Court Opinion

ID: 8804425
Source: CourtListenerOpinion
Date Created: 2022-11-26 14:43:13.97387+00
Date Added: 2024-06-11T17:04:02.195002
License: Public Domain

WOOLLEY, Circuit Judge.
These are appeals from a decree of the District Court in an action brought by Minerals Separation, Limited, a corporation of Great Britain, against the Miami Copper Company, a corporation of Delaware, charging infringement of United States Letters Patent No. 835,120, issued to Sulman, Picard and Ballot, November 6, 1906; No. 962,678, issued to Sulman, Greenway and Higgins, June 28, 1910; and No. 1,099,699, issued to Id. Greenway, June 9, 1914, and owned by the plaintiff.
Of the cláims in suit the court found claims 1 and 12 of the first patent valid and infringed, and claim 9 invalid; claims 1, 2, 5 and 6 of the second patent valid and infringed; and claims 1 to 12 of the third patent invalid. The decree being in parts adverse to both parties, both appealed, presenting for review the same claims, excepting claim 9 of patent No. 835,120, with respect to which the appeal is abandoned.
As both parties are appellants, we shall speak of them as they stood in the court below.
The three patents in suit, to which we shall refer in the order of their issue as first, second and third, are for processes relating to water concentration of ores. They have for their object, stated generally, the separation of metalliferous matter from gangue or barren matter in ore pulp, by means of oils, fatty acids or other substances which have a preferential affinity for metal over gangue. The first patent, while employing the known selective affinity of oil for metal, is based upon a discovery that that affinity is greatest and metal recovery highest when the proportion of oil to ore is relatively least, and upon the disclosure that that property or characteristic may be brought into action and commercially utilized by agitating the ore-bearing pulp until a foam or froth arises to the surface, carrying with it and holding for recovery the extracted metal.
The process of the second patent is distinguished from the process - of the first in that the frothing agent is soluble and develops in solution (when agitated to a froth) a selective affinity for metal similar to that of oil, the insoluble frothing agent of the first patent.
The characteristic of the process of the third patent is that concentration may be effected in the cold and without the aid of acid by the admixture of an aromatic hydroxy compound such as phenol or cresol in the place of the insoluble and soluble frothing agents of the other patents and by agitation of the pulp to a froth.
We are aware that this very brief statement of the distinguishing features , of the three patents is technically inadequate and will be understood only by those familiar with the history and development *754of the art of ore concentration. As that art has been extensively considered and elaborately discussed by scientists and courts both in this country and abroad in cases in which the invention in suit was involved,1 we shall not make even a summary of the art or rehearse the history of this litigation as it has progressed in widely separated parts of the world, but shall rather adopt the whole litigious literature of the invention as matter preliminary to the consideration of the particular issues in this case, repeating only so much as may be necessary to-throw light on this new chapter..
First Patent.
[1] The invention of the first patent in suit is based upon a discovery of an wholly unexplained phenomenon arising from the agitation of ore pulp containing oil and air in certain proportions. This was a discovery in an art in which it was well known that the elements of oil, air and agitation possessed certain characteristics and produced certain results.
Haynes in British patent No. 488 of 1860 first suggested the use of oil in water concentration of ores by pointing out the affinity which oils have for metallic substances in preference to gangue. Carrie J. Everson showed by Letters Patent No. 348,157, that a small quantity of acid in the pulp aids oil in distinguishing between metal and barren material with which it comes in contact. Elmore (Letters Patent No. 676,679), Kirby (Letters Patent No. 809,959), Froment (British Patent No. 12,778 of 1902), Cattermole (Letters Patent No. 763,260), Sulman and Picard (Letters Patent No. 793,808), and others, employed the known affinity of oil for metal in ore concentration processes by using oil in proportions varying from 2 per cent, to 300 per cent, on the ore and recovering the oil-coated metal particles by causing them to rise to the top or sink to the bottom of the pulp.
Agitation of oil-impregnated pulp was old in the art. It was employed by Haynes, Everson, Cattermole, Froment, and Sulman and Picard. In these processes, agitation was either gentle or thorough, but never great, and while always employed to produce a thorough oiling of the metal, it was used in different degrees for the sole purpose of causing the metal particles to rise or sink.
Air and other gases were also known and were developed in the form of bubbles to supplement the natural buoyancy of oil and to assist *755the oil-coated particles to the surface. This use of air was disclosed by Proment in 1502 and again by students of the University of California in the California Journal of Technology in 1903, and by Sul-man and Picard in the patent referred to (No. 793,808), commonly called the Bubbles Patent.
Thus it may be stated generally that in the prior art, oil was used for its known selective affinity for metal, agitation to mix the oil with the metal, and air to supplement the buoyancy of oil in raising oil-coated metal particles to the surface. To this extent had the art of oil flotation advanced when the patentees entered it, having reached the commercial stage in only two processes, Elmore and Cattermole, representing respectively metal-flotation and metal-sinking processes, and having reached the stage of success in none.
The Elmore process was known as the bulk-oil or oil-buoyancy process. It required from 100 per cent, to 300 per cent, of oil on the ore, that is, from 2,000 to 6,000 pounds of oil to 2,000 pounds of ore, and called for a gentle movement or agitation of pulp in a way that would bring the oil and metal in contact without breaking the oil bulk, and relied for metal recoveries on the buoyancy of the oil (due to the lesser specific gravity of the large volume) to raise and hold on the surface the metal which by affinity it had extracted from the ore. This was an oil-flotation process. It was not successful because the cost of the considerable quantity of oil used and not recovered made its practice commercially prohibitive.
The Cattermole process was just the reverse of Elmore. While this process depended upon the utilization of the same selective affinity of oil for metal, the quantity of oil was relatively small, being from 3 to 6 per cent, on the ore; but the agitation was considerable, having for its object not the retention of the oil in bulk as in Elmore, but its separation and thorough distribution through the pulp, with the object and result of causing the metal particles to be brought together and agglutinated with the metal slimes, forming granules of a size and specific gravity sufficient to cause them to sink, where they were recovered while the gangue was carried off the surface by an up-flow. This was the metal-sinking process. It had a doubtful success in the concentration of copper and zinc ores of high metal content, but like the Elmore process it was impracticable because unprofitable for the concentration of ores of medium and low grades.
It was while the patentees were engaged in developing this process with a mechanical appliance known as a Gabbett Mixer, by which the pulp was agitated, that the discovery of the. first patent was made. It was found that when the proportion of oil was reduced below 2 per cent, the agglutination of Cattermole ceased, and metal recoveries ceased also. This so disturbed the theory upon which the patentees were working that they at once embarked on a series of experiments, in which the quantity of oil was progressively reduced from the Catter-mole proportion and the agitation varied in intensity and duration. In experiments with oil in proportions just under the Cattermole proportion nothing resulted. The Cattermole concentration was lost and no other concentration was obtained. When in the line of experiments, *756the proportion of oil to ore was reduced to 1.5 per cent., a “float” appeared. At 1.04 per cent, “still more float” appeared. At .32 per cent, the “float vastly increased.” At .10 per cent., the float again “vastly increased.” It thus developed that in using oil at .10 per cent, or even at .05 per cent, on the ore, and after violently agitating the pulp from two and one-half to ten minutes, there arose to the surface when the pulp was brought to rest a thick froth or foam of oil-coated air bubbles carrying oil-coated metal particles to the extent of about 90 per cent, of the metal content, the foam being sufficiently stable to permit removal and metal recoveries.
