TAFT, Circuit Judge
(after stating tbe facts). We have in this case to deal with the use of the electric current to perform two functions in metallurgical operations. Whenever a current of sufficient quantity and intensity is passed through a chemical com-, pound in a fluid condition, it will cause a chemical disruption, and one of the elements will go to the anode, or the place at which the current enters the fluid mass, and the other will go to the cathode, or place where the current leaves it. This chemical dissolution by the current is called “electrolysis.” If the compound to be treated is metallic, the metal element will gather at the cathode, while the other will go to the anode. If the other element is a gas, as it is when the ores are oxides, the oxygen or other gas will bubble out of the bath at the anode. The effort that the electric current has to make in order to pass through any body or matter produces heat. The greater the resistance, or, what is the same thing, the lower [367]*367the conductivity of a material, the more heat will be generated by forcing a current through it. Heat can thus be produced of great intensity. The highest heat known is that caused by the electric arc, where the current forces its way through The air and completes the circuit. The usual way of reducing metals from their ores has been to fuse the ores by the heat of combustion in the presence of what is called a reagent. The reagent is a substance with a stronger chemical affinity for the noniuetallic element of the ore when the ore is melted than the metal sought. The result of the melting and reaction is that the metal is left pure. Whenever the ore is an oxide, carbon will serve as a reagent, because the affinity of carbon for oxygen Is very strong. Carbon is a conductor of electricity in which there is sufficient resistance to the passage of the current to generate a very great heat. The Cowles brothers conceived the idea of a furnace for reducing ores by the use of electricity in which granulated ore should be mixed with granulated carbon, so that the carbon should form a continuous conductor from anode to cathode. The passage of the current would generate heat in every particle of carbon throughout the furnace, and would soon fuse the ore, when the carbon, acting as a reagent, would take the oxygen from the fused compound, and leave the ore pure. Whether electrolysis necessarily took place in the furnace I shall discuss later.
Bradley’s process of 1883 was a fusion of the ore, unmixed with carbon by the electric arc, an electrolysis of the fused ore, and a maintenance of the fusion from the heat generated by the passage of the current and the electrolytic action. There was no reagent in the Bradley process. The only agent of dissolution, except the fusion, was the current. - In 1885, the Cowles brothers were convinced that they had made a great discovery, — one which would revolutionize the art of winning the rarer metals, like aluminium, from their usually refractory ores. As they were forming their company, they learned that some one else had made a similar discovery. They wished to buy peace, as their counsel says, and so they proposed to buy from Bradley and Crocker the invention which threatened to destroy the value of their own, and, to make themselves perfectly secure, they secured the assignment of all other inventions or discoveries of the assignors which would tend to interfere with the monopoly they hoped to enjoy from their own. They were seeking insurance from invasion hv the assignors, and so the assignment was made to cover patents, applications, and discoveries which never were, and which the assignors, of course, knew bad no existence. Bradley and Crocker were willing to make the language thus broad, because, as it could convey nothing, it did them no injury. The intention of the Cowles brothers was not: only to secure the application which bad interfered, but also to have a most sweeping guaranty from Bradley and Crocker that they had no other discovery which would interfere with the Cowles discoveries. This is the only explanation possible of the assignment of European patents and applications, and of the reference to inventions, applications, and patents all in the plural, in addition to [368]*368the ■ application specifically assigned. It is not claimed that Bradley and Crocker represented that they had other inventions and discoveries which would satisfy the words of the assignment. It is manifest that the general and indefinite language was used only to secure the Cowles Company against possible and undisclosed inventions, and not for the purpose of including inventions known to both parties to be in existence. ' ‘
With the general purpose of the parties in the framing of the contract well understood, we come to the question whether they intended to include in the assignment Bradley’s electrolytic process of 1883. The evidence establishes beyond controversy that when the assignment was drawn and executed the Cowles brothers knew that Bradley had applied for a patent for a process of reducing metals by electrolysis in which the current also effected the necessary fusion. They knew this from the Bradley and Crocker application which they were buying, in which the Bradley process was not only described, but the patent office number was given. It was discussed by them. Had the Cowles Company then intended that it should pass by the assignment, it is not possible that it would not have been specifically mentioned therein. The Bradley and Crocker application was identified in the assignment by number and otherwise. Why not Bradley’s? On its face, the assignment purported to convey Bradley and Crocker’s applications, patents, and discoveries. This was the stronger reason, if an individual application of Bradley was to pass, to make the reference to it free from doubt. The Cowles Company was using general terms to describe patents'and applications in the assignment for fear that the assignors might have others undisclosed. But here was one brought to its attention while thg contract was being drafted. Surely the failure to mention it specifically is strong evidence that it did not intend or wish to acquire it. Otherwise, why did not the Cowles Company at once take steps to prosecute the application to a patent as it did in the case of the Bradley and Crocker application? For eight years it made no claim of title to the Bradley application. It is suggested that, at the time of the assignment, it stood rejected. But the Cowles Company did not know this, and, even if it had, rejections are not final in the patent office, as the many rejections of this very application abundantly show. It is fair also to infer that Bradley did not suppose he had included his application of 1883 in the assignment, because from 1885 until the issuance of the patent, in 1892, Bradley pressed for its allowance.
