bination not less than A and B, and so will E and F. It is not necessary that the sub-combination of C and D, in order to be patentable, should embrace A and B, parts nearest to the power. If that were so, no sub-combination actuated by steam-power would be complete or patentable unless the chain of the combination reached back through the pulleys, shaft, engine, and boiler to the fire itself.

The appellant may be correct in his legal proposition that he has a right to claim a "sub-train of mechanism," and also a combination of its elements with parts of the old train connected in action therewith; but it still remains to determine whether this proposition is applicable to the case, and, if applicable, is decisive; and the questions whether the sub-combinations are complete and patentable sub-combinations are appealable to the Examiners-in-Chief, whatever legal propositions may or may not be involved in their solution.

Upon the final decision of the Examiners-in-Chief, or of the Commissioner on appeal, will depend the disposition of so much of the question concerning the amendment of the drawing as relates to the additional parts adjudged by the Examiner to be necessary to the sub-combinations. The requirement that certain parts shall be represented by dotted lines will be complied with.

The decision of the Primary Examiner is affirmed.

FARMER v. BRUSH.

Decided January 6, 1880.

17 O. G., 150.

1. A conception which is a mere mental abstraction, not connected with acts or words, is not the conception with which the law permits an 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.

2. The race of diligence commences with the second conception and ends with the reduction to practice by the inventor first to conceive the device. Neither public use nor an application for a patent is necessary to the completion of the invention. 3. If the inventor first to conceive effects his reduction to practice before he files his application or introduces the invention to public use, the interval between the reduction to practice and the filing of the application or the introduction of the device to public use is not embraced in the period covered by the so-called race of diligence

4. While lack of diligence in filing an application for a patent or in communicating the completed invention to the public may enter as a vital element into the question whether the completed invention has been abandoned or forgotten, it cannot operate er post facto to undo the consuminated work of completing the inven tion.

5. If an inventor abandons or forgets his invention before its public use, it may become the property of a subsequent inventor. Abandonment, in the sense in which the term is here used, is the cessation of all effort to confer upon the public the benefit of the invention. Such abandonment may be voluntary and absolute, as when

the invention is deliberately thrown aside with a purpose never to resume it; but it may also occur when the invention is thrown aside, not with a purpose never to resume it, but without any purpose to resume it.

6. The question of abandonment is not one of mere mental operation. Proof of a mental purpose to give the public at some future time the benefit of the completed invention, unaccompanied by corresponding acts or words, will not necessarily overcome the presumption raised by acts of a party tending to show a purpose to abandon the invention.

7. A mere delay of two years in the application for a patent is not evidence of abandonment; but neglect to confer the benefits of the invention upon the public, whether it is or is not accompanied by neglect to apply for a patent, is evidence of abandonment.

8. An inventor may abandon or forget his invention, and then resume or recall it before another makes the invention; but his rights will not, in such case, relate back to his original invention, so as to give him the benefit of its date as against rival inventors.

APPEAL from the Examiner-in-Chief.

METAL-COATED CARBONS FOR ELECTRIC LIGHTS.

PATENT of Charles E. Brush granted October 23, 1877. Application of Moses G. Farmer filed June 21, 1878.

Messrs. Coburn & Thacher for Farmer.
Messrs. Leggett & Leggett for Brush.

PAINE, Commissioner :

Brush testifies that he conceived the invention in 1866 or 1867. But the conception took no concrete form at that time, and a conception which is a mere mental abstraction, not connected with acts or words, is not a conception in the sense of the law. Brush's invention is correctly adjudged by the Examiners-in-Chief to have been made in April, 1877.

Farmer's invention is adjudged by the Examiner of Interferences to have been reduced to practice early in the year 1876, but to have been forfeited by subsequent want of diligence in conferring upon the public the benefit of the invention. The Examiners-in-Chief, on the contrary, did not find it to have been reduced to practice by Farmer in 1876, or at any other time. If the Examiners-in-Chief are right in their conclusion that Farmer never reduced the invention to practice, judgment must, of course, be rendered in favor of Brush. But suppose, on the other hand, that the Examiner of Interferences is correct in his conclusion that Farmer reduced the invention to practice early in the year 1876. The question then arises whether Farmer has, in any way, lost or forfeited his right to the patent.

The law accords a patent to the first and original inventor. It is the reduction to practice, and not the conception alone, which constitutes completed invention. But suppose that A forms what is known to the law as a conception of the invention, and at a subsequent date reduces

it to practice, and that, in the mean time, B both conceives the invention and reduces it to practice. The question whether A or B is entitled to the patent depends on the further question whether, as between A and B, the invention of A is to take the date of his conception or the date of his reduction to practice. This question is not explicitly answered by the terms of the statute. But the answer furnished by judicial interpretation of the statute is that if A connects his reduction to practice with his conception, by showing due diligence in the prosecution of the invention from the date of his conception to the date of his reduction to practice, his invention takes the former date and he is entitled to the patent, but otherwise it is to be granted to B. This shows at once the origin and the nature of the so-called race of diligence. It commences with the second conception and it ends with the reduction to practice by the inventor first to conceive the device. Neither public use nor an application for a patent is necessary to the completion of the invention.

If the inventor first to conceive effects his reduction to practice before he files his application or introduces the invention to public use, the interval between the reduction to practice and the filing of the application or the introduction of the device to public use is not embraced in the period covered by the so-called race of diligence. If, however, the filing of the application or the introduction to the public use is relied upon as the act, or as the evidence, of reduction to practice, another question is presented which it is not now material to consider.