This was an entirely new result based upon a phenomenon then unknown and still unexplained. It constituted discovery. It was a discovery that promised what has since been accomplished — -a change in the art of oil flotation from laboratory experiments and mill failures to commercial success. Its great value especially in zinc and copper ore concentration met with world-wide recognition. The art immediately adopted it and paid tribute to it, either by yielding to the patents covering it or by challenging them in litigation commensurate in scope and importance with the field of the discovery itself. The grounds upon which the validity of the patents was attacked were, first, that the phenomenon was already known, and second, that the patents disclosed no novel means for reducing it to practical use. With the decision of the Supreme Court sustaining the validity of the patent, the two grounds of attack disappeared, leaving open, however, the question whether the discoverers have wholly covered their discovery by a patent, and if not, then how far have they appropriated it to their exclusive use, within, the principle that in its naked sense a discovery is not patentable and can be embraced in and controlled by a patent only when and to the extent that its principle is developed into invention by the disclosure of a medium or means which brings it into practical action. Morton v. New York Eye Infirmary, 5 Blatchf. 116, Fed. Cas. No. 9,865.
The particular medium by which and through which the discoverers brought into practical action and put to practical use the principle of their discovery, is a process disclosed in their patent. The process described by the claims in suit, including the elements we have numbered and the distinguishing features we have italicized, is as follows :
“1. The herein-described process of concentrating ores which consist (1) in mixing the powdered ore with water, (2) adding a small proportion of an oily liquid having a preferential affinity for metalliferous matter (amounting to a fraction of one per cent, 'on the ore), (3) agitating the mixture until the oil-coated mineral matter forms into a froth, and. (4) separating the froth from the remainder by flotation.
“12, The process of concentrating powdered ore which consists in separating the minerals from gangue (1) by coating the minerals with oil in water containing a fraction of one per cent, of oil on the ore, (2) agitating the mixture to cause the oil-coated mineral to form a froth, and (3) separating the froth from the remainder of the mixture.”
The claims disclose the process. The specification, as usual, throws light upon the process by.distinguishing it from the prior art, describ*757ing its operation and result, and referring to illustrations of its practice in two apparatus, in one of which agitation and consequent aeration and fomentation are accomplished by mechanical means.
The validity of this patent and of its equivalent abroad has been widely attacked and ultimately sustained. As our task is to interpret the scope of the United States patent we shall concern ourselves only with the decisions of the courts of this country.
The first suit on the patent was brought in the District Court of the United States for the District of Montana. Minerals Separation, Ltd., v. Hyde, 207 Fed. 956. The validity of the patent was attacked on the ground of anticipation by the prior art, but the court held the patent valid and found invention in the novel and useful combination of oil, air and agitation. Minerals Separation, Ltd., v. Hyde, 207 Fed. 956, 961.
The United States Circuit Court of Appeals for the Ninth Circuit, reversing on appeal the decree of the District Court, found the patent invalid, on the ground that its only novelty lay in the reduced quantity of oil, that this was an improvement only in degree and therefore did not involve invention. Hyde v. Minerals Separation, Ltd., 214 Fed. 100, 130 C. C. A. 576.
The case was then removed by certiorari to the Supreme Court of the United States, and while there awaiting hearing, the action at bar was instituted in the District Court of the United States for the District of Delaware. Minerals Separation, Ltd., v. Miami Copper Co. (D. C.) 237 Fed. 609.
In this case the District Court held the patent, valid and infringed, finding (in opposition to the Circuit Court of Appeals for the Ninth Circuit) patentable invention in the use of oil in the minute proportion of the patent.
Shortly thereafter the Supreme Court heard argument and entered a decree in Minerals Separation, Ltd., v. Hyde, 242 U. S. 261, 37 Sup. Ct. 83, 61 L. Ed. 286, by which it reversed the decree of the Circuit Court of Appeals for the Ninth Circuit and held the patent valid, finding invention, as we read the opinion, in the co-action of the critical proportion of oil and air effected by “an agilation greater than and different from that which had been resorted to before,” resulting in a froth concentrate of economical vahte.
Following the decree of the Supreme Court in Minerals Separation, Ltd., v. Hyde, this case was argued before us. The decree of the Supreme Court, with its accompanying opinion in the Hyde Case, materially changed the aspect of this case on appeal by contracting, and in a sense expanding, the issues as tried by the District Court. It disposed of the issue of validity, which had been vigorously contested in the court below. But in disposing of that issue upon grounds different from those upon which the District Court based a like judgment, the question of infringement was acutely enlarged. Upon the finding by the District Court that patentable invention resides in the critical proportion of oil, the admitted use of oil in that proportion by the defendant was manifestly controlling in its finding of infringement, although the defense extended to the whole of the defendant’s practices. But under the finding by the Supreme Court in the Hyde Case *758that invention resides not alone in the critical proportion of oil but also in air and agitation, we are called upon to construe the patent in the light of that finding and determine whether the defendant’s practices of aeration and agitation in connection with its admitted use of the critical proportion of oil, are within or beyond the scope of the patent.
It is to be noted and kept in mind that the Supreme Court did not construe the patent or determine its scope, for it had no occasion to do so. In the case before it, infringement was so clear that it had to be found if the patent was valid. The validity of the patent, therefore, was the' only seriously controverted issue before the Supreme Court.
In deciding the issue of .validity, the Supreme Court disposed of the prior art as anticipations by reviewing by general classification its processes together with the process of the patent, and in so doing used expressions which the parties have severally employed in support of and in opposition to their respective contentions. The plaintiff maintains that the language of the Supreme Court supports its broad contention, that:
“Whenever the modifying agent of the patent (oil) is used, a person infringes who gets air into the pulp in any fashion and agitates the mixture by any means to a sufficient extent to cause the mineral particles to attach them'selves to air bubbles and to rise therewith above the top of the mixture in a collection of bubbles and metal particles, to wit, froth.”
The defendant maintains that the agitation, in which the Supreme Court found invention, is agitation produced by mechanical means, and that any one, who, though using tire modifying agent of the patent in the critical proportion, introduces air into the pulp otherwise than by beating it in, and who agitates the pulp to a metal-bearing froth by any means other than mechanical, or who otherwise obtains the result without any agitation whatever, is beyond the scope of the patent and escapes infringement.
Considered in the light of what the Supreme Court said and what it did not say, it is clear that the positions of both parties are extreme. The contention of the plaintiff at least omits the very definite limitation of the patent to the, results obtained by the use of oil within the described proportions, and also the equally definite disclosure of an agitation in violence and duration greater than before employed, while the defendant misinterprets words of description as words of limitation.