The circumstances present convincing evidence that neither of the parties -to the assignment thought that the Bradley application of 1883 was within its terms. But this conclusion does not dispose of the case. It was the purpose of the parties to this assignment that a certain class of discoveries, applications, and patents, if owned by the assignors, should pass to the assignee. The description of them ex industria was made general, so that it might include individuals of the class whose existence was not known. If, now, it appears that there was an application which must be included within the general description to effect the purpose of the [369]*369assignment, can the court exclude it from the operation of the gruñí:, because both parties at the time of the assignment knew of its existeuce, but were ignorant that it was within the description of the class to be conveyed? It does not seem so. The question of construction is, what did the assignors intend to convey? If a class, then all the individuals fairly within it must, be included in the assignment. The very object in a class description is to avoid the necessity of mentioning individuals, and to include individuals which might otherwise be omitted. It follows that the mistake of the parties in thinking that a certain individual is not of the class conveyed will not exclude it from the grant. But the fací: that both parties do not think the individual to be in the class described may be a pregnant circumstance to show in what sense the words describing' the class are used, if those words are capable of several meanings. This, then, brings us to the question whether the Bradley application of 1883 is fairly included within the words of the grant. The important words are:
“Any and all discoveries and inventions relating to electric smelting processes and furnaces, and all patents they have obtained therefor, and all applications now pending and caveats on file in the United States patent office relating to electric smelting processes and furnaces, which do or may interfere with any applications for patents made by Eugene and Alfred H. Gowles, of Cleveland, Ohio, now pending in the United States patent office.”
It is clear that Bradley’s application of 1883 was not included in the grant, unless it related to electric smelting processes and furnaces, i. e. unless the process described therein was an “electric smelting process,” as that term might reasonably have been understood by the parties when the assignment was executed. The meaning of terms often changes from time to time, and the words of a contract are to be construed as of the time when it was entered into. “Smelting ” by its derivation, is synonymous with “melting,” but in metallurgy and the commercial manufacture it has come to have a more contracted meaning. Thus Prof. Morton, the expert for the defendant, quotes, from a treatise on metallurgy by Frederick Over-man. this distinction between “melting” and “smelting”:
“When metallic ores are exposed to heat, and such reagents as develop the metal, we call it ‘smelting,’ in contradistinction from the mere application of heat, causing the ore to become fluid, which is called ‘melting'.’ ”
Prof. Morton, however, is of the opinion that “smelting” really means nothing more then “melting apart,” and that any process in which the melting apart or separation of a metal from its ore is effected by the use of electricity is correctly described as electric smelting, and therefore that the Bradley process was electric smelting.
Prof. Langley, the expert for the complainant, thus defines “smelt”:
“The word ‘smelt’ is customarily applied to that class of metallurgical operations in which a metal results, said meial being in a metallic condition, and obtained from an ore or mixture in which the metal originally existed in the form of a chemical conxponnd. In all instances the operation of smelting results in producing something different from the body operated upon, and This change is brought about by the action of heat and chemical force. Usually the chemical action involved is between carbon, on the one hand, and [370]*370the oxygen of the ore, on the other; as, for example, in the smelting of iron, the ore, which in this case is always an oxide of iron, is introduced into a furnace where it comes in contact with hot carbon, which removes the carbon chemically by combining with it and sotting the iron freo. ‘Smelting,’ then, may be said generally to indicate the melting of something by heat, accompanied by a chemical change induced by the substances present in contact with the ore. The two exceptions just alluded to in this definition are— First, the case of bismuth, in which the bismuth exists in a metallic condition; and, secondly, the Lake Superior ores of copper, where the copper also exists in a metallic condition. In both of these instances it is sufficient merely to raise these ores to a temperature sufficient to melt the contained metal, and chemical action is not, therefore, necessarily present, but, even in those cases, chemical action is resorted to practically to render the earthy materials of the ore fusible, and thus render the separation of the metal more perfect. The substance added to bring about a chemical change in the earthy matters of the ore are called ‘fluxes,’ and they generally consist of limestone or of limestone and clay, so that, in the practical sense of the word, one may say the term ‘smelting’ always involves melting by heat and the concomitant presence of a chemical change.”
