after making the foregoing statement, delivered the opinion of the court.
As the decree will be reversed for other reasons, we deem it unnecessary here to agitate the first and second questions.
i. The respective experts agree in defining a duster as that which sweeps dust away from a surface, and a renovator as that which restores to freshness throughout; and the distinction is justified by the lexicographers. Nation classified his device as a “duster,” and stated that his invention “relates to improvements in mechanism for cleaning carpets, velvets, furs, and goods of any kind having a nap surface, and will be found specially useful in dusting upholstered goods, such as car seats.” Referring to the drawing, the specifica*766tion says: “B is an expanded nozzle or head terminating the outer end of the tube A, and is provided with the transverse opening, b, on its under side, arranged so as to give a direct downward course to the stream of air.” Thus the air comes “violently into contact with the nap of the goods to be cleaned.” “The direction of the air is shown by the arrows” in the drawing. The hood, C, is made “to envelop the nozzle on all sides, but so arranged as not to interfere with the free passage of the dust-laden air as it leaves the goods” and is conducted into the strainer, “cloth sack, D.” Looking to the drawing and specification, it seems clear that Nation had in mind a mechanism for dusting nap surfaces, consisting of an expanded nozzle through whose orifice, held above the surface, a blast of compressed air could be directed down upon the nap of the goods to be cleaned; a hood that completely enveloped the nozzle on all sides, except that, to enable the air blast from the inclosed nozzle to be thrown down against the nap, an opening was made in the bottom of the hood, directly opposite the orifice of the nozzle, through which opening in the bottom of the hood the air blast could reach the goods to be cleaned; and a strainer to release the air and retain the dust. And the claims, as we read them, do not purport to cover any broader invention. The only difference between the two claims is that the general strainer of claim i is replaced by the specific cloth bag of claim' 2. Both claims describe an essential element as being “a hood enveloping the nozzle and having, an opening opposite the outlet in the nozzle through which the compressed air may be brought into contact with the goods to be cleaned.” That is, the hood completely envelops the nozzle on all sides, except that, to enable the air blast from the inclosed nozzle to be thrown down against the nap, an opening is made in the bottom of the hood, directly opposite the orifice of the nozzle, through which opening in the bottom of the hood the. air blast may reach the goods to be cleaned.
Thurman’s patents refer to his device as a carpet renovator. It is-designed to renovate carpets without removing them from the floor, by directing a blast of compressed air into and through the carpet against the floor at an angle of about 45 degrees, so that the blast rebounds from the floor and passes at the angle of reflection through the carpet and into a hood and strainer. Referring to the drawing of the alleged infringing machine, without detailing other differences in construction between this and the device of the Nation patent, it will be noted that the forward lip of the nozzle’s orifice rests upon the carpet and is in the plane of the machine’s base. Except for convenience of manufacture, the nozzle, instead of being cast in one piece with the hood, might be made separately and bolted to the outer wall of the hood. The air is discharged into and through the carpet outside of the hood, and reaches the hood by reason of being deflected forward at an angle from the floor, and is aided in this course by the •forward lip’s being narrower than the rear lip of the orifice. If the nozzle, the orifice being in the same location relative to the hood as now, were directed rearwardly at an angle of 45 degrees, the air, as the machine moved forward, would escape under the rear lip, up-*767through the carpet, into the room. As it is, the air escapes under the forward lip, up through the carpet, into the hood.
The Thurman machine that was put in evidence by the complainant has the forward lip rounded up so that it is one-sixteenth of an inch above the plane of the base. But the scratches made upon its surface show that the forward lip came in close contact with the carpet. And the complainant’s expert testified that there was no difference in principle between the machine as exhibited and the machine of the drawing. In this conclusion we agree.- Furthermore, the record shows that before the trial the licensor, who is defending this suit, was making his machines so that the forward lip of the orifice was in the plane of the base.
Nation did not disclose that his air blast would penetrate the carpet, strike the floor, and carry up through the carpet the dust on the floor and' in the body of the carpet into the hood. His drawing indicates that the air rebounds from the surface of the goods to be cleaned. But if his device, without material modifications, could be made to do the work of the Thurman machine, it would be by a different mode of operation. If Nation’s air blast penetrates the carpet and rebounds from the floor, it is an incident, and not an essential, of the device’s operation. The air is discharged within the hood. It is true that the height of the orifice above the plane of the base is left by Nation to the builder’s discretion. But it is an essential condition that the orifice be within the ho.od, and opposite (which cannot be in the same plane with) the opening in the base through which the air blast reaches the carpet. In Thurman’s machine it is an essential condition of operation that the air be discharged into and through the carpet outside of the hood. It reaches the hood only after striking the floor and passing up through the carpet.
Unless the wording of Nation’s claims be ignored, we think the Thurman machine, in which the nozzle is not enveloped within the hood, cannot be held to infringe.
It should not be forgotten that the defendant was operating under later patents, and that the art prior to Nation discloses stationary machines for renovating carpets by the use of compressed air, movable machines for dusting carpets by means of air currents in connection with hoods and strainers, and the “open blast nozzle.” In this connection the observation of the Supreme Court in Kokomo Fence Machine Co. v. Kitselman, 189 U. S. 8, 23, 23 Sup. Ct. 521, 47 L. Ed. 689, is pertinent:
“Considering the complainants and Whitney (patentee of defendant’s machine) as- alike having improved on the ‘prior art, the question is whether the specific improvements of the one actionably invaded the domain of the other. The presumption from the grant of the letters patent is that there was a substantial difference between the inventions.”
