Full opinion text
CAMPBELL, District Judge. This is a suit for patent infringement; Texas charges that Globe, at or near Lemont, Illinois, and elsewhere, has, infringed U. S. Patent No. 1,883,850, applied for November 21, 1918, and issued on October 18, 1932, to Texas as assignee of the applicant Otto Behimer. (The original' application had been by Plolmes, Manley and Behimer; prior to the patent issuance, Behimer had become the sole applicant.) The patent in suit is based on a divisional application dated April 6, 1923. It consists of a specification of 3% pages plus a diagrammatical drawing, and of 44 claims extending over 6 printed pages. The 5 claims in suit (12, 22, 36, 39 and 40) relate to a process of oil conversion sometimes called “thermal cracking”, whereby the oil is passed once through a heating coil or heating zone, where it is raised to a cracking temperature, thence to a second zone where the vapors are evolved and where the residue is removed without re-circulation; the lighter vapors are drawn off as the desired product; but the heavier vapors are passed into a reflux condenser and thénce returned under maintained mechanical pressure to the charging line leading to.the heating coil and so re-circulated. Globe’s answer alleges (inter alia) that its method of making gasoline is wholly different in fundamental principles of operation and in result, from the process disclosed and claimed by the patent in s.uit; that the patent, if construed to be infringed by any practice of defendant, is invalid because it does not contain any patentable novelty in view of the prior art; that Behimer was not the original inventor of the alleged invention; that the claims of the patent do not cover valid and patentable combinations ; that long prior to the making of the alleged invention and more than 2 years prior to the application date, the alleged invention, or substantial, and material parts thereof, were described, shown and patented in certain patents (naming them) ; that the alleged invention of the patent in suit and every substantial and material part thereof were, prior to Behimer’s date of invention, known and invented and reduced to practice by one Ellis and one Alexander, who respectively filed patent applications on which U. S. patents issued; that plaintiff has stood inactive for many years with full knowledge of defendant’s operation, and has been guilty of Laches; that during the course of the prosecution of the application for the patent in suit and during an interference with one Dubbs, plaintiff disclaimed and abandoned the subject matter of the interferences and failed to amend the claims so as to patentably distinguish them from the subject matter thus disclaimed and abandoned; that this disclaimer was executed pursuant to settlement agreement between Texas and Universal Oil Products Company, whereby the alleged invention was apportioned between them and the monopoly of the previously issued Dubbs patent extended beyond the statutory period; that the patent in suit is invalid because neither plaintiff nor Behimer, at the time of the filing of the original application, knew of any commercial means for return of hot reflux to the heating coil inlet. The patent in suit, the 5 claims in suit (and some others.) and many of the issues here involved, have been heretofore litigated in Texas Co. v. Anderson-Prichard Refining Corporation, 10 Cir., 1941, 122 F.2d 829, affirming the decree of the District Court holding the patent valid but not infringed, 32 F.Supp. 347. Defendant submits this decision as persuasive; plaintiff denies that the decision is persuasive and says that the record here is substantially different. Trial was before a master; from his report and the accompanying record, it appears that on each side the case has been exhaustively prepared and presented. The hearings occupied 71 court days; the transcript consisted of over 10,000 typewritten pages; numerous exhibits, were offered by each side. The oral argument occupied 11 court days; the transcript thereof consists of over 1700 pages. The respective parties submitted to the master numerous printed Findings of Fact and Conclusions of Law, and printed Briefs aggregating over 1400 printed pages. (The master originally issued a draft report and served notice that counsel might file objections thereto; both parties filed objections and subsequently argued these objections; the master then issued his definitive report, being the document now under consideration.) The report is a lengthy document, consisting of 436 printed pages; it makes detailed Findings of Fact — 294 in number and states detailed Conclusions of Law — 129 in number. The master found against defendant on all its defenses except the construction of the claims; he concluded that the claims, properly construed, did not cover defendant’s operation and recommended that the suit be dismissed. The matter comes up before me on this report and on the objections thereto filed by plaintiff (69 in number and taking S3 printed pages) and by defendant (148 in number and taking 27 printed pages). The respective counsel have also filed several supporting printed briefs. The process of the claims in suit, and the defendant’s operation, have the same general objective, i. e., to crack or decompose the heavier hydrocarbons into lighter constituents, specifically gasoline. Some forms of cracking ante-dated Bebimer. Before his invention, it was well known in the art that cracking could he brought about by subjection of the heavier materials to a proper temperature for a sufficient time; commercial cracking processes to make gasoline had been successfully carried out by heating and cracking in directly fired zones or containers, sometimes drums or tanks, sometimes tubes or coils. As of November, 1918, the date of Behimer’s original application, there were in commercial operation, two