On cross-examination, Prof. Morton was asked this question:
“Can you refer me to any instance of the use of the word ‘smelt’ or ‘smelting’ to signify the decomposition of a compound by the action of the electric, current by any writer of recognized accuracy or authority? Ans. Not without the addition of the word ‘electric.’ As far as I am aware, the use of this compound word was first introduced into literature by the Messrs. Cowles in connection with their process, in which they described the operation which took place as electric smelting.”
The first application of the Cowles brothers was filed December 24, 1884, and the patent was issued in June, 1885. This described the process, and was termed the “Process of Smelting Ore by the Current.” On February 24, 1885, their second application was made for the apparatus by which this process might be successfully and commercially carried on. This was termed “An Electric bmelting Furnace.” The most general claim describing the process in the first patent was as follows:
“The method of smelting or reducing ores or metalliferous compounds herein described, which consists in subjecting the ore in the presence of a reducing agent to the action of heat generated by passing an electric current through a body of broken or pulverized resistance material that forms a continuous part of the electric circuit, the ore being in contact with‘the broken or pulverized resistance material, whereby the ore is reduced by the combined action of the reducing agent and of the heat generated solely by the resistance of the broken or pulverized body through its mass.”
It seems clear to me that the reason why the Cowles brothers called this an “electric smelting process” was because its main feature was like that of any smelting process as ordinarily understood, namely, the use of high heat and a chemical reducing agent, and because the heat was produced by electricity. The use of the carbon to attract the oxygen of the fused ore by chemical affinity most naturally suggested the smelting of iron and other metals by the same reagent. Before .that time ores had been fused, and then subjected to electrolysis. If “smelting” meant only “melting apart,” then this was smelting by means of electricity, but it was never so called. Even the Siemens arc furnace of 1877 was not described as an electric smelting furnace. It remained for the Cowles brothers to invent [371]*371tbe term to distinguish their discovery, and we may gain some idea of the sense in which they used it at the time of the assignment by reference to their idea of what their discovery was. Its important and main features, in their judgment, were the intense heat of the current made available by distributed carbon and the chemical reaction caused by the same agent. The many articles written by the Cowles brothers, and by disinterested scientists, together with the evidence of Alfred Cowles in an interference proceeding between the Cowles application and that of one Faure, are all quite convincing that, in 1885, they thought that, though electrolysis might play some part in (he process, the main success of it was due to the smelting effect of the high heat, and the chemical reaction between the carbon and the noninetallic element of the ores, and that a process which was purely and solely electrolytic was not embraced within the meaning of the term “electric smelting process” as they used it. This conclusion is still further borne out by the circumstance, already commented on, that though the parties to the contract of 1885 had before them and under discussion this very Bradley process, so described as to bring it clearly within the definition of “electric smelting” now contended for by the defendant and given by its witnesses, yet no specific words were used in (he contract either to include the process in, or exclude it from, the operation of the assignment as would have been most natural, had the process been an electric smelting process, as it was then understood by the parties. There can be no doubt either of the distinction which the assignors in the assignment made between such a smelting process and one of electrolysis, for in the very application which the Cowles Company bought by this assignment of May 8, 1885, Bradley and Crocker distinguished the Bradley process of 1883 from the equivalent of the Cowles process, as follows:
“Tlie present invention (i. e. tlieir cartoon smelting process) resembles the above (i. e. the Bradley process of 1883) to a certain extent; tout in the present invention the electric current which we employ performs no electrolytic action, the reaction which takes place toeing purely chemical, and the function of the current toeing solely to develop the heat which Is a necessary condition of the reaction. For this reason our invention does not require the use of a continuous current of electricity. An alternating current may toe employed if desired, which is an advantage, since large alternating current, dynamos may toe constructed more cheaply than the continuous current machines, and it is also less trouble and expense to return them.”
