specimens of steel made by the Martin process, and was sent to the works of Messrs. Martin to learn the practical operation of the process, in order to establish it at the works of Messrs. Cooper, Hewitt & Co., of Trenton, New Jersey. Having become familiar with the process, I learned that Mr. Cooper, of this firm, had for many years been engaged in experiments in reference to the manufacture of sponge, and it at once occurred to me that this metal or substance would be peculiarly suited to the manufacture of steel by this process. On my return to America, in 1867, while awaiting the issue of Martin's patent I was engaged in making drawings for a furnace for the manufacture of sponge to be used in this process. During the year 1868 I was engaged in building the first furnace for the manufacture of steel. This furnace was started on the 9th of December, 1868. In January, 1869, we purchased some sponge made in New York State, from Lake Champlain ores, and made steel successfully in the manner claimed in my application. Since that time I have been engaged in constructing, at Trenton, a furnace for the manufacture of sponge, in accordance with plans furnished by Mr. Cooper.

Now, this testimony would seem to imply that the idea of using sponge in the process under consideration occurred to him at the works of the Messrs. Martin, in the summer of 1867. In his argument before the Examiner of Interferences, Slade asserts that

He was sent by Mr. Hewitt, of Cooper, Hewitt & Co., of Trenton, New Jersey, to the works of the Messrs. Martin to acquire a practical knowledge of the Martin process, with a view to its introduction into use at Trenton, New Jersey; and while there, and having heard that Mr. Edward Cooper had manufactured sponge, it struck him that metallic sponge would be well adapted to the purpose instead of wroughtiron.

But on cross-examination Slade says:

Cross-Q. 16. In connection with learning "that Mr. Cooper had for many years been engaged in experiments in reference to the manufacture of sponge," did you acquire at that time any additional knowledge as to this sponge or its manufacture?-A. I acquired a knowledge of the general method in which it was made, but nothing of any peculiar properties of the sponge itself.

Cross-Q. 17. Please state what knowledge you then acquired, and from whom.-A. I don't remember exactly, but my impression is that it was Mr. Cooper first described to me his process for making sponge, and that it consisted in passing a current of carbonic-oxide gas, previously heated, through the mass of ore.

Cross-Q. 18. When did you learn this from Mr. Cooper?-A. In December, 1867. Cross-Q. 19. Was that before or after your return to this country?—A. After; immediately after.

Cross-Q. 24. When was it, now, that the idea occurred to you of using iron sponge in the manufacture of steel by the Martin process; was it before or after you visited Martins' works; before or after you learned of Cooper's experiments, and before or after your return to this country?—A. It was after visiting Martins' works. As soon as I became familiar with the process it was evident that sponge would be the most Suitable material for use in this process; but it was not until I learned of Mr. Cooper's experiments that I supposed we should be able to obtain sponge for such use. I don't remember when I first heard of Mr. Cooper's experiments, and hence cannot say whether it was before or after my return from Europe.

There is on file an ex parte affidavit made by Slade, April 11, 1873, in which he says:

The process was invented by me in 1867, and as soon thereafter as suitable means could be procured it was practically and successfully tested in January, 1869.

If this ex parte affidavit were legal proof in the case, the assertion that the process" was invented" by him in 1867, which is a proposition of mingled law and fact, would necessarily be of little weight in presence of the details of fact furnished by the deposition. A mere naked assertion of invention is of small importance compared with a statement of the facts constituting the alleged invention.

The only fact showing, or tending to show, a conception by Slade in a legal sense, prior to 1869, established by the testimony of Slade, or by any other testimony, seems to be the fact alleged by Slade that at some time in 1867 "it occurred" to him that sponge would be peculiarly suitable to the manufacture of steel by the Siemens-Martin process. Neither Slade nor any other witness testifies that Slade ever communicated this idea to any other person before 1869. He does testify that on his return to America in December, 1867, while awaiting the issue of the Martin patent, he was engaged in making drawings for a furnace for the manufacture of sponge to be used in this process; but he does not say that this was in pursuance of any suggestion of his own.

A. S. Hewitt, in an ex parte affidavit filed by Slade, and dated April 4, 1876, says:

After returning to the United States I directed Mr. Slade, who was employed in the works of the New Jersey Steel and Iron Company, owned by Cooper & Hewitt, to test the use of sponge instead of wrought-iron or ore in the Martin process, which he did early in 1869, and reported to me that there would be no difficulty in using iron sponge in that process in the manufacture of steel.

How long after Hewitt's return he gave those directions it does not appear.

Edward Cooper, in his affidavit of the same date, also filed by Slade, says:

In January, 1869, the said Slade, with my knowledge and advice or direction, made an experiment in the manufacture of steel, which experiment is described in the testimony of the said Slade given in this case.

And Slade himself testifies as follows:

Q. 9. Was Mr. Edward Cooper, of the firm of Cooper, Hewitt & Co., of Trenton, acquainted with your earlier experiments in working at the process at issue?—A. He did not witness those experiments, but I think he was aware that I had made them; but I do not know positively.

Now, suppose that this mental conception occurred to Slade in December of 1867, or even in the summer of that year. The conception is not shown to have taken any form of acts or words-to have been anything else than a mere mental abstraction-before January, 1869. It is not with such a conception that the law permits the inventor to connect his reduction to practice by proof of intermediate diligence, so as to carry back to it the date of his completed invention. Slade's invention must take date in January, 1869. The earliest date which can be given to Blair's invention is that of his return from Europe to the United States in May, 1871.

Blair insists that Slade's broad generic claim for the use of iron sponge, without regard to its purity, is anticipated by the English patent of Charles W. Siemens, No. 2,395, 1867; by the English patent of Josiah M. Heath, No. 10,798, 1845, and by the American patent of Emile and Pierre Martin, No. 72,061, December, 1867.

The completed specification of Charles W. Siemens, dated February 21, 1868, in Letters Patent No. 2,395, shows the process of manufacturing steel in four branches, namely: (1) melting cast-iron on the open hearth of a furnace; (2) preparing spongy iron; (3) mixing spongy iron with molten cast-iron, and (4) adding cast-iron. This completed specification contains the following statements:

*

In commencing operations I generally form a metallic bath of cast-iron, introduced through side doors of the furnace, which greatly facilitates the liquefaction of the metallic spongy iron formed in the hoppers. With the ore, scrap iron or steel, such as engineers' turnings, &c., or cast-iron in a more or less divided state, may be charged into the hoppers, to be also absorbed in the metallic bath, or wrought metal may be fed in through separate side doors or hoppers. At the end of each operation, whatever may be the ingredients employed, before tapping the metal I generally add a certain proportion of rich spiegeleisen or metallic manganese to the bath in order to improve the quality of the steel. By the conjoint action of the reducing agents and of the heat applied externally to the hoppers the iron ore is reduced to spongy iron, which, in coming into contact with the metallic bath, is readily absorbed and dissolved therein, the earthy constituents rising to the surface of the bath in the form of slag or scoria. In proportion as the spongy iron produced by reduction in the hoppers is dissolved fresh material is added at the top, and this, in gradually descending in the hoppers, is in its turn reduced and dissolved. This having been effected, from five to eight per cent. of ferro-manganese or spiegeleisen is charged in at the side doors, and the bath is stirred gently as soon as it is melted, after which the bath is ready for tapping.

And he claims:

1. Making cast-steel upon the open hearth of a furnace by effecting simultaneously the reduction of iron ores in vertical heated hoppers and the dissolution of the reduced metal without exposing it to the flame in the metallic bath provided in the furnace, substantially as hereinbefore described with reference to Sheet 1 of the accompanying drawings.