schools of cracking. The one was. the “liquid phase” method where a body of liquid oil was cracked and distilled, generally in a receptacle (usually a tank or drum) maintained under superatmospheric pressure so as to increase the boiling point to such a temperature that the oil would crack while still in liquid form; the other was the “vapor phase” method, where the oil was heated and vaporized either completely or to a substantial degree, and then cracked. The liquid phase method operated at low temperature and with a long time factor, the vapor phase method, at high temperature and with a short time factor; the liquid phase product was a white, sweet natural gasoline low in unsaturates, the vapor phase product was unlike natural gasoline in that it was of bad color, had. a foul odor and was rich in unsaturates. Originally the liquid phase product was much preferred commercially. However, with the further development in the 1920’s of the high compression automobile engine, it became desirable to procure gasoline of high octane content, the so-called “anti-knock” gasoline, and it was found that the vapor phase product had thes.e high-octane properties and was, therefore, more suited from this standpoint for the high compression engines than the previous liquid phase product, or the natural gasoline. The result has been that the natural gasoline and the liquid phase cracked product both yielded in desirability to the vapor phase cracked product. In ante-Behimer processes, the principál difficulty was that the subjection of the hydrocarbon stocks to the heat necessary to crack them, produced not only the desired lighter product, but also carbon and heavy carbonaceous materials. This carbon tended to deposit on the highly heated surfaces of the metal “firing zone;” the metal became insulated, was apt to overheat and decrease in strength; the “firing zone” whether drum, tank, coil or tube, was prone to bulge, crack or burst. This was the “carbon problem” that was then so important and so difficult in the practice of the cracking art. Behimer’s invention (as his specification explicitly states) was concerned with this carbon problem and had a solution for it. Instead of heating and cracking in the same zone, Behimer’s idea was to have two zones, one a heating zone in which the charging stock would be heated under super-atmospheric pressure to a temperature just under cracking, and a second zone, unheated or lightly heated, into which the liquid would be deposited from the first zone — and in which second zone, the liquid would be allowed to remain for a comparatively long period and in which the actual cracking would take place. This second, or cracking zone had two outlets; one from which the the carbon residue was drawn away; the other from which part'of the cracked liquid passed out to constitute the desired product. In this way, there was only a small or incipient cracking in the "heating zone” and consequently, no harmful deposit of carbon there; the carbon deposit was all in the second or cracking zone, where it could be drawn away with no harmful consequences. Claim 12 in suit is typical and reads as follows : “12. -A process of oil conversion that comprises passing the oil onte through a heating coil where it is raised to a cracking temperature and into a drum where a substantially constant body of liquid oil is maintained and vapors evolved, separating the heavier constituents of the evolved vapors and returning them while still hot and without substantial drop in pressure under mechanical pressure to the heating coil for retreatment, removing residuum from the drum while preventing recirculation of residuum through the coil, maintaining super-atmospheric pressure through the coil and drum and continuously supplying charging stock.to the process.” Plaintiff contends that an essential feature of the patent in suit and of the claims in suit is “dean circulation”, which plaintiff defines as a continuous coil and drum pressure cracking operation, whereby cracked residual oils are withdrawn from the drum and discharged from the system; the separated vapors pass from the drum into a dephlegmator, in which vapors heavier than gasoline are condensed "as reflux and the reflux from the dephlegmator is directly returned while hot to the heating coil and is forced under mechanical pressure through the coil with the fresh oil supplied thereto. This feature is set out in specification, where, after describing “the process of coil heating, drum cracking, and permanent withdrawal of residue,” and after stating that the process “in its broad conception” is then complete (p. 1, 11. 81 — 82) Behimer describes an additional preferable step as follows (p. 1, 11. 82 et seq.) : “ * * * the light products preferably continue the cycle, leaving the cracking zone in the form of vapor and gas. These vapors and gases are then subjected to a reduction in temperature, whereby the heavier constituents thereof, such as kerosene, are condensed. The condensate preferably is combined with the charging oil entering the heating zone, thus completing the cycle.” (Emphasis supplied) There were issued out of the Behimer Patent Application, a total of four patents, namely: (a) No. 1,585,496, issued May 18, 1926, Reissue No. 16877 issued February 14, 1928 (on a divisional application), sometimes referred to as “starting-up” patent. (5 claims) (b) No. 1,840,012, issued January 5, 1932, on, a divisional application, sometimes referred to as the “apparatus” patent. (2 claims) (c) No. 1,883,850, issued October 18, 1932, on a- divisional application (the patent in suit) (44 claims), (d) No. 2,027,014, issued January 7, 1936, on the parent application, sometimes referred to as “postponed cracking” patent. (23 claims). Defendant’s operation is under what is known as the Winkler-Koch process. This process was developed in the late 1920’s