The Cowles Company took this application, and pressed it lo a patent, which was issued to it as assignees, and, though the claim for the fundamental process was waived, that for an improvement thereon was retained, and the foregoing explicit declaration of a radical distinction between the carbon electric smelting process and the Bradley electrolytic process still appeal's in the specifications of the patent, and is, in effect, a formal admission by the Cowles Company, without which it may he presumed the patent would not have issued to it. From the whole record, I feel sure that the parties to-the assignment of 1885 did not use the term “electric smelting processes” in the wide sense claimed on defendant's behalf, and that, in their minds, processes solely electrolytic were not embraced within [372]*372it. Therefore the Bradley process of 1888 was not conveyed to the Cowles Company by the assignment, and it never acquired title.
But suppose that I am wrong in thus limiting the meaning of the words “electric smelting process,” and that even in 1885 it did include any process in which by the use of the current ores were melted and separated, even if there was no chemical reaction at all. The discoveries, patents, applications, and caveats relating to electric smelting processes and furnaces assigned by Bradley and Crocker are only those “which do or may interfere with” the Cowles patents. It has been pressed upon the court that these words modify only the phrase immediately preceding, namely, “caveats on file,” etc., and do not qualify the terms “discoveries,” “patents,” and “applications.” This is much too narrow a construction. The Cowles Company was buying peace, and the clause in question was expressive of the intention which pervaded the entire document, and should be given its effect in construing every sentence and clause in it. We have found that neither of the parties thought that the Bradley process of 1888 was included in the assignment. We are now considering the question whether the general language of the assignment describing a class carried the process in spite of this common view of the parties. Certainly the court will lean to the construction of the general language used which may be reconciled with the common thought of the parties as to the particular process, and if, therefore, as I shall attempt to show, the construction, by which the discoveries, patents, and applications assigned are limited to those which did or might interfere with the Cowles patents, excludes from the grant the Bradley process of 1883, then it is the court’s duty to place that construction upon the assignment. Moreover, the reference of the clause, “which do or may interfere,” to all preceding subjects of the assignment, is a reasonable and grammatical interpretation of the language, for the relative pronoun “which” often has more than one antecedent, and there would seem to be no reason for thus limiting the caveats assigned without also limiting the more important words, “discoveries, patents, and applications.” The words, “do or may interfere,” are plainly to be construed with reference to the atmosphere in which the parties then were. They were in the atmosphere of the patent office. They were considering the question of applications, caveats, and patents, — all technical terms to describe different steps in the securing of a monopoly by government grant. The word “interfere” has a technical meaning in that connection. It is used in the statutes of the United States. Strictly speaking, an interference is declared to exist by the patent office whenever it is decided by the properly constituted authority in that bureau that two pending applications, or that a patent and a pending application, in their claims or essence cover the same discovery or invention, so as to require an investigation into the question of the priority of invention between the two applications or the application aud the patent.
In the strictest technical sense, therefore, the fact that the Bradley application of 1883 was not declared to be an interference with [373]*373any of tlie Cowles patents, and that the Cowles patents were issued. and as issued were not modified or affected, by the Bradley application of 1888, would exclude the Bradley application from the effect of the assignment. But it may be conceded that this is too strict an interpretation, and does not square with what appears to have been the manifest intention of the Cowles Company in securing (his assignment. The interference referred to was either a declared interference in the patent office, or the total defeat or the narrowing of any of the otherwise valid claims of the Cowles patents, after issuance, in a court of competent jurisdiction, by the use of an application or invention of Bradley and Crocker or either of them. If, therefore, it appears that the otherwise valid claims of the Cowles patents are not nan-owed or defeated by the specifications of the Bradley patents which.are the subject of this litigation, then the Bradley patents did not pass by the assignment. The question is not to he determined by what the Cowles brothers may have claimed in any application, nor by what might have been claimed under their specifications and drawings, had Bradley never made his invention or application in 1883. It is whether the claims allowed to the Cowles brothers by the patent office are restricted or invalidated by the really new inventions of Bradley, as disclosed by his application of 1883.