The Supreme Court said that:
“The process of the patent in suit, as described and practiced, consists in the use of an amount of oil which is ‘critical’ and minute as compared with the amount used in prior processes * * * and in so impregnating with air the mass of ore and water used by agitation — ‘by beating the air into the mass’ as to cause to rise to the surface of the mass, or pulp-, a froth, peculiarly coherent and persistent in character. * * * ”
By this expression the defendant maintains that the Supreme Court did not merely repeat testimony describing and showing how the process was practiced, but used the words as their own, and thereby interpreted the patent and limited its scope to the introduction of air into the pulp “by beating the air” into the pulp by the specific mechanical means illustratively shown by the drawings of the patent. We *759do not so interpret this expression. In the first place the patent nowhere uses the words “by beating the air into the mass.” Therefore these words, as quoted by the Supreme Court, were not quoted from the'patent, but were taken from the testimony of a witness who used them in describing the process as discovered and developed by the patentees. This being so, we do not think these words, as used by_the Supreme Court in describing the process, can be construed as a limitation upon the process.
It further appears that the Supreme Court, in distinguishing the process of the patent from processes of other patents relied on as anticipations, found that the lifting force which separates metallic particles of the pulp from other substances resides chiefly “in the buoyancy of the air bubbles introduced into the mixture by an agitation greater than and different from that which had been resorted to beforeBy this expression the defendant insists that the court explicitly limited the patent to agitation caused by mechanical means, thereby excluding from its scope such agitation by pneumatic means as was used in part in the defendant’s practice. As this expression is susceptible of an entirely different meaning, presently to be considered, we find nothing said by the Supreme Court which indicates that it limited the agitation of the patent to agitation by mechanical means.
The defendant further maintains that the Supreme Court gave to the patent a narrow construction when it used these words:
“While we thus find in favo? of the validity of the patent, we cannot agree with the District Court in regarding it valid as to all of the claims in suit. As we have pointed out in this opinion, there were many investigators at work in this field to which the process” of the patent “in suit relates when the patentees came into it, and it was while engaged in study of prior kindred processes that their discovery was made. While the evidence in the case makes it clear that they discovered the final step which converted experiment Into solution, ‘turned failure into success’ (The Barbed Wire Patent, 143 U. S. 275 [12 Sup. Ct. 443, 36 L. E.d. 154]), yet the investigations preceding were so informing that this final step was not a long one, and the patent must bo confined to the results obtained by the use of oil within the proportions often described in the testimony and in the claims of the patent as ‘critical proportions’ amounting to a fraction of 1 per cent, on the ore. * * * ”
We are inclined to the opinion that by this expression the court intended a limitation only upon that one feature of the patent to which the expression was addressed. The District Court had held valid certain claims in which the proportion of oil was described simply as “a small quantity,” and the Supreme Court in reversing that finding and holding those claims invalid, used the quoted words of limitation in confining the patent to the results obtained by the use of oil in the critical proportions of less than 1 per cent.
From this recital of the litigation of the invention of the first patent it appears that in construing the claims of the patent we are greatly aided by the opinion of the Supreme Court in being told with authoritative finality that the process involves invention and in being shown in which of its elements invention resides; but it is equally clear that in determining the breadth and scope of the claims, we are without the aid of any adjudication in which their scope has been decided or even considered.
*760The elements of the patent in which invention is found are oil, air and agitation. These were old in the art, possessing as we have shown, known characteristics and functions, and had they performed in the process of the patent no new or different function or had they produced no new or different result, it is clear they would have anticipated the patent and defeated its claim to invention. But a finding by the Supreme Court that the invention was not anticipated by the old uses and results of these elements is in effect a finding that these elements as used in the process of the patent perform or develop new uses and functions or produce different results. And such we find to be the fact.
The invention, as we have said, is founded upon a discovery. Its patentability depends upon the medium disclosed in the patent by which the force or principle of the discovery is brought into action. Three new uses of old elements are disclosed by the- patent, producing a new result. The first relates to oil.
The affinity of oil for metal was known, and though old, was employed in the invention; but that this affinity in a given condition is greatest when its quantity is relatively least or that the affinity increases with the decrease of oil below a given quantity (less than 1 per cent.) is tire soul of the discovery and was wholly new. But the discovery did not consist of this alone. The newly discovered phenomenon of the minute quantity of oil is not a chemical phenomenon. Oil in pulp in 'minute quantity if inert and left alone will do nothing and produce nothing. Something must be done to develop it. The phenomenon not being susceptible of development by chemical change, is developed by physical change of the pulp. As a medium or means of producing that change and creating the condition under which the phenomenon arises, the patentees pointed out — agitation.
The agitation of the patent does several things, old and new. It mixes the oil with the metal of the ore. This is old. Then by its greater intensity and longer duration it stirs the pulp into a froth, developing at once its own new use as a frothing means and still another new function of oil — that of a frothing agent. Both are new.
But froth is made of air as well as oil. Air in bubbles is used for its old function of assisting or escorting metal particles to the surface. But it is also used for the entirely novel purpose of supplying one of the essential elements of froth, froth being the new result intended.
Thus oil is used for its newly discovered characteristics of greater metal affinity when in minute quantity and for its new function as a frothing agent; air for the new purpose of supplying an element of froth; and agitation for its new purpose of bringing the two together and causing them to co-act and produce the new result of a metal-carrying froth. In other words, in so employing these old elements for new purposes, the new things which the patentees told the art are that a radical decrease of oil in conjunction with a radical increase of agitation, develops to its highest potentiality the known affinity of oil for metal and produces a physical change in the pulp in the form of a froth by which metal recoveries are made possible and commercially profitable. The importance of these disclosures, scientifically and commercially, is manifest.
*761In approaching' a consideration of the scope of the patent, we lay aside those features of the discussion in which the plaintiff demands by broad construction the highest reward for a great contribution to a feeble art, and in which the defendant, contending for a narrow construction, emphasizes the servitude of a great art to a patent monopoly. The rights of an inventor and of an art in an invention are established by law and are not affected by other considerations. Speaking generally, the statutes give an inventor a patent monopoly of his invention to the extent of his patent disclosures, and to that extent the art is servient to his monopoly. Everything touching the invention not disclosed by the patent is free to the art without regard to the value of the inventor’s contribution. So the question of law in this case, involving as it does large interests and perhaps far-reaching commercial results, is no different from similar questions constantly appearing in controversies of smaller compass. The question simply is whether certain practices come within the scope of the patent claims. But the question of infringement has grown far beyond the borders of the case and we are really asked both by the plaintiff and defendant to determine the scope of the patent in such terms as will inform the art as well as the owners of the patent the precise field covered by the patent and the extent of the field left free to the art. Such a decision to be useful must of course be predicated upon facts that make it legally possible, for otherwise we encounter the futility and the mischief of construing- a patent in general terms and without reference to the oc ■ casion or tiling which calls for its interpretation. To avoid this error we shall confine ourselves to the precise issues of this case as developed by the evidence, and without regard to other considerations we shall construe the patent with reference to the particular practices which are represented by one party to be within its scope and by the other to be beyond it.