by Lewis E. Winkler and Fred G. Koch, experienced petroleum engineers; it is not patented. In 1930, the Winkler-Koch process was first put into operation in defendant’s plant at Lemont, Illinois. The record contains written stipulations by the parties as to the nature of defendant’s operation, which appears to be as follows: There are 2 cracking furnaces, No. 1 and No. 2. In each furnace is located a coil consisting of 5 banks of tubes, each tube approximately 27 feet long, 3 inches (Inner Diameter) ; each coil is approximately one mile long and the oil completes, its passage through the coil in about 5 minutes. The charge enters the furnace coil at sub-cracking temperature of 610° in each furnace with a pressure in furnace No. 1 of 555 lbs. and in furnace No. 2 of 763 lbs. In the coils, the oil is raised to a maximum outlet temperature of 935° in furnace No. 1; 925° in furnace No. 2; under an outlet pressure in each furnace of 350 lbs. In the passage of the oil through the coils, substantial and principal cracking takes place; vapors are formed in the coils travelling along with the liquid as a foamy mass and are subjected to the same conditions of time and temperature as the liquid. The two streams (each part oil and vapor) after leaving their respective cracking furnaces, are joined together and the united stream passes through a pressure release valve where the pressure isi reduced from 350 lbs. to about 42 lbs. Beyond this valve the hot stream is met by a, cooler (relatively) stream of topped crude oil from the pre-heater furnace (outlet temperature 765°, pressure 89 lbs.) and the combined streams enter a vapor separator consisting of a vertical still 8feet in diameter and 34 feet high. The reduction in pressure of the streams from the cracking furnace, plus the quenching of these streams by the cooler topped crude, results in a reduction of temperature of the oil in the bottom of the vapor separator to 815°. No liquid level is maintained in the vapor separator. From the bottom of the vapor separator, the heavy liquid residue is led off to a small vertical drain drum through a pipe having a control device located 2 feet above the bottom of .the drain drum. In the drain drum, there is maintained only’ enough heavy liquid residue (amounting to approximately 2 barrels) necessary to provide a liquid seal to prevent the escape of vapors down the residue withdrawal line; the balance of the heavy liquid residue is withdrawn and not returned to the system. The vapors further pass (through a heat exchanger) to a bubble tower, 12 ft. in diameter, 66 ft. high, where they are subjected to partial condensation and are cooled to a temperature of 315° at the top of the tower. The vapor constituents heavier than gasoline are condensed and separated from the lighter vapors which contain gasoline; these lighter vapors constitute the final product of the process and then pass on to final condensation as gasoline. The liquid in the bottom of the bubble tower is a mixture of the insufficiently cracked material or reflux from the cracking coils, and of the charging stock made by distillation of the topped crude. This material is continuously withdrawn from the bottom of the bubble tower and is pumped as charging stock to the two cracking coils. Intermediate products are withdrawn by side streams from the bubble tower; from the higher side stream at 426°, cracked naphtha and from the lower side stream at 477°, cracked distillate. In defendant’s operation the oil is cracked in the coils, about 15% by volume of the stream being converted to gasoline of 355° end point. At the outlet of the coils, the oil has been vaporized to about 90% by weight, and about 96% by volume of the tube space, and the stream has acquired a velocity of about 40 ft. per second. As vapors form in the coil, they travel along with the liquid as a foaming mass, and are subjected to the same cracking conditions of time and temperature as the liquid. As cracking proceeds, lighter products, including gasoline, and also heavier products are formed, and are mingled in the cracking coil with the combined stream of clean reflux and fresh feed. About 1% of the total gasoline made in the system is made in the vapor separator. Of the gasoline formed by cracking in the coil of No. 1 cracking furnace, 60% was produced by liquid phase cracking; of the gasoline formed by cracking in the coil of No. 2 cracking furnace, 67% was produced by liquid phase cracking. Defendant in its process and operation, meets the carbon problem by avoiding the deposit of carbon in substantial quantities anywhere in its system. It does this by: charging only a clean stock to the cracking coils, such clean stock consisting of clean fresh feed and clean reflux; using cracking furnaces of modern design; regulating the process with automatic control instruments ; using high temperatures and short time factors in the cracking coils; regulating the crack per pass therein to a point short of that where carbon in harmful amounts would be deposited; stopping the cracking operation in the vapor separator save for the unavoidable incipient cracking resulting from the distillation of the topped crude; using a high velocity in the cracking coils; withdrawing and not returning to the system the carbon laden residue resulting from the cracking operation. Defendant’s operation solves the carbon problem by cracking in the coil at a high temperature with a short time factor and then depositing the oil, after quenching and a pressure reduction, in the vapor separator (this vapor separator corresponding to the Behimer drum); defendant’s operation includes a continuous charge; and it also includes “clean circulation,” that is permanent removal'of residue from the vapor separator (drum) and direct pump return of the hot reflux to the charging line. There is a verbal correspondence between the language