If the patent office allowed Bradley any claims which the history of the art shows he should not have been allowed, then those claims can play no part in this discussion. If invalid, they are invalid because anticipated by some other patent, or by the discoveries in the prior art, and it certainly cannot be held that claims thus narrowed or defeated interfere, in the sense of the contract, with any of i lie otherwise valid claims of the Cowles patents. The questions remaining, therefore, for consideration, are: (1) What was the real invention of the Bradley patents? and (2) what are the valid claims of the Cowles patents, excluding consideration, of the Bradley patent? and (3) are they interfered with by Bradley’s discovery of 1883?
For eight years, from 1883 to 1891, the claims of the Bradley patent were rejected by the patent office, the examiners ruling that the use of a current of electricity to fuse a metallic compound, and to íuainfain Ihe fusion, and to electrolyze the fused, compound, was old in The art, because íáix- Humphrey Davy had reported, as a contribution to science, his use of the electric current first to fuse, and then to electrolyze, potash and soda, securing a deposit at the cathode of the metal potassium and the metal sodium, respectively. In the collected woiks of Sir Humphrey Davy, reported in 1840, occurs this statement:
“T tried several experiments on the electrization of potash rendered fluid by heat, with tlit» hopes of being able to collect the combustible matter, but without success; ¡md l only attained my object by employing electricity as the common agent for fusion and decomposition. Though potash, perfectly dried by ignition, is a nonconductor, yet it is rendered a conductor by a very slight addition of moisture, which does not perceptibly destroy its aggregation, and in this state it readily fuses and decomposes by strong electrical powers.”
[374]*374' Sir Humphrey Davy also tried the experiment with alumina or other refractory ores or oxides, and did not succeed in fusing them, because the current would not pass through them in their dry state. It was known that these ores, if fused, could be subjected to the electrolytic action of the current, but it seems never to have occurred to any one but Bradley how the current might be used to effect the fusion of the metal in its nonconducting state, as part of the electrolytic process. He secured it by putting the anode and cathode so close together that an electric arc was formed by the passage of the current through the air. This, as was well known, produced the highest possible heat, and quickly fused the ore between or near the anode and the cathode. The power of fused ore thus produced became at once a medium for the conduction of the current. Thereafter the resistance to the current in the fused ore caused heat, which could be easily increased to effect the progressive melting of the rest of the ore, by adding to the voltage or intensity of the current.
The history of the Bradley patent shows, as disclosed above, in the statement of facts, that Bradley attempted to secure the allowance by the patent office of one claim or more for the process of main-' taining fusion and electrolysis by the electric current simultaneously in the treatment of metallic compounds. But it will be observed that even on appeal, and by the decision of the board of review imthe patent office, his claims in this regard were very much narrowed. He was required by the board of appeal to make, as an essential part of the process described in his specifications and claims, the initial fusing of the metal as therein set forth, and, as the only initial fusing suggested was that described in the patent to be by the electric arc, it became an essential part of the process patented.
The acceptance by the patentee after he had made the claim for merely maintaining the fusion, and simultaneously electrolyzing the fused mass, and it had been rejected, estopped him from ever afterwards asserting monopoly to such a process, when the initial fusion described in his patent was not included in it, and showed with reasonable certainty that he was entitled to nothing more. Bradley’s discovery, therefore, was of a combination of steps, each one of which was old. The steps were, first, the initial fusion by the electric arc between the carbon anode and cathode. The electric arc was certainly old. Second, the maintenance of the fusion by the heat of resistance to the current in the fused ore, and the consequent progressive melting of the rest of the ore. This step was plainly shown by Sir Humphrey Davy. And, third, electrolysis by the current, which was equally well known. Whether Bradley is really entitled to the monopoly of this combination or not may be questioned when the validity of his process is directly in issue. Both parties to this cause, in contending for the possession of it, have a motive not to diminish its scope more than is absolutely necessary to the establishment of his or its title, but sufficient appears in the record to justify the limitation of it as above. The other patent of [375]*375Bradley’s involved bere is for the use of a pile of ore as a containing vessel for the bath to be electrolyzed, in accordance with the directions of the main patent. It does not seem to me, except as it involves the process described in the main patent, to have any bearing on the question of interference with the Cowles patents. Having thus considered the scope and extent of the Bradley process of 188:}, we come now to consider what is the real essence of the Cowles .patents. The gist of the Cowles invention is the use of granular carbon or other equivalent resistance material distributed through the mass of granulated ore to carry the current from one electrode to the oilier, and by its low conductivity or resistance to produce intense heat, not at a single point or in a, single line, but throughout the ore, and by the heat thus generated to fuse the ore, and to separate the metal element by the chemical action of the carbon upon the nonmetallic element of the ore, just as iron and oilier like ores are smelted in a furnace.
