In the present case a patent wss issued four years ago; as we have already seen, no person other than the patentees appears entitled to be regarded as the first inventor; the application for the patent was made in due time after the invention was reduced to practice; and a manufacture under the patent has been going on during the entire period of its existence. The question presented, then, is whether a patent under which large vested interests have grown up shall be treated as null and void, and at a time when by reason of the long-continued public use of the invention it would be impossible to correct the error in the form of the application, if any error has, in fact, been committed. It is not a question whether the grant of a patent shall be refused on the ground of a misjoinder of parties. I am fully convinced that the testimony does not warrant a judgment which, if it could in any way be made operative against the parties, would work them such hardship.

But, in fact, a different decision of this question would be of no direct practical benefit to the applicant. It would neither cancel the patent of his rivals, nor would it entitle him to receive one upon which to bring suit against them; for the evidence, as already stated, shows that, whatever view may be taken of the validity of the Russell and Miller patent, Wheeler, not being the first inventor, caunot legally become a patentee. Question arises in this case, on behalf of the patentees, whether, under the dectrine laid down in Monce vs. Adams, Patent-Office Gazette, 1872, p. 2, Wheeler, even if the first inventor, has not forfeited his rights through laches, it appearing that he delayed his application for a patent from the summer of 1866, when he had the invention fully reduced to practice, till October, 1868, more than six months after a patent had issued to his rivals, who came to the office without unreasonable delay after they had reduced the invention to practice and brought it into satisfactory form. It further appears that Wheeler, being rejected 1 October 17, 1868, did nothing further in the prosecution of his application until the 7th of January, 1871, reviving it on the very last day allowed him under the special provisions of section 35 of the patent act. It is rendered unnecessary, however, by the view taken upon the other questions involved in the interference, to enter upon the discussion of this one.

It is equally unnecessary to decide whether the use made by Wheeler of his invention in the State trial at Auburn in 1866, more than two years prior to the filing of his application, was such a public use as, under section 24 of the patent law, would of itself bar his right to a patent. It is probable that the machine was put into this public trial more for the purpose of testing its relative merits than its abstract utility. It may well be presumed that the utility of the invention had been demonstrated to the satisfaction of the inventor by previous experiments, and that the object of the public trial was to demonstrate to the public that the machine possessed points of superiority over other machines. Upon this theory it may well be questioned whether the public competi

tive trial was not a "public use" of the invention in the sense in which the term is used in the section named. But, this question aside, the decision of the Examiners-in-Chief must be sustained, and Russell and Miller are adjudged the prior inventors.

JAMES D. STURGES.-EX PARTE.

APPEAL FROM THE EXAMINERS-IN-CHIEF ON AN APPLICATION FOR LETTERS PATENT FOR A COOLER FOR LIQUIDS.

(Decided February 29, 1872.)

Patentable claims-Practice in examination of claims.

A new combination is patentable, even if all the elements of it are old.

It is no objection to a claim that it includes only a part of the mechanism which the applicant proposes himself to use, provided the part thus included is capable of use. ful operation independently of the parts omitted.

It is no good ground for rejecting a claim that it is sought, not for the purpose of covering the specific mechanism which the applicant proposes to construct, but for the purpose of protecting him against the use by other parties of some particular part or parts of such mechanism.

This fact may be a good reason for the exercise of more than ordinary care in conducting the inquiry into the alleged novelty of the subject-matter of such claim.

DUNCAN, Acting Commissioner:

Applicant's invention is designed for the cooling of liquids or semifluid substances by taking advantage of the well-known fact that rapid evaporation is attended by a loss of heat in the surface from which the evaporation takes place. His apparatus consists of two concentric tubes, the inner one, through which the liquid to be cooled is passed, being surrounded with an absorbent jacket, which is kept moistened by a small supply-pipe placed immediately above it, and from which the water or other fluid to be evaporated is fed through numerous small apertures uniformly throughout its entire length. A blast of air is forced through the annular space between the two concentric tubes; and, for the purpose of obtaining the maximum exposure of the liquid to be cooled to the influence of the evaporation which is taking place without, the inner tube is provided with a core, which spreads the liquid into a thin sheet in immediate contact with its inner surface.

Under the decision of the Examiners-in-Chief a claim has already been allowed for the combination of the liquid-carrying tube, the absorbent jacket, the perforated supply-tube, and the inclosing air-case or outer tube. In addition to this, applicant asks for a claim for the combination of the inner tube, the absorbent jacket, and the perforated feedingtube, the surrounding air-case not being named. This claim now'stands rejected upon reference to the patents of D. E. Somes, May 10, 1870, for improvements in apparatus and process for refrigerating, preserving,

and ventilating; and March 29, 1870, for improvement in cooling air and liquids; and the patent of E. Bigelow, October 18, 1870, for an improvement in liquid-coolers.

In the Bigelow patent the liquid is passed in a thin annular sheet (a core being used to bring it into this form) through a tube which, instead of being surrounded with a fibrous jacket, is buried in ice. Somes, in his patents, shows, among other things, the use of a wetted fibrous material upon the roof of a refrigerating-house or apartment, and upon the roof of a railway-car, the absorbent covering being in both cases kept moist by a small supply-pipe which runs longitudinally along the ridge of the roof, and is perforated so as deliver the water equally on the two sides and uniformly throughout its entire length.

