[D0104AAP], Letter from Thomas Alva Edison to Germany. Patent Office, October 12th, 1901


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[D0104AAP], Letter from Thomas Alva Edison to Germany. Patent Office, October 12th, 1901




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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University


Berlin Oct 12 1907
E 7423 IV 21st
To the Vainerliche Patentant
In the several Edison Cases concerning accumulation we have asked for an appointment for a verbal conference with the examiner in order to facilitate the discussion we herewith give a short review of the state of affairs or viewed by us, and if the suggestions for application, which will be made at the conference.
The original Copper-Cadmium Application E 7276 has been limited to a positive pole electrode of a Copper-oxygen compound which later is obtained by electrolytical oxidation of a perfectly homogenous mass of finely divided copper. The application thus limited was handed in our Sept 27 1907.
The divisional application E 7426 has been limited to a cadmium-electrode, the finely divided cadmium of which is in a filamentary store and to a process for the preparation of this filamentary ed. The limited applications were filed on Sept 27.
For the eventual filing of a second divisional application of the appl E7266 with unchangeable electrolyte, we apply for an extension, as the opinion of the undersigned representative does not coincide with that of Mr. Edison, and as conference upon that subject is being continued after the arrival in Berlin of one of Mr. Edison's assistants.
The original Nickel-Cobalt-Iron-application shall be limited to the combination Nickel-Iron. In order to substantiate the patentability of the combination, we refer to our papers filed on May 27th 1907. In addition hereto we remark that the combination Ni-Fe in the first practical accumulator while the combinations suggested by Junger himself are perfectly inoperative.
From the application E7423 we have already separated the application E 7666. Besides this application we shall branch off a further divisional application, which has as subject the iron electrode. We consider as patentable feature against the iron electrodes referred to by Mr. Patent office, that there is used as active [illegible], to be formed by current a ferrous compound or iron compound still lower in oxygen, alone or in mixture with more or less inert materials. Such electrodes are very much more active than electrodes containing compounds richer in oxygen, which have so far been known. This is explained by the fact, that iron compounds richer in oxygen are difficult to reduce in presence of alkali hydrates.
The above mentioned application E 7666 now existing, shall be limited to a positive pole electrode consisting of Ni-oxygen compound to be used in accumulator having as electrolyte solution of alkali hydrate in water, whereby the Nickel oxygen compounds are enclosed under pressure in containers with perforated inert walls. In order to substantiate the patentability of this combination we refer to our criticism of the Sum and Nicholowstoy patents. The Am Pat. 345724 lately referred to as interfering, does not interfere as in this case the nickel-oxygen electrodes work differently on reason of the admixture of sulphate, which is decomposed by the current Thus the only conditions which Nickel-oxygen electrodes may be successfully used have not till now been known is explained by the fact, that all known literature on that subject is based on purely theoretical considerations. A claim therefore appears justified on the method by which the employment of electrodes of nickel oxygen compounds can produce practical oxygen compounds can produce practical results.
In order to restrict the application E 7666 to one subject, we shall make subject to a separate application the admixture of [illegible] graphite to the electrode [illegible]. The patentability of this mode of employment as against the admixture of [illegible] graphite ([illegible] reduce in size, ordinarily crush) is demonstrated by the following.
When a cube of graphite is split up unto 10 leases it offers a surface 10 times larger then the original without increasing the [illegible] of the graphite.
Consequently the employment of graphite in a [illegible] state offers considerable advantage to the use of graphite as powder or in lumps, which justifies the granting of a patent. The application of 7652 or a modified iron electrode shall be maintained and considered as a supplement to the application which will be branched off from appl. 7666 on an Iron-electrode in which the masses, that is to be found by current contains ferrous or lower iron compounds.
Finally we shall limit the appl. E7653 so as to treat only the special way of mixing the active [illegible] with the graphite and the maintenance of a fixed relation between the size of the graphite flakes and of the opening of the container enclosing the electrode [illegible]. It is assumed that by such limitation this application can be maintained as a supplement to the one; generally claiming the admixture of [illegible] graphite to elec. mass. Regarding appl E7654 we remark that in no one of the literature references brought up, contains with elastic walls have been mentioned. By this elasticity the essential new effect is obtained: to secure a continuous perfect contact swell on the absorption of oxygen in the electrolyte, the indispensable condition for a successful working of the accumulator.
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