delivered the opinion of the court:
This is an appeal from the decision of the Commissioner of Patents denying appellant, Prank Buchanan, certain claims on a patent relating to arc lamp electrodes.
Pour claims of appellant’s application, numbered 1, 4, 5, and 6, were rejected, of which claims 1 and 4 are illustrative:
“1. An electrode for luminous arc electric lamps comprising a metal electric conducting shell, and a dry pulverized compound of rutile, and the evaporated residue of water glass, intimately •commingled, filled within the shell, such shell being of sufficient substance to carry the current to supply a conductive metal at the arc during the consumption of the electrode, and to render the fused end of the conductor conductive when cold, substantially as and for the purpose described.”
“4. A slow-consuming luminous arc light electrode comprising a metallic shell and a filler composed principally of rutile and sodium silicate, substantially as and for the purpose described.”
*519The references upon which appellant’s claims were denied are two German patents and one Austrian patent. The elements entering into the various inventions are tabulated in the brief of counsel for appellant, as follows:
If appears from the above table that appellant refused to he guided by any one of the foreign, patents. lie omits the iron filings called for in botb German patents, bnt omitted in the Austrian patent, and he uses sodium silicate, used in conjunction with the iron filings in the second German patent, but omitted from the first German and the Austrian patents. It is no argument against patentability tlmt appellant’s invention consists of a combination of elements old in the art. Diamond Rubber Co. v. Consolidated Rubber Tire Co. 220 U. S. 428, 55 L. ed. 527, 31 Sup. Ct. Rep. 444. The superiority of the invention in issue is set forth in the application, as follows: “I have found that an electrode constructed as described will give a practically steady, strong, white light, and will last from one and one quarter to twice as long as other luminous arc electrodes operating under the same conditions, and will he more perfectly consumed so that less soot is deposited than that with any other luminous arc electrode.”
It is conceded that the art has not been developed to the point where accurate results may be obtained by reasoning from *520cause to effect. Development depends almost wholly upon experiments. The present case is not one where the advanced step taken by appellant, even by the combination of elements old in the art, belongs in the reahn of mere mechanical improvement obvious to one skilled in the art. This was recognized, and properly so, by the Patent Office in granting the following claims :
“2. An electrode for luminous arc electric lamps comprising an iron shell about twenty-five one-thousandths of an inch thick, and a filler within the shell, consisting of powdered rntile and unevaporative residue of water glass, intimately commingled, said rutile and residue being intimately mixed in substantially the proportions of 12 ponnds of rutile with the unevaporative residue of 1 qnart of water glass, substantially as and for the purpose specified.
“3. The herein-described process of making electrodes for luminous arc electric lamps consisting in mixing pulverized rutile and water glass in substantially the proportions herein set forth, into a plastic mass, evaporating the water of the moist mass, pulverizing the dxy product, and filling the same into a metallic tube, substantially as and for the purpose set forth.”
We think, considering the experimental status of this developing art, that there is no just reason for confining appellant to the narrow limits of the claims granted. True, in his specification, he avers that the best results have been obtained from the combination of the elemeixts in the proportions set forth in the claims allowed, but that proportion is adopted as preferable only at the attained stage of experimental development. His combination of elements, even where the preferred preportions are not used, nevertheless produces a new result. Appellant should be permitted broadly to prefit by possible improvements to be attained in the further developxnent of his invention within the limits of the present specification. Patentability being conceded by the allowance of the narrow claims, we are of opinion that the appealed claims should also be allowed.
The decision of the Commissioner of Patents is reversed, and *521the clerk is directed to certify these proceedings as by law required. Reversed.
Mr. Chief Justice Covington, of the Supreme Court of the District of Columbia, sat with the Court in the hearing and determination of this appeal in the place of Mr. Chief Justice So EPARI).