The defendant practiced four processes of ore concentration, using in all the fomenting agent of oil in the critical proportion of the patent. Two processes were practiced before suit was instituted, the third during the progress of the trial, and the fourth after the record had been completed and the trial closed. As the infringement found by the decree relates to the processes appearing in the record, only those processes are before us on appeal.

First Process.

The defendant company owns and operates a large porphyry copper mine at Miami, Arizona. The ore is low grade and of a kind peculiarly responsive in concentration to the process of the patent.
The defendant employed a metallurgical mining engineer to develop and install in its reduction works an oil-flotation concentration plant. The engineer made repeated visits to the mill of a neighboring copper company, a licensee of the plaintiff, studied the process of the patent there in practice, and reproduced it in the mill of the defendant. This was a small plant, of a capacity o f but two tons per hour or forty-eight tons per day, operated during the period from December, 1913, to August 5, 1914. It was used evidently more as a testing or experimental
*762plant for another process then being developed than for commercial purposes.
This constituted the defendant’s first process, and as infringement was not disputed, we affirm without discussion that part of the decree holding infringement by this process.

Second Process.

. On August 7, 1914, two days after the discontinuance of the first process, the defendant started its second process in a plant which it had constructed during the practice of the first. This plant may best be understood by a diagram furnished by the defendant and by its own detailed description of its operation appearing in its brief:

“Ttie material treated in the flotation plant at Miami is received through the launder or trough A, the samé bearing the legend ‘Original Pulp Feed.’ This material is a freely flowing pulp, and flows into the box or tank B, upon which the following inscription appears. ‘Sump from Which Pulp is Pumped.’ The oil or other modifying agent is supplied to the pulp through the pipe L, marked ‘oil feed.’ A centrifugal pump 0 raises the pulp from the sump B, and forces it upwards through a pipe D, from which the piulp passes into an inlet funnel B. The pulp flows from the funnel B downward through a pipe F and enters the Pachuca tank G through the side thereof, as shown in the drawing. A small air pipe H extends downwardly front the top of the Pachuca to a point near the bottom thereof, where it delivers an air jet at the point designated I. The small air pipe II is surrounded by a larger pipe J, open at both ends. There is an annular space between the pipes H and J, and the air entering the lower end of the large pipe ,/, through the pipe II, permeates the pulp contained in the pipe J with small bubbles, which have the effect of forming a mixture of air and pulp of lower specific gravity than the *763pulp alone. The lightened column of air and pulp in pipe J risos and is projected against a conical deflector K, and then falls into the main body of the Pachuca. The circulatory movement of the pulp in the Pachuca tank has the effect of thoroughly mixing the oil with the pulp. The pulp flows from the top of the Pachuca tank into a box M, whence it is conducted by the launder or trough N to the air cells, marked 1, 2, 8 and 4-
“The air cells 1, 2, 8 and 4 are similar in construction. The bottom of each cell consists of-four piles of canvas, beneath which are eight air compartments, separate and distinct from each other, extending in a series from end to end. The canvas bottom: of the machine is inclined, thus making the cell deeper at one end than at the other, and it is for the purpose of getting an even distribution of air that the eight compartments are used, it being obvious that if there were a single air compartment most of the air would escape at the shallow end, where the water pressure is least. Air under slight pressure is supplied to the compartments beneath the cells 1, 2, 8, 4 and 5, by means of a blower designated by the letter M upon the drawing. The air is conducted through a pipe marked ‘Air Main’ from' the blower, and branch air pipes, shown most plainly at the right of cell No. 1, conduct the air to the several compartments beneath the cells. The degree of air pressure necessary is quite slight, and, as stated by Mr. Yerxa, it is necessary to use merely enough pressure to overcome the hydrostatic head of the pulp and to force the air through the permeable medium, that is, the canvas bottom.
“The air so pumped beneath the canvas bottoms of the cells 1, 2, 8, 4 and 3 passes upward through the pores of the canvas into the pulp, and the bubbles rise through the pulp in a manner similar to the rising of the bubbles through a glass of carbonated water.”
For the purpose of this discussion, the details of the apparatus and of its operation, may be simplified by referring to its four essential parts: C, centrifugal pump; B, a break or open space between the pipe of the pump and the Pachuca tank which does not appear on the diagram or in the defendant’s account of the operation; G, Pachuca tank and its appliances; and 1, 2, 3, 4 and 5, Callow cells.
Before following the steps or rather the flow of the defendant’s process, we should have in mind the theory of its practice. The defendant maintains that the process of the patent is “an agitation froth process,” that is, a process by which the desired metal-bearing froth is obtained by agitating pulp containing the critical quantity of the frothing agent (oil) “to cause” the froth to arise or “until” a froth is formed. It says that its process, in contradistinction to the process of the patent, is a “bubbles process” (containing the same critical quantity of the same frothing agent), by which air, introduced into the pulp from below, passes through the pulp “without any agitation whatever,” and arises to the surface in short-lived evanescent metal-bearing hubbies forming a “foam.” It maintains that by introducing air into the pulp by sub-aeration it produces a foam or froth otherwise than by agitation, that nowhere in the process is there agitation, or that, at most, there is only such agitation as appears in the prior art.
Agitation “to cause” a froth or agitation “until” a froth is formed, being the disclosed means of the patent to produce the phenomenon of the critical quantity of oil, and aeration without agitation being the defendant’s claimed means of causing or obtaining the same phenomenon from the same critical proportion of oil in the form of an evanescent foam, the controversy revolves around the elements of aeration and agitation.
*764C. Centrifugal pump. The first step in the defendant’s process was a centrifugal pump. The defendant claims its one function was that of lifting the pulp (containing oil in the critical proportion of the patent) from one floor of the mill to another, and that in doing so the pulp was neither agitated nor aerated. Opposed to this contention and to the testimony supporting it was testimony that a centrifugal pump drawing air and liquid was the most common type of agitator and aerator of the cyanide art before the Pachuca tank was invented; that in the defendant’s apparatus, air was drawn with the liquid into the pump in large quantities; and that in revolving at the rate of 850 revolutions per minute the pulp was violently agitated and measurably aerated.
Reconciling the conflicting testimony as best we may, we are forced to the conclusion that the pump revolving at the rate of 14 revolutions per second could not well avoid agitating the liquid it hoisted; that the agitation was violent; that air was drawn in with the liquid and that to an extent the pulp was aerated within the sense of the agitation of the patent and also by the very mechanical means or its equivalent to which the defendant insists the patent is limited.
