Ladoff v. Dempster

36 App. D.C. 520, 1911 U.S. App. LEXIS 5606
CourtCourt of Appeals for the D.C. Circuit
DecidedMarch 6, 1911
DocketNos. 656, 657, 658, and 659
StatusPublished
Cited by1 cases

This text of 36 App. D.C. 520 (Ladoff v. Dempster) is published on Counsel Stack Legal Research, covering Court of Appeals for the D.C. Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Ladoff v. Dempster, 36 App. D.C. 520, 1911 U.S. App. LEXIS 5606 (D.C. Cir. 1911).

Opinion

Mr. Chief Justice Shepard

delivered the opinion of the Court:

The foregoing appeals are embraced in one record and were heard together, for, while there were three separate interfei’ences, numbered in the Patent Office, 26,482, 26,483, and 26,485, respectively, one subject-matter is involved.

The counts of the several issues read as follows:

No. 26,482.
“1. An arc light electrode composed principally of titanium oxide mixed with a metallic material.
[522]*522“2. A homogeneous electrode for arc lighting consisting of titanium oxide intimately mixed and conglomerated with a metal having greater conductivity than said oxide.
“3. A homegeneous electrode for arc lighting consisting of titanium oxide intimately mixed and conglomerated with iron.
“4. An arc light pencil comprising titanium oxide intimately mixed and conglomerated with metal having greater conductivity than said oxide, substantially as and for the purpose described.
“5. An arc light pencil comprising titanium oxide intimately mixed and conglomerated with iron, substantially as and for the purposes described.
“6. An arc light electrode essentially metallic in composition containing titanium oxide.
“7. An arc light electrode composed principally of titanium oxide homogeneously conglomerated with a metallic substance having greater conductivity than said oxide.”
No. 26,483.
“1. An arc light electrode essentially metallic in composition, containing metallic iron and a titanium compound.
“2. An arc light electrode composed largely of a metallic conducting substance conglomerated with a titanium compound.
“3. An are light electrode essentially metallic in composition, and containing a titanium compound.”
No. 26,485.
“An essentially metallic arc light electrode comprising ferric and titanic materials.”

In each interference the application of Ladoff, filed June 3 8, 1904, is a division of his original application filed December 2d, 1903.

In interference No. 26,482, the application of Dempster was filed December 10th, 1903; in the other two, on March 26th, 1903.

The Examiner of Interferences awarded priority to Dempster on every count of each issue. On appeal to the Examiners-[523]*523in-Ohief, he was affirmed as to each count, save 2 and 3 of No. 26,482, which were awarded to Ladoff. The Commissioner affirmed their decision. Each party has appealed from so much of the decision as is against him.

The arc light electrode in controversy was discovered and developed in the laboratory of the General Electric Company at Schenectady, New York. That company is the assignee of Dempster, while the invention of Ladoff is claimed by the Adams- Bagnall Company of Cleveland, Ohio, an exclusive licensee. The litigation has been conducted by said corporations. Prior to this invention carbon electrodes were in common use. These were, at first, burned in the open air, but free access of oxygen made them burn rapidly. Later, globes were used, which protected them to a considerable extent from the oxygen of the air, which increased their life, but caused a decrease in candle power. Later still, the flaming carbon Wiis introduced through the addition of certain compounds, the volitization of which produced a colored light of high candle power. This necessitated burning in the open air and shortened the life of the electrodes. Some time in 1901, Charles P. Steinmetz, a distinguished chemist connected with the General Electric Company in an advisory capacity, originated the idea of using magnetite as a substance for electrodes, to overcome the disadvantages of those made of carbon. Practically incombustible, it would have a longer life, and at the same time would give a brilliant white light, attributed to the spectrum of iron. It seems also that Steinmetz had the idea of using titanium in some of its many forms or compounds with the magnetite. The General Electric Company maintained a large and well-equipped laboratory for the purpose of research and the development of all ideas looking to improvements in the electrical art. This laboratory was under the direction of Professor Whitney, who had a corps of assistants. All of these were under contracts with the company to assign their inventions to it. Dempster, a chemist, was one of these assistants. Ladoff, also a chemist, was employed at laborer’s wages. He was not employed in research work. [524]*524So far as we can judge from the record, he was a more accomplished chemist than Dempster. Sometime in 1902, Demp-' ster was assigned to work in developing the Steinmetz magnetite electrode. He kept a notebook in which he entered brief statements of his experiments, and from time to time also made written reports to the head of the department. November 4, 1902, he reported an experiment with a composition consisting of 80 per cent magnetite, 18 per cent red oxide of iron, and 2 per cent potassium titanate, or hydrafe of potassium. This combination is the basis of Dempster’s application made March 26, 1903. The iron tube or shell for electrodes was then well known in the art. Into this he proposed to force a core composed of the mixture above' described, the materials being powdered and moistened sufficiently to become plastic and moldable. After molding, the-pencils, so called, were baked for about twenty-four hours in air gradually brought to a temperature of 200° C., which dried them. They were then packed in crucibles surrounded with granular material, such as magnesium oxide, flint, or red oxide of iron. The crucibles were placed in a muffle furnace gradually brought to a temperature of 1,200° C., which was maintained for an hour. As described in the applications “The effect of this last heating is to convert the red oxide of iron, which is unstable at the temperature employed, into the magnetic oxide of iron, the excess of oxygen being, freed and driven off. The packing which surrounds the electrodes in this heating action prevents any other reducing action than that named from taking place.” The potassium titanate or hydrate is described as having the effect to reduce the fusing and vaporizing points, thereby increasing the material which is vaporized upon the passage of a given current. The iron tube has one end treated to riiake it conductive, a simple method of which consists in fusing it over in the electric arc. It is also stated that if the muffle furnace in which the electrodes are treated be raised somewhat over 1,200° C., the granular material of the pencils will flow together sufficiently to make the pencils comparatively good conductors of electricity, in [525]*525which case they may be used without the incasing iron tube. The difficulty in this last operation, as suggested, is that without great care the electrodes will be blistered by the heat and their shape distorted. The earlier claims of this application call for a poorly conducting filling forced into a shell; a mixture of magnetic oxide of iron and a smaller proportion of red oxide of iron, moistened and molded; the same mixture with a suitable blending material; the addition of potassium titanate to iron and oxygen chemically combined.

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Bluebook (online)
36 App. D.C. 520, 1911 U.S. App. LEXIS 5606, Counsel Stack Legal Research, https://law.counselstack.com/opinion/ladoff-v-dempster-cadc-1911.