If A, having conceived the invention before B, prosecutes it with due diligence and reduces it to practice after B has reduced it to practice, he will establish his title to the patent under the law. When his reduction to practice is completed his invention is completed, without the filing of his application, and he becomes, in the sense of the law as interpreted by the courts, an original and first inventor. Thenceforth the question will be, not whether he shall, by the exercise of due diligence in filing an application or introducing to public use, complete his invention and secure his right to the patent, but whether he shall, in any way, lose the title to a patent already acquired by the completion of the invention in accordance with the requirements of the law.

While lack of diligence in filing an application for a patent, or in communicating the completed invention to the public, may enter as a vital element into the question whether the completed invention has or has not been abandoned or forgotten, it cannot operate ex post facto to undo the consummated work of completing the invention.

If an inventor abandons or forgets his invention before its public use, it may become the property of a subsequent inventor. Abandonment, in the sense in which the term is here used, is the cessation of all effort to furnish the invention for public use. Such abandonment may be voluntary and absolute, as when the invention is deliberately thrown aside with a purpose never to resume it; but it also may occur when the invention is thrown aside, not with a purpose never to resume it. If it is

merely laid aside temporarily, with an intention to resume it, there is no abandonment. But the question of abandonment in such case is not one of mere mental operation. A mere mental purpose or intention to give the public at some future time the benefit of a completed invention, unaccompanied by any corresponding acts or words, amounts to nothing; and the presumption raised by acts of the party of a purpose to abandon will not be overcome by his testimony that he mentally intended not to abandon it. Such testimony will be construed in connection with the acts of the party; and although it may throw light upon such acts, and, taken in connection with them, may determine their meaning and effect, yet it will not be always decisive when contradictory, rather than explanatory, of such acts.

Now, a mere delay of two years in the application for a patent is not evidence of abandonment; but neglect to confer the benefits of the invention upon the public, whether it is or is not accompanied by neglect to apply for a patent, is evidence of abandonment. The inventor may voluntarily keep his invention secret as long as he sees fit to do so, provided he applies for a patent before another invents the device. He may abandon or forget his invention, provided he resumes or recalls it before another makes the invention. But his rights do not, in either case, relate back through the intermediate "vacuum" to the original invention, so as to give him the benefit of its date as against a rival inventor.

The questions, then, are whether Farmer completed his invention in 1876, and whether, if he did, he had abandoned it when Brush obtained his patent. It will be convenient to consider the second of these questions first.

Farmer did not use the invention, either in public or in private, between the early part of the year 1876 and the latter part of the year 1878; nor did he, during that period of time, make any effort to introduce his invention to the public. The presumption of abandonment raised by these unexplained facts would not be easily overcome by evidence of a mere mental purpose to retain the invention and to confer its benefits upon the public. But there is no proof establishing or tending to establish the existence of any such mental purpose. The presumption raised by the facts is absolutely uncontradicted. Farmer must therefore be adjudged to have abandoned the invention, if he did in fact complete it, in 1876.

But did he complete it in 1876? The object of this invention, which was to restrict the consumption of the carbon to the point of illumination by the use of the metallic envelope covering its entire surface to that point and presenting comparatively slight resistance to the electric current, would seem to have been as perfectly accomplished by the use of his carbon B as by the use of any carbon exhibited in the case. This carbon certainly was coated with copper beyond the point to which it was consumed, and a part of the copper envelope was itself burned by the electric current. Whether that part of the carbon which was not origi

nally covered with copper was broken off, or was burned off by the electric current in making the comparative test of the resistance of plated and unplated carbons, the fact remains that this carbon B, in its present condition, exhibits a metallic conducting-surface extending to the point of combustion as operative for the purpose of restricting the consumption of the carbon to the point of illumination as that of any exhibit on file in the case. But it is said that the thickness of the envelope resulted in an excessive contribution of burned copper to and a consequent discoloration of the light itself, and that this fact invalidated Farmer's reduction to practice. Now, if the envelope used by Farmer had successfully restricted the combustion of the carbon to its extremity, but had, at the same time, extinguished the light, it certainly would not have been a reduction to practice amounting to a complete invention. On the other hand, if the discoloration of the light by the burned copper had been merely a defect for which common sense or ordinary skill, without inventive genius, would have suggested a remedy, it would not have invalidated his reduction to practice. That the defect in this case lay nearer to the former than to the latter of these exterior limits is to my mind by no means clear.

I do not find it easy to concur in the conclusion of the Examiners-inChief that Farmer did not in fact invent the device in controversy before Brush. But inasmuch as the invention, if completed by Farmer, was also abandoned by him, it is not important to decide whether the Examiner of Interferences or the Examiners-in-Chief were right on this point.

On the ground of abandonment by Farmer, priority is awarded pro forma to Brush.

HEDGES V. DANIELS.

Decided January 8, 1880.

17 O. G., 152.

1. Neither under the old rules nor now can the Examiner of Interferences dissolve an interference in view of ex parte affidavits setting forth public use of an invention as a bar to the application of contesting parties.

2. Rule 75 provides for the rejection of an application by the Primary Examiner on the grounds of public use or sale, and permits him to consider affidavits or depositions supporting or traversing such an objection.

3. Rule 120 provides that, upon the attention of the Commissioner being called by the Examiner of Interferences or the Examiners-in-Chief to a statutory bar to the grant of a patent to either party, he may suspend the interference and remand the case to the Primary Examiner for the consideration of such objection. APPEAL from the Examiner of Interferences.

PADLOCKS.

APPLICATION of J. J. Hedges filed July 7, 1879. Application of H. H. Daniels filed April 14, 1879.