B. Break in the circuit. At the point B in the pipe between the pump and the Pachuca tank there was a break not appearing in the diagram, permitting the pulp, arising from the pump in its agitated and partially areated state, to drop for a space through the air into a larger pipe, whence it was carried to the Pachuca tank'. While this was not a prominent feature of the defendant’s process it was of sufficient consequence for the defendant to use it. It had the effect of producing further agitation of the pulp in its fall and further aeration arising from that agitation. It was known as splash agitation, its principle appearing in the early attempts to purify water by aeration. We are satisfied that this constituted agitation and aeration by agitation, and again by mechanical means to which it is sought to limit the patent.
G. Pachuca tank. The pulp twice agitated and aerated was then carried without stopping into a Pachuca tank. This appliance, briefly described, is a tank 18 feet 6 inches high by 4 feet in diameter. Descending in its center are two pipes or columns, one within the other, and in operation compressed air is released through the inner one, sending the fluid in an upward current through the outer one until it strikes with force an overhanging cone or umbrella, which causes it to splash and fall back into the tank, to be subjected again and again to the same revolving movement for a period of time measured by minutes.
The Pachuca tank was taken from the cyanide art, where its one function was agitation and aeration, or rather aeration by agitation. Although agitation is denied by the defendant to be a part of its process, it cannot be seriously contended in the face of the testimony and of the demonstration of the action of the Pachuca tank before us, that the force of compressed air to which the pulp in the tank is subjected, does not cause agitation and véry violent agitation.
But the defendant contends that the agitation of the patent is lim*765ited to agitation occasioned by mechanical means, and as the agitation in the Pachuca tank is caused by pneumatic means, it is beyond the scope of the patent. This contention is based not alone upon the words of the Supreme Court which we have already discussed, but upon the relation of a mechanical device to the discovery of the invention.
It appears that in the experiments in which the discovery was made, the inventors agitated various mixtures by an apparatus known as a Gabbett Mixer, and when they came to reduce their discovery to invention and patent it they illustrated diagrammatically “one form of apparatus suitable for carrying this invention into practice,” which included such a mixer. The patentees did not attempt to patent a mechanical means by which their process could be practiced. This is obvious, for the means illustratively shown was a mechanism already patented (No. 444,345, Gabbett Mixer 1891). Nor did they attempt or intend to limit their patent to any mechanical means. Their patent was for a process. But without regard to their intention, did they in fact so limit it? That depends upon what they disclosed by their patent.
By their disclosures they first told the art that a maximum metal recovery could be had from a minimum oil content. Up to the time of this disclosure that was an unknown phenomenon. But this disclosure alone, interesting as it was, would have been valueless to the art, and would not have entitled the discoverers to a patent, until they told how and by what medium that phenomenon could be brought into practical use. Knowing this, they then told the art by the same disclosures that the minute quantity of oil, besides possessing an affinity lor metal, was a frothing agent, and when used as such the phenomenon appeared in the froth it developed. But the patentees did not stop with the disclosure that fomentation is the condition out of which the phenomenon arises, but proceeded by further disclosures to tell the art that the wav to produce the desired fomentation is by agitating the pulp containing the frothing agent. But agitation of certain kinds for certain purposes was well known, so they went further and told what was not known, namely, that the agitation requisite to fomentation of the character desired, is agitation “greater than and different; from that which had been resorted to before,” that is, greater than the more or less brisk or vigorous test-tube agitation of early patents and of the Cattermolc process, and different from the revolving gentle agitation of the Elmore hulk-oil process, and that it must be violent in character and extended in duration in order that air (the other element of fomentation) might he brought into the fluid and into co-action with the minute quantity of the frothing agent. They thus disclosed not only agitation but the kind of agitation as the medium or means by which the principle of their discovery could be reduced to practice. Agitation was thus made the practical element of their patented process, and by their patent disclosures they told the art that agitation was the secret by which the principle of their discovery could be unlocked and used.
If the same principle can be turned to use and the same results ob - tained without agitation, or by an agitation which is not the equivalent *766of the agitation of the patent disclosures, we may have another question; but when the critical quantity of oil is used and fomentation is produced by agitation, which in degree of violence and in duration is substantially that of the patent, clearly it is indifferent whether it is attained by mechanical or other means, for the patent deals with agitation as a means of developing the discovery, not with means for developing agitation.
Accepting the teaching of the patent with reference to agitation as a means, the defendant employed it, certainly in three, if not in four, of the steps of its process. In the first and second, agitation was obtained by mechanical means; in the third (the Pachuca tank), by pneumatic means. It is upon this difference in means to produce agitation that the defendant, in part, defends the charge of infringement. But what it sought and what it got by the use of the Pachuca tank was agitation, and that is what the patent told it to get, and we conceive it makes no difference whether it got it by mechanical or pneumatic means. We see no difference between the blow of a paddle and the blow of a blast of air as means to produce agitation. And the defendant itself shows there is no difference between the two in procuring the agitation of the the patent, for by agitating the pulp in the Pachuca tank by pneumatic means with an intensity and for a period of time sufficient to aerate the pulp, the defendant got the precise metal-bearing froth of the patent. This was unintentionally and accidentally shown on one occasion when the Pachuca tank was cut out of the process and the pulp brought to rest. The characteristic froth of the patent arose at once and formed in a collar two feet thick. In view of the agitation to which the pulp had been subjected, we must assume that it was the result of that agitation.
Thus far the defendant did everything that is disclosed by the process of the patent. It used the critical quantity of oil. This is admitted. It agitated the pulp by one means and another with an intensity and for a time sufficient to change the physical character of the pulp, as intended by the patent, and developed in it the quality of producing an air-bearing froth, which it did when permitted to come to rest. But in the practice of the defendant, agitation was not stopped or even arrested in the Pachuca tank. The pulp was carried in circuit without stopping and withou't abatement of agitation into Callow cells, carrying with it the air content accumulated by the agitation of the centrifugal pump, the air drop and the Pachuca tank.
1, 2, 3, 4, 5. Callow cells. As a last step, the pulp was conveyed into Callow cells. A Callow cell is a rectangular tank with a sloping bottom made of canvas, through the perforations of which compressed air ascends in myriads of air bubbles through the liquid it contains. By this process, the defendant contends it pursued a practice taken from the prior art and entirely outside the scope of the patent.
In this connection much stress has been placed by the defendant upon the prior art, on the theory that as the Supreme Court found the invention not anticipated, all that the prior art contains is open to it. without the hazard of infringement. This position is unobjectionable. *767It is clear that if the defendant practiced the process of the patent and obtained a different result, or if it practiced a different process and obtained the same result, it did not infringe. To do this it was free to resort to a practice of the prior art or to a. practice new' to the art. It chose to rely upon a practice of the prior art, which, though producing the same result in metal recoveries as that of the patent, it maintains differed from it in its steps and means. It was based upon Patent No. 793,808 granted to Sulman and Picard (two of the pat-entees of the patent in suit), and commonly called the Bubbles Patent. This patent, though it never reached the mill, has been extensively discussed by experts and counsel. Air is introduced into the bottom of a tank similar in shape to that of a Callow cell. Near the bottom is a perforated helical worm or tube, through which, while revolving, air is permitted to escape and ascend in bubbles to the surface. As the pulp is modified by oil (not the critical quantity of the patent) the air bubbles and metal particles are coated with oil, whereupon the oil performs its known affinity for metal and air its known characteristic to ascend and assist the oiled metal to the surface.
