PITTSBURGH REDL'CTION CO.
COWLES ELECTRIC S. & A. CO.
PITTSBURGH RIJDUCTIOX CO. v. COWLl<JS ELEOTRIC SMELTING & AI,UMINU)1 CO.
(Oircuit Oourt, N. D. Ohio, E. D. January 20, 1893.) No. 4,869.
PATENTS FOR INVENTIONS-A1I1'ICIPATION-·ALUMINUM BY ELECTROLYSIS.
Letters patent No. 400,7GG, gl'llnted April 2, 188!l, to Charles M. Hall, for an improved process of reducing aluminum by electrolysis, which process consists in dissolving alumina in a fused bath of the fluOlides of aluminum and of some metal more electro-positive than aluminum, and then passing an electric current through the fused mass, wherdly the aluminum of the alumina is precipitated at the cathode and its oxygen liberated at the anode; the bath meanwhile being unaffected aB to its chemical composition. One De Ville, in a work on aluminum, published in 1859, described a process of coating copper with aluminum, in ,vhich the bath is the double chloride of aluminum and sodium, the cathode a bar of copper, and the anode a bar of aluminum. 'When the current is passed through the bath the chloride of aluminum is decomposed, the aluminum is deposited on the copper, and the chlorine gas, freed at the anode, attl1cks the bar of aluminnm, and forms the chloride again, thus keeping the bath constant. Held, this ,vas clearly no anticipation of Hall's patent. De Ville described a modification of this procE'ss, in which the bath is cryolite,-a double fluoride of aluminum and sodium,-and the anode a compact mixture of carbon and alumina, which, upon the passage of the current, gives the following reaction: The fluoride of aluminum is decomposed, its aluminum precipitated at the cathode and the fluorine at the luwde, where it combines with the aluminum of the alumina, to form again the fluoride, and sets free its oxygen, whieh combinE'S with the carbon to form carbonic oxide. Held, that this is not an anticipation of the Hall patent, inasmuch as the electrolyte is not dissolved alumina, as in tho patent, but is the fluoride of aluminum,-one component of the bath itself; and the bath does not remain constant, but requires continuous renewal by the electro-chemical solution of the alumina of the anode.
Even though the alumina from the anode in the De Ville process waEl dissolved in the bath and electrolyzed, he made no note of the fact, and it must be deemed an accident, which he failed to observe, and therefore it would not constitute any anticipation of the patented process. In order to show that the Hall process was identical with that of De Ville, the theory WaB advanced that in the former the electrolyte is not the dissolved alumina, but the fluoride of aluminum of the bath; and that, when this fluoride is decomposed, the fluorine attacks the dissolved alumina, drives off the oxygen to the anode, and unites with the aluminum remaining, thus restoring the bath. Held that, even if this were true, the Hall process would still be patentable for the regeneI'lltion of the bath accomplished by it is complete, and free from the escape of the corrosive fluorine gas, which renders the De Ville process a failure for commercial purposes. This theory of the reactions in the Hall process is, however, shown to to be invalid by the facts that the alumina dissolves without any evidencH of chemical ;LCtion; that the action of the current gives no evidence or other products of decomposition than aluminum and oxygen; and that, as scon as the alumina is eXhausted. th,) resistance to the current is doubl\ld, indicating that the electL'olytehas been changed; and, mo:reover, the theory contains a in aB8uming, on the hand, tha.t the dissolved alumina will be decomposed by the fluoride of aluminum, and,
on the other, that the alumina is a more stable compound when electrolysis ensues so that the fluoride becomes the electrolyte.
SAME-"OXYFLUORIDE OF Ar,uMINuM."
The theory that when the alumina is dissolved in the bath in Hall's process there is found "an oxyfluoride of aluminum," which becomes thE; electrolyte, cannot avail to affect the validity of the patent, for it does not appear that any chemist has ever isolated any such compound, or known tltat it exists.
Hall's claim to be the discoverer Of the fact that cryolite will freely dissolve alumina to the extent of 10 to 25 per cent. of its own weight is not prejudiced by the fact that it had been used to wash off the film of alumina adhering to the globules of aluminum produced by De Ville's chemical process, for it appears that it was so used only as a substitut<l for fluoride of sodium or fluoride of calcium, either of wWch "'.ill dissolve no more than 1 per cent. of its own weight of alumina. Knowledge of this solubility of alumina in cryolite is not shown by the fact that in several English patents issued for the De Ville electrolytic process the anode of carbon and alumina is described as "soluble," for the anode of pure aluminum is likewise called "soluble," and the term is indicative only of the action of the fluorine gas in attacking the aluminum of the anode and forming the fIuQl'ide.