It is plain that the Bigelow patent by itself is not a sufficient reference. There seems also to be a radical difference between the conditions under which Somes and the applicant apply a common and wellknown principle. The one seeks, by means of the reduction of temperature caused by the evaporation of liquids, to cool a body of air confined within a chamber, and has in view some ulterior purpose beyond the mere cooling of the air-such, for instance, as the freezing of liquids, the preserving of meats and fruits, and the like. The other seeks simply to reduce the temperature of a body of liquid, which, for this pur pose, must be made to pass in a continuous stream along and over surface which is previously cooled by the evaporation. In the one caɛ. the substance directly acted upon is air; in the other a liquid. In the one case a closed chamber is used; in the other an open tube. In the one case the air to be cooled is only a medium for affecting the temperature of some other body or substance surrounded by it; in the other the primary object is to cool the liquid itself which is directly acted on.

Neither of the references, then, taken alone, seems to justify a refusal of the claim asked for. It is only by selecting elements from each of the existing inventions that applicant's invention is produced. From Bigelow he has borrowed the idea of the externally-cooled tube, through which the liquid is to be passed; from Somes the means of effecting the necessary reduction of temperature in this tube. A legitimate combination is thus produced; and a new combination is patentable even if all the elements of it are old.

Neither is it to be objected to the claim that it omits the element of the inclosing air-tube, while in the specification there is no intimation that the applicant intends in practice to use his apparatus, except as it is provided with such outer case.

Where a claim is asked for, not so much to protect the specific construction which the inventor proposes to adopt as to enable him to lay under contribution other constructions embodying a part only of the principles upon which his aggregate mechanism is built up, this may furnish a reason for an exceptionally careful inquiry into the alleged novelty of the subject-matter of such claim before favorable action upon

it; but it cannot be held to constitute, in itself, good ground for rejection of the claim. Where a part of a compound mechanism is capable of useful operation in itself, the inventor has a right to protect himself against the use of such portion by other parties, even though he does not himself propose to use that particular part except in connection with all the others.

In the present case it is manifest that the combination to which the appeal relates is capable of useful operation independently of the airtube, though it is presumable that a higher effect would be produced if the blast of air should be controlled by the presence of the tube. While, therefore, the applicant designs, probably, to use only the mode which he conceives to be the best, he naturally and rightly seeks to bring his patent into such form as to prevent the use by others of the inferior mode as well as the best.

The decision of the Examiners-in-Chief is overruled, and the claim allowed.

HARRIET L. LOW, ADMINISTRATRIX.

Extension.

APPLICATION FOR THE EXTENSION OF LETTERS PATENT GRANTED TO HENRY H. LOW, MARCH 6, 1858, FOR AN IMPROVEMENT IN SAWING-MACHINES.

(Decided March 2, 1872.)

Practice where the original patent has been reissued.

Where a patentee assigns his entire interest in his patent for the original term, and the assignee without the concurrence of the patentee surrenders the original patent and secures a reissue, the patentee may have certificate of extension attached to the original patent.

LEGGETT, Commissioner:

The invention to which this application relates is an improvement on sawing-machines. The claim is very narrow, disclaiming all the parts of the machine, and claiming only the combination in the definite form stated. The examiner reports that this combination was new and patentable at the time the patent was issued, and that the proof shows the same to be of considerable value to the public. The statement of accounts is not very full or definite; but this is explained partly by the death of the patentee, and his books not showing minutely the expenditures on account of the patent; but enough is shown to satisfy the Office that the net receipts have been very small, and much less than the value of the invention.

An argument has been filed in opposition to the extension, based

chiefly upon the fact that the application is for the extension of the original patent, while the original patent was surrendered and reissued March 6, 1866, and again reissued April 2, 1867. In the application for extension no allusion whatever is made to these reissues. They are ignored as completely as if they had never been in existence.

The remonstrant holds that, when the original patent was surrendered and reissued, it ceased to exist, and cannot now be revived by extension. This doctrine would be just and applicable provided the patentee had joined in either application for reissue; but the records of the Office show that he assigned his entire interest in the original term of the patent to one C. S. Burt, and that said Burt, as assignee, secured the re■ issues without joining with him, the patentee; and there is no evidence in the Office that the patentee or administratrix had any knowledge whatever of the reissue. Under such circumstances it would be a manifest and unnecessary hardship to require the patentee to apply for the extension of the reissue, and then compel him to incur the expense and risk of another reissue in case he preferred the original form of the patent. In this case the patentee assigned only the original term of the patent, reserving to himself, under the law, the exclusive right to the extended term; and it would be an anomaly in law if the assignee could render the extended term worthless to the inventor by obtaining a worthless reissue just before the expiration of the original term; yet such might be the case if the remonstrant's doctrine is law.

But it is not necessary to further discuss this matter, as the question has been adjudicated by the courts. In the case of Potter vs. Brauns dorf, 7 Blatch., 110, Justice Blatchford says: "Where a patentee, having secured his invention by a patent, with a specification in such form as he regards to be most proper, assigns the entire patent for the original term only, reserving his right under the 18th section of the act of 1836 to apply for and obtain an extension, it ought not to be and it is not in the power of the assignee, by surrendering the patent and obtaining a reissue of it on a specification not signed, assented to, or adopted by the patentee, and which perhaps the patentee may regard as rendering the reissued patent invalid, or as securing, by new and different claims, rights of little value, to effect, without his consent, the statutory right conferred on the patentee to apply for and obtain an extension of the only patent which he has ever adopted or assented to."

The extension is granted, and the certificate will be attached to the original patent; or, if the original patent is lost, to a certified copy of the same.