While there is a similarity in principle between the mere introduction of air in the Callow cell and in the Bubbles tank, the purpose for which air is injected and -the function which air performs after it is injected arc altogether different in the two. Before the pulp is put into the Bubbles tank it is agitated for the purpose of mixing the oil and coating the metal particles, and when that is done it is turned into the Bubbles tank where the air bubbles, liberated through the perforations of the coil, attach themselves to and escort the oil-coated metal particles to the surface, where they are carried off by skin flotation. In the Callow cell of the defendant’s process (the claimed equivalent of the Bubbles tank) air was used for another purpose. The pulp first agitated to the potentiality of the critical quantity of oil and air of the patent was carried into the Callow cell, and with its elements thus fully developed was subjected to an air blast, which did two things, resulting in a third. First, the air blast further aerated or super-aerated an already fully aerated pulp by driving into it myriads of air bubbles, and second, caused an agitation which while considerable was not violent, resulting in a foam, which persisted so long as air pressure was maintained, and which had a metal-bearing quality and sufficient stability to permit recovery by overflow.
A peculiar feature of this step in the process and upon which the defendant earnestly relies to distinguish it from that of the patent, is, that if the pulp agitation of the Callow cell is arrested by withdrawing the air pressure, the foam immediately subsides and the froth of the patent does not arise as it did when agitation was arrested in the Pachuca tank. This is true. It is equally true that in this fourth step, aeration is direct and is not the result of or caused by agitation. On the contrary, agitation results from aeration, and such agitation, though present in some measure, is not even approximately of the violence and duration of the agitation of the patent. The operation in the Callow cell certainly possesses these distinguishing features *768from operation of the process where aeration is caused by agitation. Emphasizing this difference in its favor, the defendant pressed further and urged that the operation of the Callow cell was not dependent upon the precedent treatment of pulp in the Pachuca tank, and that the same results could be obtained from the Callow cell without such previous agitation and aeration. This assertion is based upon an experiment made by the defendant in the presence of representatives of the plaintiff when the Pachuca tank was cut out of the system and pulp from the centrifugal pump was shunted directly into the Callow cells, with the result that the Callow cells continued to perform their function of supplying air babbles, agitating the pulp to a degree and forming an overflowing metal-carrying foam. But the metal carried over was not assayed and we do not know what were the commercial results of the test. We know, however, that this was but an' experiment and after the experiment had been concluded, the defendant returned immediately to its practice of using the Pachuca tank. Nor are we informed as to what would happen if the centrifugal pump had also been cut out, because whether in the mill or in the laboratory, so far as we have been shown, it appears that before the Callow cell (or Bubbles tank) is called upon to perform its task, the pulp is always pre-agitated and pre-aerated in some fashion and to some extent. Even in the demonstrations of the Callow cell and the Bubbles tank made before us in court, the defendant’s demonstrator caused the pulp to be violently agitated by a Gabbett Mixer, the illustrated means of the patent, for a period of time measured by a stop-watch before it was turned into the cell and tank.
[2] Notwithstanding the defendant’s testimony is silent as to what a Callow cell would do to pulp that had not been previously agitated and aerated, and notwithstanding all Callow cell demonstrations before us were made with pre-agitated and pre-aerated pulp, the case for the defendant was largely argued as though its process consisted solely in passing thoroughly mixed but quiescent pulp directly into Callow cells, where it received its first and final aeration without previous or present agitation, resulting in a metal-bearing foam with characteristics different from those of the froth of the patent. We find nothing in the evidence or in the demonstrations which justifies that argument. If the only agitation to which the pulp was subjected (after such agitation as in the prior art was necessary to mix the oil and ore) was the agitation of the Cállow cells, we would not say that that agitation amounted to or was the equivalent of the violent agitation of the patent disclosure and constituted infringement; but in the process we are considering and upon which the decree we are reviewing was based, the Callow cells were not the whole process but were merely the last of four distinct parts of the process, the other three being the process of the patent or its fair equivalent. Having used the process of the patent in the first three steps in developing in the pulp the potentiality of the critical quantity of oil and air and in bringing the pulp to the point where, if permitted, it would produce the result of the patent, we feel that the defendant cannot escape infringement by taking an additional step, even though that step if taken alone avoids tire patent.

*769
Third Process.

The third process of the defendant was developed and put into practice during the trial and constituted one of the defenses to the charge of infringement. There is little difference between it and the second process. It is shown by the accompanying reproduction of a blueprint of the apparatus in which it was practiced:
Blue Print of New Miami Mill.

*770The plant is shown to comprise two independent sets of flotation cells, one at the right and the other at the left of the drawing. The flotation cells are designated: “4. Roughing Cells” and “2. Cleaner Cells.” Adjoining each group of cells is a Pachuca tank. The operation begins upon the 22 concentrating tables, so numbered upon the drawing. The material rejected by these tables is treated by the flotation process. The flow of pulp in the tables through the launders takes place by gravity until the pulp reaches a bucket elevator, which is the* substitute for the centrifugal pump in the second process. When the pulp is raised by the elevator to an upper floor it is divided and flows in equal parts into two Pachuca tanks, thence to the Callow cells, where metal recoveries are obtained by froth overflow.
The value of this process, as a defense, is found in an experiment to which it was subjected. The plant was arranged in two groups of identical members. In the experiment, one group was operated with the Pachuca tank as planned. In the other, the Pachuca tank was cut out and the pulp conveyed directly from the elevator to the cells. The result was no apparent difference in the action of the pulp and little difference in the assays of the metal recoveries, that difference, curiously enough, being in favor of the group in which the Pachuca tank was not used. The evidence of the fact and of the effect of this experiment was not contradicted, except, perhaps, by the defendant itself, by returning at once to its previous practice of using both Pachuca tanks, and in pursuing that practice to a time beyond the trial. This fact places tire third process in the position of the second, where we have found that agitation and aeration of the Pachuca tank is the agitation of the patent, and amounts to infringement.

Fourth Process.

The fourth process is not in the record and was not considered by the District Court in reaching the decree now before us on appeal. It was brought to our attention during the argument by counsel, who said that in the process developed by the defendant after the trial, and now practiced, the Pachuca tanks are eliminated, the pulp being delivered directly from the bucket elevators to the Callow cells. While we are loath to omit from our consideration and judgment anything affecting this very important patent and the art to which it relates, we feel, nevertheless, that we cannot consider and adjudge with propriety or authority a process with respect to which the plaintiff has had no opportunity to produce testimony and which was not embraced in the decree we are reviewing.
We find no error in the decree of the District Court holding valid and infringed claims 1 and 12 of the first patent in suit.
Second Patent.