A French patent was granted to one Fuerst August 8, 1884, for an electrolytic process of producing aluminum from alkaline alunlinates in solution or fusion, alumina being added to l;egenerate the bath. 'I.'he process, as described by him, was admitted to be inoperative; but he mentioned as one of the "indifferent or auxiliary bodies" that might be present in Ws hypothetical electrolyte, hJ'drofluoric acid; and it was shown by experiment that, if there be added to" ;liuminate of soda eight times its weight of hydrofluoric acid, there would result a double' fluoride of aluminum and sodium, wWch, upon the addition of alunlina, and the passage of the current, would give the Hall process. exactly. Held, that this experiment cannot avail to show an anticipation by Fuerst, for Ws mention of hydrofluoric acid as an "indifferent or auxiliary body" will not cover its use in excess, as herein; and, moreover, the experiment violates his express injunction that these foreign bodies, whatever they may be, shall not produce decomposition of the Illuminates employed. The means described in Hall's patent for effecting the process covered by it included the fusion of the bath by external heat before the current was passed through it to decompose the. alumina, and a plant was constructed and successfully operated upon this method. It was subsequently discovered that the resistance oftbe components of the bath to a current sufficiently strong to accomplish electrolysis produced heat enough to maintain the fusion without the aid of external heat, a possibility suggested by Hall in his first specifications. Hela that, even though the use of internal heat as a means of fusing the bath and carrying out the process might be such an improvement on the use of external heat as to render business compeTition between the two methods impossible, nevertheless the process was the same, and, as the method with external heat did accomplish a useful result, Hall, as the patentee, was entitled to the exclusive right of his process, whatever were the subsequent improvements on his method or· apparatus for 'carrying it out.
SAME-PROCESS-IMPROVEMENTS IN METHOD.
Hall used a carb'o1i anode in his experiments before' applying for a patent,. but in his application he stilted that there were certain disadvantages incident to its use, and it 'wasnot embodied in amended claims· until· more than two years thereafter, 'when it had been included in the claims of a pending application for a patent for the same process, ·which'was refusedupou an interference with Hall's patent. Hela; that
SAME-:ELEMENT OF CLAIM-ABA:NDO:NMENT.
PITTSBTJRGH REDUCTION CO. tI. COWLES ELECTRIO S. " A. CO.
this did not amount to an a.bandonment to the anode. '
ot the carbon
The Hall claimed a bath "composed ot the ftuorides ot aluminum and a metal mO,re electro-positive than aluminum." In his specification he described a bath composed of fluorides ot aluminum and sodium, "these salts being preferably mingled together in the proportions of 84 palts of sodium fluoride and 169 parts of aluminum fluoride. A convenient method of forming the bath consists in adding to the mineral cryolite 338-421 of its weight of aluminum fluoride to secure in the bath the proller relative proportions of the fluorides. Such proportions may be vaIied within certain limits without materially affecting the operation or function of the bath, as, in fact, any proportions which may befound suitable may be employed." Held, that this could not be construed as a disclaimer of the use of cryolite alone (which is a double fluoride ot aluminum and sodium) for the bath, and that the patent covel'S every double fluoride of aluminum and sodium which can be made to produce aluminum when used as a bath in the Hall process.
The facts that Hallin his speclflcations describes an apparatus for the bath by external heat, and that the claim speaks of dissolving alumina in the fused buth, "und then pussing an electric current," do not limit him to the use of external heat as against the heat developed by the current itself, for the claims contain nothing as to the production of the heat, and the patent states that the apparatus described therein forms no part of the invention. Following Tilghman v. Proctor, 102 U. S. 707. The claim in the Hall patent of a "carbonaceous anode" covers both anodes made partly of carbon and those composed wholiy ot that substance.
SAME-CONSTRUCTION OF CLAIM.
In Equity. Bill to restrain infringement of patent. Decree for complainant. George H. Christy and W. Bakewell & Sons, for complainant. Henry S. Sherman, Leggett & Leggett, and Frederick S. Betti, tor defendant. Before TAFT, Circuit Judge, and RICKS, District Judge. TAFT, Circuit Judge. This is a suit in equity by the Pittsburgh Reduction Company against the Cowles Electric Smelting & Aluminum Company, to restrain the infringement of a patent process for reducing aluminum by electrolysis, (letters patent No. 400,766,) owned by the complainant under an assignment from the original patentee, Charles M. Hall. The patent was applied for July 9, 1886, and was granted April 2, 1889. The defenses to the suit are: First, that the patent is invalid for want of novelty; and, second, that the defendant does not infringe. Electrolysis is a process for separating a chemical compound into itllelements by passing through it an electric current. The current is effective for this purpose only when the compound is reduced to a liquid state. either by ,solution or fusion. The compound which is decomposed by the current is called the "electrolyte." Aluminum is a metal which was first isolated by Wohler in 1827. There is great difficulty in obtaining the pure metal from its compounds because of the tenacity with which it unites with other