The claims of the first or main patent of the Cowles brothers re-lab', the first one to the fusion of the ore by the process described, the second to'.its smelting or reduction by the reagency of the same carbon used to generate the heat, and the third and fourth claims are but variations froiu the second. This Cowles patent wars not intended to disrupt, the metallic compounds by electrolysis. There is a suggestion in the patent that the current has a disrupting] or disintegrating effect of assistance in the reduction and distillation of zinc ores in accordance with the specifications of the patent, like the disrupting effect of the current in the solution. Whether this obscure statement is a blind intimation that electrolysis takes place or not is somewhat difficult to determine. But:, even if it is, certainly the main purpose of the Cowles brothers in their patent was to accomplish the induction of the ores therein mentioned by the chemical reaction of the carbon, and not by the electrolytical disrupting of the ore. It is confidently claimed, however, on behalf of the defendant,' and the claim is rested on elaborate expert evidence, that the main agent in reducing metals from their ores by the Cowles process is the electrolytic action of the current: after the ore is fused by the heating contact of the incandescent carbon distributed through its pulverized mass. In my opinion, it is immaterial whether this theory be true or not, for, even if electrolysis is necessarily present in the Cowles process as the main and leading agent for its successful carrying on, the claims of the Cowles patents are not at all affected by anything disclosed in the Bradley process of 1883, either in the specifications or in the claims allowed by the disparIment. The only valid claims of novelty in the Bradley process, as we have shown, are of a combination which must have, as part of it, the initial fusion of the dry ore by the electric arc. This was the difficulty which Kir .Humphrey Davy seems not to have been able to overcome in the process of electrolysis with internal heating, and this difficulty, if the Cowles process is an electrolytic process, was overcome in it, not by the use of the electric arc, hut by the establishment'of a continuous current through granulated carbon placed between the anode [376]*376and the cathode. In other words, the Bradley process and the Cow: les process, if they both involve electrolysis, and thus cover common ground, do not interfere with each other, because the common ground covered was well known in the history of the art, and was not subject to the monopoly of either.
But much has been said concerning the suggestion in one of the Cowles patents (the one to Alfred Cowles, No. 319,945) that in some cases pulverized ore might alone be used where it is a sufficient conductor of electricity without carbon. This is the only suggestion of the kind in all the five patents belonging to the Cowles Company. It is said that, in furnaces operated with the granulated ore alone without the carbon, we should necessarily have a reproduction of the Bradley process, and therefore that the Bradley process would interfere with the Alfred Cowles patent to that extent. The argument is untenable, first because the evidence shows that the suggestion of the Alfred Cowles patent is wholly impracticable. There is no ore disclosed in the record which in its dry state is a sufficient conductor to permit the passage of a current, and, unless the current can pass through the resistance material which is to generate the heat, the process must be a failure. Again, the suggestion of the patent w'as never embodied in any of the claims allowed. Therefore the Cowles Company, without regard to the Bradley process, would have no monopoly on it, and their patents could not be said to be interfered with in respect of the process which they did not own.
