The Thomas A. Edison Papers Digital Edition

Transcription

[Translation follows] [Translation follows] [Translation follows] [Translation follows] [Translation follows] [Translation follows] [Translation follows] [Translation follows] Dr. Alfred Wohl, University Professor, Charlottenburg,
3rd. August 1901
OPINION
About the German Patent Applications of
Mr. Thomas Alva Edison
On a Cadmium-Nickel and Iron-Nickel Accumulator
Before going into detail discussion of the different points, the following general remarks are to be noted:
It is a principle of the German Patent Office that an idea of invention, which has been previously pronounced, cannot be generally placed under patent protection, even if the previously described execution as extremely incomplete. To a later applicant protection will only be granted on the special feature or characteristics by which the previously expressed idea has been made practically effective or has been improved upon Opposition against this established practice has very little chance of success, especially in the present case. 
If it was only a quotation, which on the strength of $2 is held up against the novelty, then perhaps the argument could be made, that the invention is not so described by the question “that the exploitation would appear possible by other experts.”
In the present case of the Junior Patent, we are dealing with a legally existing patent and this will exclude later application on the strength of $3; in this paragraph however there is no provision of what nature the description should be, but it is simply set forth that the later application-of course in its generality is excluded “if the invention represents  the subject of the previous applicant.” The argument of incomplete description could only be brought up if it was successful to have the patent declared void for want of applicability.
The profound criticism of the Junger Patent as well as of the older Dun Patent by Edison is well suited to make clear the progress made by this inventor setting forth the invention character of his improvement, but these deductions and for reasons above given, not suited in the present state of the case to justify these comprehensive claims (made by Edison)
In several points, this criticism is, from an impartial standpoint, not free from objection as so for instance, the argument against the Dun Patent that it contains a misunderstanding of quite some consequence. Dun has not said that the intermixed metal oxides, conveyors, bring the copper to a higher oxidation, but on the contrary, that the labile copper peroxide, as a conveyor, will enhance the oxidation, but on the contrary, that the lablle copper peroxide, as a conveyor, will enhance the oxidation of the other metals.
Furthermore it appears to the undersigned to be left uncontradicted by Mr. Edison’s arguments, that the formation of soluble copper salts is based on the higher oxidation of copper. This point will be elaborated upon furtheron.
1.	COPPER ELECTRODE
Mr. Edison has not given any explanation for the formation of soluble copper salts with the previously known copper  salts with the previously known copper electrodes, nor has he given any reason why this disadvantage disappears with his disposition. It is only contested that the formation of soluble copper salts are observed simultaneously. This reason however is not any proof. Although a theory of current diffusion on inhomogeneous electrodes as yet does not exist, it is without any doubt that the current density may be different at different points of an inhomogeneous electrode. In accordance with this the potential of oxidation may also be different at different points of an inhomogeneous electrode and therefore it appears well well possible that simultaneously copper oxide is formed at points where finely divided copper is deposited and hydrate oxide of copper is formed at places of dense or solid copper deposits. It being a fact that alkaline solutions are never free from carbonic acid and it is also a known fact that hydrate of copper oxide and carbonate are soluble with blue color in carbonic alkalies. The undersigned recognizes in this effect the explanation to Edison’s discovery, that the exclusion of soluble copper salts is conditioned on the complete homogeneity  of the copper electrode and he recommends this view to be made the base it should also be explained in the description. The patent 1 claim would be as follows:
1.	Pole electrode for accumulators of copper oxide obtained by electrolytical oxidation of an entirely homogeneous copper sponge, which will be free from grains and dense parts to such a degree that the current density will be the same at all parts and thereby local over oxidation and the formation of soluble copper oxide salts is avoided
Claim II appears admissible 
Claim III is indisputable as long as the Junger Patent  is legally existing
NICKEL-ELECTRODES.
Through the American Patent No. 345124, Nickel-electrodes have been made known which have been produced by forming Hydrate of Nickel-oxide with Graphite. In view of this the original application on Nickel-electrodes does not contain, according to my opinion, anything novel that would appear worthy of protection. Whether the immersion of the mass in line water is essential for the usefulness, cannot, be judged without special experiments; this proceeding is the only part that might be put under protection. Besides, practical protection seems to be secured in a sufficient sufficient measure by the following application on an improved nickel-electrode.
In this second application on a nickel electrode, three distance inventions are described and it appears necessary to bring about an expression from Mr. Edison, whether he considers it as practically necessary, to place each one under separate patent protection in this case three separate applications are required. Under separate protection may be placed:
1.	Nickel depolarization electrode, characterized by the employment of a non-colloidal hydrate of nickel oxide which is obtained by precipitation out of Nickel salt solutions by means of Magnesia or alcalic earths, which after filling into the carrying plates is formed by the electrical current.