[3] The second patent involved in this suit, No. 962,678, — also for improvements in ore concentration, — was applied for on April 30, 1909, was issued on June 28, 1910, to Sulman, Greenway and Higgins, and has not been judicially passed upon except by the court below. *771Its particular object is “to separate certain constituents of an ore such as metallic sulfids from other constituents such as gangue when the ore is suspended in a liquid such as water.”
It is also an air-froth flotation process but differs from the first patent, although both processes may be, and both actually are, employed', conjointly. Its essential feature is the use of a mineral-frothing agent in solution, and the method will be best understood by turning to the' specification:
“According to this invention the crushed ore is mixed with water contain, ing in solution a small percentage of a mineral-frothing agent (that is of om or more organic substances which enable metallic sulfids to float under conditions hereafter specified) and containing also a small percentage of a suitable acid such as sulfuric acid, and the mixture is thoroughly agitated; si gas is liberated in, generated in, or effectively introduced into (ho mixture and the ore particles come in contact with the gas and the result is that metallic sulfitl particles float to the surface in the form of a froth or scum, and can thereafter be separated by any well known moans. Among the organic substances which in solution we have found suitable for use as mineral-frothing agents with certain ores are amyl acetate and other esters; phenol and its homologues; benzoic, valerianic and lactic acids; acetones and other ketones such as camphor. In some cases a mixture of two such mineral-frothing agents gives a better result than a single agent. The above mentioned mineral-frothing agents are all more or less effective in the presence of an acid such as sulfuric acid and are given as types but are not intended to form an exhaustive list of suitable organic substances which may be used in this maimer and for these objects. On the other hand there are many organic compounds which in solution will not effect the result described, such as some sugars, dextrin, saponin, albumen, ox gall, etc., and a simple test is required in the case of varying ores or materials to determine which organic compound is most suitable.
“The following is an example of one method of carrying this invention into effect: Water containing a small percentage of sulfuric acid in solution, say from .2 per cent, to 0.5 per cent., and containing in solution a small quantity say 0.1 per cent, of one of the foregoing organic substances (say amyl acetate) is, with finely pulverized ore, introduced into an agitating apparatus, in the proportion of say 3 parts by weight of water to 1 part by weight of ore. The agitation is carried out in such a way as thoroughly to disseminate air through the mixture which is thereafter discharged into a spitz-kasten. It is found that a coherent froth or scum floats on the surface of the water in the spitzkasten. This froth contains a large proportion of the metallic sulfids but is substantially free from gangue. Any well known means may be employed for collecting the froth. If desired the tailings can be re-troated by the same process with or without the addition of fresh quantities of the organic materials referred to. The action may in some instances be improved by heating the mixture. * * *
“Several agitation vessels are placed in series. These may conveniently bo large vats separated by partitions having openings at the bottom so that the liquid may pass from one to another. Each vessel is provided with a rotatable stirrer which is conveniently of the form shown in the drawing. Each stirrer is carried on a spindle rotated at a high speed by any convenient means. Oruslied ore or similar finely divided mineral is fed into the first vessel through any convenient ore-feeding device, * * * and water is also fed into the vessel. A small proportion of acid, such as sulfuric acid, may bo introduced into the water from the feeding vessel, and a small proportion of one or more other soluble substances which enable metallic sulfids to be floated by air under the conditions hereafter specified, may be introduced from the feeding vessel. The liquid containing ore in suspension is vigorously agitated in the agitation-vessels and escapes at the outlet highly charged with air.
*772“A settling apparatus consisting of one or more spitzkasten is placed immediately at tlie outlet from the agitation apparatus. As shown in the drawing, the spitzkasten has a launder to receive the floating froth which passes away through the outlet. The liquid and the sunken material pass out through the outlet at the bottom of the spitzkasten. The level of the liquid in the spitzkasten is slightly above the lip. Within the spitzkasten is lflaced an inclined baffle or guide-plate, which may be made adjustable, extending upward from below the inlet and arranged to direct the stream of ore-particles and air-bubbles toward the surface of the liquid in the spitz-kasten.
“Hitherto many proposals have been made for the wet concentration of ores involving the addition to the liquid in which the ore is suspended of an immiscible liquid. For example in the patent granted to Cattermole, Sulruan & Picard, United States No. 777,274, dated December 13, 1904, is described a process of ore concentration in which metalliferous particles were coated with a thin film of a fatty or rosin acid or a phenol or a cresol by introducing the alkaline compounds of these materials into an acid liquid whereby these materials were liberated in an immiscible or insoluble condition and adhered to the mineral particles. In another known process the powdered ore suspended in water, preferably acidified, is mechanically brought to the surface whereby the particles are exposed to the air and it is found that the metalliferous particles float on the surface while the gangue sinks. In this known process the selective flotation of the metalliferous particles is not due to the metalliferous particles being coated with a selective agent, that is to say, the selective flotatioii is due to the properties of the metalliferous particles themselves when exposed to air or other gas and brought onto the edge or surface of water preferably acidified.
“The present process differs from the two before mentioned types and from other known concentration processes by the introduction into the acidified ore pulp of a small quantity of a mineral-frothing agent; i. e., an organic compound in solution of the kind above referred to and by the fact that the metalliferous particles are brought to the surface in the form! of a froth or scum not by mechanical means but by the attachment of air or other gas bubbles thereto.
“In the frothing processes hitherto known the substances used to secure the formation of a mineral-bearing froth has been oil or an oily liquid immiscible with water. According to this invention the mineral-frothing agent consists of an organic compound contained in solution in the acidified water.
“We do not confine ourselves to the proportions above given, the best proportion can in each case be easily determined by trial.
“It is well known that certain of the organic substances we have referred to are not soluble in water in all proportions and that if used in excess might partly remain insoluble in the acidified water and might become mechanically affixed to the metalliferous pai'ticles of the ore. We disclaim any such use of these substances and only claim them! in such amount as will enable them to dissolve in the acidified water.”
The claims in issue are the following:
“1. The herein described process of concentrating ores which consists in mixing the powdered ore with water containing in solution a small quantity of a mineral-frothing agent, agitating the mixture to form a froth and separating the froth.
“2. The herein described process of concentrating ores which consists in mixing the powdered ore with water containing in solution a small quantity of an organic mineral-frothing agent, agitating the mixture to form a froth and separating the froth.”
“5. The herein described process of concentrating ores which consists) in mixing the powdered ore with water containing in solution a small quantity of a mineral-frothing agent, agitating the mixture and beating air into it in a finely divided state so as to form' froth-and separating the froth.
*773“6. The herein described process of concentrating ores which consists in mixing the powdered ore with water containing, in solution a small quantity oí an organic mineral-frothing agent, agitating the mixture and heating air into it in a finely divided state so as to form a froth and separating the froth.”