Finally, I do not think that it is by any means clear that electrolysis in the Cowles patents, as they are described in the specifications of the patents, plays any considerable part in the reduction of metals. In the first place, in one of the Cowles patents it is stated that there is no deposit of metal upon the carbon plate which makes the cathode. There has been no evidence introduced to show that this statement is a mistake. If there were any electrolysis between the electrodes, the metal must be deposited at the cathode. Prof. Morton, the chief expert for the defendants, on his examination in chief developed and illustrated a theory by which every two pieces of the granulated carbon lying next to each other in the fused ore constitute an electrolytic pair, and electrolysis goes on everywhere in the bath, wherever two such adjacent granules of carbon could be found. Out of the mouth of this same witness, by the cross-examination of counsel for the complainant, who proved himself both on examination and in the argument to be a learned expert himself, the elaborate and convincing theory developed by Prof. Morton was shown to have.but limited application to the Cowles furnaces. His statement in chief gave the impression that the melted ore would find its way and form a film between every two adjacent grains of carbon in the furnace, and that between each two grains thus separated by the film an electric cell would form, and electrolysis would go on; but when counsel for the complainant brought out from the witness the fact that the counter electro motive force needed in each electrolytic cell for the work of electrolysis would require to produce electrolysis in the number of cells which must thus occur in a [377]*377Cowles furnace of ordinary dimensions a voltage three or four times that actually used in the Cowles furnaces, he was obliged to admit that the number of cells in the furnace would be much less than that which his answers in chief would have led a nonexpert to suppose. When his attention was called to the statement in the Alfred Cowles patent that there -was no deposit on the cathode of metal, he immediately supposed an aggregation of carbon granules there, so closely united as to prevent the fused ore from finding its way to the cathode, departing therein from the principal hypothesis of his theory, as originally stated, that the fused ore would necessarily thread its way in between all the loose particles of carbon in the furnace. The effect of his answers on cross-examination was to weak-1 en much the probative force of Ms general statement that the chief agent in reducing metals under the Cowles patents was electrolysis. Prof. Morton did demonstrate that some electrolysis must go on in 1ho Cou lea‘furnace, and this, indeed, was not denied on behalf of the complainant. He demonstrated it by electrolyzing a solution of sulphate of copper with carbon, in which the result of electrolysis was seen in the particles of copper distributed all over the bottom of the glass disk in which the experiment was performed, and not confined ito the cathode. While these show that electrolysis must go dn to some extent in the Cowles furnaces, they do not show that the smelting effect of the high heat and the carbon reagent is not the important and principal means of reducing the metal in the Cowles process-.
In one of the papers published in connection with the Cowles process, a Mr. Darrow reports an experiment by the Cowles Company for the purpose of determining whether electrolysis played any considerable part in the Cowles furnaces. His experiment consisted in the oi>eration of the furnaces with a continuous current, and then with an alternating current. It was conceded, at that time, that electrolysis was impossible in an alternating current. Prof. Morton and others question this,' but there is no substantial evidence that the theory is unsound. Mr. liar-row’s announced result was that there was substantially no difference in the product of the Cowles furnace from an alternating current and from a continuous current. Prof. Morton, from the figures of Mr. Darrow, thinks that there is a wide difference demonstrated. If such a difference could be shown, it would go far to prove the claim now made on behalf of the Cowles Company that electrolysis played a great part in their furnaces, but no such experiment has been attempted since Darrow’s, or, if attempted, has not been shown in evidence. On the whole, from the entire record, including the evidence of Prof. Langley and Prof. Haynes, and of Prof. Morton on cross-examination, I conclude that there is electrolysis present as an incidental feature in the Cowles furnaces, but that the presence of carbon, instead of ’aiding the electrolysis, interferes with it, and that it is by no means an important feature in the reduction of metals under the Cowles patent.
Evidence appears in the record of the operation of the Cowles furnaces at Lockport, N. Y., and these are used to show that electrolysis [378]*378must go on. One of the chief evidences is said to be the bubbling of the gas at the anode. But on cross-examination of the witnesses it was developed that the operation of the furnaces was a departure from the Cowles method, in that the carbon was only about 10 per cent, of-the mixture, and would hardly form a continuous conductor; that the fusion was begun by the electric arc; and that in fact the process described in the Bradley patent was the one which was used.
For the reasons given I am satisfied that the Bradley patent was not intended to be conveyed by the assignment of May 8, 1885, and that it was not, in any view, included within the general terms of that assignment. The finding of the court will be that the valid title of United States patents Nos. 464,933 and 468,148, issued to Charles S. Bradley and mentioned in the bill, is now in the complainant by lawful assignment; that neither the defendant the Cowles Electric Smelting & Aluminum Company nor Alanson T. Osborn has any title to these patents; and that the assignment of them, executed by the Cowles Company to Osborn, and placed upon the record in the patent office, had no effect to carry title to them, and constitutes a cloud upon the title of the complainant. The decree of the court will be that the defendants shall cancel the record of the said assignment .by the Cowles Company to Osborn in the patent office, and that the defendants, and each of them, shall be perpetually enjoined from asserting any title or claim of title to the patents described in the bill. The cross-bill of the defendant the Cowles Company will be dismissed, and the costs of the cause taxed to it.