2.	Nickel depolarization electrode, characterized by the employment of Hydro Nickel oxide obtained from a liquid state and put into a carrying plates for the purpose of preventing any swelling of the material during formation by the current.
This latter application would have to be substantiated by the following arguments:
Up to the present time the material used for nickel electrodes was nickel oxide obtained by heating or Hydrate of nickel protoxide which first had to be formed by the current into nickel hydroxide. During this process, in consequence of the absorption of oxide in a swelling of the material sets in, which interferes with the production of respectively with the durability of the electrodes. This disadvantage is avoided if the hydro-Nickelpertoxide is transformed before mixing it with a carrier, by chemical means into Hydro-Nickloxide(Hydrous N12 03). This is new and an essential progress, because the extent fine distribution so obtainable, will permit a complete utilization of the oxidizing capacity of the nickel.
The hydro nickel oxide mentioned in the American patent Mo. 345124 is likely to be N1 (OH)2 and is known the designations as to protoxide and oxide in this case are rather undecided. It is a confirmation of this assumption, that the common Hydroxide of the bivalent Nickel is meant furtheron it is mentioned, that the peroxidable substance absorbs oxygen.
In case this assumption, that the American Patent No. 345124 the common nickel proxide hydrate is meant, cannot be maintained, then claim 2 cannot be held and it would be advisable in this case to combine claims 1 and 2 as follows:
Nickel depolarization electrode, characterized by the employment of non colloidal nickel protoxide hydrate which is obtained by precipitation out of nickel salt solutions by means of magnesia or alkaline earths and which is oxidized into nickel oxide hydrate either before filling into the carrying plates or after filling the same into the carrying plates and then oxidized by the electric current.
3.	The employment of graphite in the form here described had best be made the subject of a separate application, which would embrace its use for the nickel electrode as well as for others. As to the patent offices objection against the novelty of this measure I would recommend the construction of the claim as follows:
On electrodes, the active mass of which is produced by mixing metals, metal oxides or metal oxihydrates with graphite or other conducting and non-deteriorating material, the employment of coarse grained graphite, etc. the grain of which is preserved during mixing, combined with the employment of screen plates on the carrying plates for securing the mass, the screenholes being smaller than the grains of the graphite
III. IRON ELECTRODES
The claims 3 and 4 of the original applications are completely excluded by patent No. 107727. Claim 3 appears admissible bas far as the literature has been discussed to this point, but it must by all means form the subject of a separate application.
In this application the advantages of the combination Iron Nickel would have to be put forward as set forth by Mr. Edison Perhaps it would be advisable to restrict the original application to this point (claims 5 and 6) and to make the iron electrode the subject of a new application; the further improvement of the iron electrode could then be entered as a supplementary (Zuscatz) application, branched off from the main application.
The application on the iron electrode would have to be based on the following grounds, provided that the American Patents do not interfere.
For the production of iron electrodes only iron oxide combinations have been employed until now. If they are produced as described in patent No. 1077277 by gentle heating, then the resulting mass so obtained can be formed by the electric current only incompletely and with much difficulty. In case the highly voluminous iron hydroxide combinations obtained by wet process are used, then the space of the carrying plate cannot be completely utilized. If, finally the iron hydroxide combinations are dried beforehand, they will to a great extent become ineffective. Subject of the present application is the employment of iron combinations of the class of iron protoxides as active mass, which is to be brought to the carrying plate. The difficulty that iron combinations of the protoxide class, easily oxidize in the air, may easily be avoided, for instance by bringing in from iron sulphite and this be transformed into the hydroxide combination, etc.
Claim 1. Negative pole electrode of iron, characterized by the employment of iron combinations of the protoxide class which are brought into carrying the plates and formed by the current.
Claim 2. On negative pole electrodes as described in claim 1, the employment of iron sulphite which through alternating oxidation and reduction through the electric current is desulfurized.
The new supplementary application on would receive the following claim: On a pole electrode as covered by the main patent, the employment of iron monoxide or mixture consisting predominatingly of iron monoxide, which is made air proof cooling it in a stream of Hydrogen.
In conclusion I would like to make the following remarks in reference to the relations of the Edison applications the Jungner Patent.  
The Jungner Patent refers only to such metal oxides that are not constant in alkali solutions, and which by giving off water are spontaneously turned into oxide. This occurs generally only with the sub oxides, as for instance with silver oxide, copper protoxide, etc. In the contrary iron hydroxide, nickel hydroxide and cadmium hydroxide remain constant in alkaline solutions and therefore there exists no dependency of any kind to the Jungner Patent neither to the iron nickel nor to the cadmium-copper electrode.
Signed
A.	Wohl
P.S. In a letter received from Professor Wohl of Aug. 5th, he leaves it to our option to amend his formation of the iron monoxide electrode, page 7 on his report, as follows:
“On a pole electrode as protected by the main patent the employment of air resisting iron monoxide or of mixture essentially of air resisting iron monoxide.”