2. Respecting anticipation it is true that the combination of elements in Nation’s claims is not found in any one prior device. So the citations are not effective to disprove the novelty of Nation’s combination. But the modified Sorensen and McClain machines would be anticipative, and, in our opinion, it did not require invention to produce these modified machines. The modification con*768sisted in substituting the known means for directing an air current from a tank of compressed air upon the goods to be cleaned for the Sorensen and McClain air currents from blowers. This selection among known means, though increasing the degree of efficiency, did not rise to the dignity of independent invention. Mast, Foos & Co. v. Stover Mfg. Co., 177 U. S. 485, 20 Sup. Ct. 708, 44 L. Ed. 856; Lumber Co. v. Perkins, 25 C. C. A. 613, 80 Fed. 528; Kelly v. Clow, 32 C. C. A. 205, 89 Fed. 297, and cases there collated.
3. It is evident that the defendant’s machine cannot be brought within Nation’s claims without giving them the character of a primary invention of means for using compressed air in conjunction with a hood and strainer.
The claims comprise the following elements: (1) An air-pump hose, or a hose connected with a tank of compressed air; (2) a nozzle terminating said hose; (3) means (a valve is the means disclosed) for regulating the escape of air through the nozzle; (4) a hood enveloping the nozzle, and having an opening opposite the outlet in the nozzle, through which (opening) the compressed air may be brought into contact with the goods to be cleaned; (5) a strainer (generic in claim 1, and the specific cloth bag in claim 2).
We have already stated our conclusion that the fourth element, without disregarding the language employed, cannot be accepted as a generic description of a hood. But, if the words could properly be given a generic scope, the claims would be void for want of invention.
The first three elements are an exact description of the old “open blast nozzle.” The fourth and fifth, if treated generically, cover the hood and strainer of the old Lake, Norris, and James patents. Nation, in testifying to his discovery, showed that he was employed for several years by railroad companies in cleaning cars, and used the “open blast nozzle” for that purpose; and that one day, a piece of burlaps having caught on the nozzle, he observed that the dust was strained out as the air passed through the fabric. Certainly, Nation was not, as is now claimed for him, the discoverer “of the function of air under high pressure as an active agent for thorough cleaning when the full benefit of the rebound current of air was obtained.” Nation’s machine brings together means for performing two functions—the function of raising the dust, and the function of catching and holding the dust after it is raised. The two functions are not interactive; not even synchronous; but successive. For discharging the first function Nation employed a blast of compressed air, the use of which for that purpose was old and commonly known. If there is any difference in getting “the full benefit of the rebound,” it lies in favor of the oíd “open blast nozzle”; for, to the extent of the back pressure within the hood and strainer, the blast, discharged within the hood, is retarded in striking and in rebounding from the surface from which the dust is to be raised. For discharging the second function Nation employed (on the present hypothesis of a generic claim) the old hood and strainer of the English patents. Certainly he was not the discoverer of the function of the hood and strainer in catching and holding the dust that has been raised by an *769air current. So the question is whether a claim of primary invention lies for bringing these two old devices into a union in which each performs only its old function. The authorities answer in the negative.
A cupola furnace being old, and it being old to use a cinder-notch in a blast furnace, there was no invention in putting a cinder-notch in a cupola furnace to perform the same function it had in a blast furnace. Vinton v. Hamilton, 104 U. S. 485, on page 492, 26 L. Ed. 807.
Rice did not prove himself an inventor by combining the return flue of a Cornish boiler with the Morey straw-feeding device, which had been used with a common form of return flue. Heald v. Rice, 104 U. S. 737, on page 755, 26 L. Ed. 910.
It did not require invention to couple an engine, which had theretofore been used in turning a windlass, to a capstan, which had theretofore been operated with handspikes. Morris v. McMillin, 112 U. S. 244, 5 Sup. Ct. 218, 28 L. Ed. 702.
A claim based on combining a relief valve with a steam fire engine, when similar relief valves had been used on engines in steamships, was held to lack invention in Blake v. San Francisco, 113 U. S. 679, 5 Sup. Ct. 692, 28 L. Ed. 1070.
A fireplace heater was old. A fuel magazine in a base-burning stove was old. The quality of invention did not inhere in the act of coupling the fuel magazine to the fireplace heater. Thatcher Heating Co. v. Burtis, 121 U. S. 286, on page 294, 7 Sup. Ct. 1034, 30 L. Ed. 942.
To age wine by applying heat being old, there was no invention in heating it with an apparatus that had never before been used for this purpose, but had been used for heating other liquids. Dreyfus v. Searle, 124 U. S. 60, 8 Sup. Ct. 390, 31 L. Ed. 352.
A claim for a process of spreading a known composition on paper to form a surface, in view of other patents showing that it was old to coat paper with other substances, was held void, in Underwood v. Gerber, 149 U. S. 224, 13 Sup. Ct. 854, 37 L. Ed. 710.
In Kokomo Fence Machine Co. v. Kitselman, 189 U. S. 8, 23 Sup. Ct. 521, 47 L. Ed. 689, the question was whether Kitselman had made a primary invention in producing a portable fence machine that was capable of weaving a diamond mesh wire fence in the open field. A prior machine, stationary in a factory, produced diamond mesh wire fabric for fencing. Another prior machine “walked” along in the field as it wove a wire and picket fence. “Kitselman converted the stationary into a portable machine by setting it on end and mounting it on a truck. * * * Whatever its merits, it was not in itself primary invention to mount a machine for making diamond mesh on a truck, and using it in the field as the old machine had been used to make wire and picket fence. The getting up and walking was not new, though the machine may have gone at a better gait and made a better fence.”
And the cases might be multiplied indefinitely.
The decree is reversed, with the direction to dismiss the bill for want of equity.