The difference between the two patents may be shortly stated to be this: The first process rests upon the use in very small quantity of an oily substance that does not dissolve in water, coupled with agitation of the pulp, and this succeeds in producing a special froth that is remarkably effective in recovering the minute particles of ore. The second process does not employ oil, or an undissolvable substance; on the contrary, the “mineral-frothing agent" must be in solution, and ex vi termini must therefore be dissolvable. The specification disclaims the use of so large a quantity that part of it remains undissolved. The “mineral-frothing agent” is further limited by describing it as “one o.r more organic substances which enable metallic sulfids to float under conditions hereinafter specified”; and, as this general statement does not convey specific information, the patentees give several examples of organic substances that are found to be suitable for use in solution. In passing we may note that claims 1 and 5 are broad enough to cover inorganic frothing agents also, but as no such agent 'is yet known this feature need not now be considered. Just how or why this solution with the needful agitation produces the froth, is not certainly known; but the fact is, that (to use the language of the brief):
“ * * * j^s effect pS] to produce a similar action of air bubbles in the attraction of metallic particles, a similar levitation of the metallic particles, a similar persistence of the bubbles, a similar reliable adherence of the air bubbles to the metallic particles, and a similar capacity for final separation of the metallic particles by their overflow, still in attachment to air bubbles, at the top of a vessel containing the pulp.”
An observable difference in effect is that the froth of the second patent is composed of bubbles much smaller than the bubbles of the. oil process.
We may also note that while the addition of an acid to the mineral-frothing agent is described, as part of the process, this was at that time a. usual practice, and in any event is not an element in the claims now in issue. The agitation is to he thorough, hut in the same connection the means for bringing this about is described in terms that are wide and inclusive. The air or other gas is to be “liberated in, generated in, or effectively introduced into, the mixture,” in order that the ore particles may come into contact with the gas and as a result may float to the,surface in the form of a froth or scum which can be separated afterward by any well known means. The object of introducing the air or other gas into the mixture is such agitation of the pulp as will produce the desired froth, hut the claims are not confined to a particular device or a particular degree of agitation. But of course, the agitation must be thorough and it must be effective, these being matters for experiment but always with the ultimate object of bringing the sulphid particles to the surface and holding them there in the grasp of a froth.
We do not find it necessary to discuss the question of validity; our *774conclusion is, that the patent discloses invention and has not been anticipated. As in the case of the oil process, the patentees seem to have taken “the final step which converted experiment into solution, turned failure into success.” Minerals Separation Co. v. Hyde, 242 U. S. 261, 37 Sup. Ct. 82, 61 L. Ed. 286. And we find nothing in the prior art that can be held to anticipate. The real question upon this patent also is the question of infringement, and here as well as there the decision turns upon the kind and degree of agitation employed by the defendant. We need not dwell upon the subject, for as the defendant used both processes conjointly it is evident that what has been said about the infringing agitation in the oil process must also apply to the same agitation when considered in reference to the second process. There is this difference, however; as pointed out above, the agitation of the second process is so described as to cover expressly a wider range of means and degree than is expressly covered by the first process, and therefore needs less aid, if any, from the doctrine of equivalents. For the reasons given in discussing the oil patent, we think the defendant’s practices there described infringe also the process now under consideration.
Third Patent.
[4] The third patent involved in this suit, No. 1,099,699, — also for improvements in ore concentration, — was applied for on June 30, 1911, was issued on. June 9, 1914, to Henry Howard Greenway, and has not been judicially passed upon except by the court below. As stated in the specification, its process is “a modification of the invention described in U. S'. Patent to H. E. Sulman, A. H. Higgins and myself, No. 962,678, granted June 28, 1910,” which is the second patent here in suit. Greenway’s particular object was “to separate certain constituents of the ore such as copper sulfides (for example in the form of copper pyrites or metallic copper natural or reduced) from.other constituents, such as gangue where the ore is suspended in a liquid such as water.” After describing the process of No. 962,678, as one “applicable generally to the. recovery of metallic sulfides and like floatable metalliferous matter and in case of lead and zinc sulfides to which the process has been largely applied” and stating that in such process “it is necessary for efficient working that the pulp should be lightly acidified, and in most cases-in practice the pulp is heated,” the patentee disclosed his discovery, namely, that both acids and heat can be dispensed with, saying that “it is now found that with copper ore such as "an ore containing copper pyrites effective separation is obtained in the cold without the use of acid by employing as mineral frothing agents, aromátic hydroxy compounds such as phenol, cresol, or mixtures containing the same.” Upon this disclosure the claims here in issue were granted', illustrative of which claim 12 is for “a process of concentrating ores which consists in mixing a powdered ore containing copper with neutral water containing in solution a minute quantity of cresol, agitating the mixture in the cold to form a froth and separating the froth.” In the court below the patent was held invalid and agreeing as we do with *775the conclusion reached by it. in reference to the first and second patents, we are the more inclined to follow its decree in reference to the, third patent. But an examination of the proofs satisfies us that the process disclosed in this patent was a substantial departure from processes of the prior art. The heating of water is a matter of large moment in large operations, and the use of acid is a matter of constant and considerable expense. By wholly dispensing with both by the use of a minute quantity of hydroxy compounds, the patentee has disclosed an original and novel plan which has broadened and made more simple the agitation process of air flotation. The length of this opinion, rendered necessary in the full discussion of the first patent, is the sufficient warrant for our refraining from a detail discussion of the proofs and reasons which lead to our conclusion as to the novelty and inventive character of Greenway’s discovery, and we therefore limit ourselves to stating that after full consideration we have reached the conclusion that his patent is valid, and, for the reasons stated in discussing the first patent, is infringed by the defendant.
It is ordered that the part of the decree of the District Court holding valid and infringed claims 1 and 12, and invalid claim 9,'of Letters Patent No. 835,120, and holding valid and infringed claims 1, 2, 5 and 6 of Letters Patent No. 962,678, be affirmed, and that the part holding invalid claims 1 to 12 of Letters Patent No. 1,099,699, be reversed, and that a decree in accordance with this opinion be entered.

 British Ore Concentration Syndicate, Ltd., v. Minerals Separation, Ltd., 25 R. P. C. 741, High Court of Justice, Chancery Division, affirmed after intermediate reversal in the Court of Appeals by the House of Lords in Minerals Separation, Ltd., v. British Ore Concentration Syndicate, Ltd., 27 R. P. C. 33; Ore Concentration Company, Ltd., v. Sulphide Corporation, Ltd., Supreme Court New South Wales, 31 R. P. C. 216, 217; Ore Concentration Company, Ltd., v. Sulphide Corporation, Ltd., 31 R. P. C. 206, Privy Council British Empire; Minerals Separation, Ltd., v. Hyde, 207 Fed. 956 (D. C. Montana); Hyde v. Minerals Separation, Ltd., 214 Fed. 100, 130 C. C. A. 576 (C. C. A. 9th Circuit); Minerals Separation, Ltd., v. Hyde, 242 U. S. 261, 37 Sup. Ct. 82, 61 L. Ed. 286; Minerals Separation, Ltd., v. Miami Copper Co., 237 Fed. 609 (D. C. Delaware).