of at least some of the claims in suit and that of defendant’s operation; for example, between the different elements of claim 12 and defendant’s process in that each of the elements of the claim is found in defendant, namely: 1. passing the -oil once through a heating coil where it is raised to a cracking temperature, 2. and into a drum where a substantially constant body of liquid oil is maintained and vapors evolved, 3. separating the heavier constituents of the evolved vapors, 4. and returning them while still hot and without substantial drop in pressure under mechanical pressure to the heating coil for retreatment, 5. removing residuum from the drum while preventing recirculation of residuum through the coil, 6. maintaining super-atmospheric pressure through the coil drum, 7. and continuously supplying charging stock to the process. Plaintiff’s contention, reduced to its simplest form, is that defendant’s process infringes Behimer because Behimer is broad enough to include not only heating in the coil (the firing zone) and cracking in the drum (the second zone), but also cracking in the coil. Defendant’s position is that Behimer properly construed, discloses only incipient cracking in the coil and requires that substantially all the cracking take place in the drum; moreover, defendant alleges that if Behimer patent were susceptible of plaintiff’s broad construction, it would be invalid on the prior art. Plaintiff’s further contention— again reduced to its simplest form — is that the Behimer patent includes an independent invention of “clean circulation; ” i. e., withdrawal of the residue from the cycle and forcible return of the hot reflux condensate to the coil inlet. Defendant denies that Behimer had any independent invention of clean circulation; further, that Behimer by his disclaimer in the Patent Office had abandoned “clean circulation” generally and had retained only “clean circulation with a pump” and that this limited claim could not be the subject of a valid patent since a pump was not a patentable element. This disclaimer issue occupies a substantial part of the record. As already noted, the original Behimer application had been filed on November 21, 1918, although the patent in suit did not issue thereon until October 18, 1932, almost 14 years thereafter. On March 19, 1919, one C. P. Dubbs filed an application on which patent No. 1,392,629 issued October 4, 1921 while the Behimer application was still pending. On December 26, 1922, Behimer presented claim 42 in his application: the Patent Office held that it -covered subject matter substantially identical with that covered by certain claims of the issued Dubbs' patent, except that Behimer did not have Dubbs’ first step limitation against permitting “substantial vaporization of the oil in bringing it to a cracking temperature,” which difference the Patent Office held to be immaterial. At the request of the examiner, Behimer copied certain claims of the Dubbs patent, and on June 8, 1923, interference No. 49,355 was declared between Behimer and Dubbs; all the counts called for residue withdrawal, and return of reflux, without specifying any particular method of reflux return. On December 12, 1918, Du’bbs had filed another application No. 266,396 containing claims which were indistinguishable from those of his (later issued) patent No. 1,392,629 except (1) that they were not limited to “without substantial vaporization” in the coil (as were the claims in the ’629 patent) and (2) that they included the return of the reflux with a pump (the ’629 patent did not specify any means of returning reflux). The Patent Office rejected this second Dubbs application as double patenting; Dubbs appealed and procured a reversal holding that the addition of the element of mechanical pressure for returning the reflux, differentiated this application from the prior Dubbs and that the new process (embracing the mechanical pressure step) was patentable. The Dubbs pump claims were therefore incorporated in a Divisional Dubbs application and because of their identity in subject matter with certain claims of the pending Behimer application, a second Behimer-Dubbs interference No. 55,610 was declared on July 15, 1927. The counts did not contain any limitation to operations “without substantial vaporization” in the heating coil; the issue was priority of invention of the con-' cept of clean circulation with forced mechanical return of reflux. Both Interferences lay dormant for many years. In December, 1931 (pursuant to an agreement between Universal Oil Products, as assignee of Dubbs, and Texas, as assignee of Behimer) Behimer entered a disclaimer, in the -clean circulation Interference No. 49,355 and Dubbs entered a -disclaimer in the pump Interference No. 55,610. Thereafter, in Behimer’s Divisional application, all claims not already limited to a pump were rejected on the issue of clean circulation Interference No. 49,355 and on the alleged prior art patent to Trumble No. 1,281,884. Behimer did not appeal from the rejection, but acquiesced therein and on July 8, 1932, he amended and rewrote the claims to include specifically the element of reflux return “under mechanical pressure.” Upon termination of Interference No. 55,610 by Dubbs’ disclaimer, all the claims of the Behimer application, including return of reflux under mechanical pressure, were allowed. Before taking up the main issues of the case, there is a special -defense that requires mention. Defendant charges plaintiff with laches. On this issue, it appears that the Behimer patent issued October 18, 1932, and that the instant suit was brought January 10, 1942. (The actual trial, by agreement of counsel, was postponed until after the end of World War II and did not commence until April, 1947). Defendant argues that the 9 year delay from October, 1932 to January, 1942, shows laches. The record disclosed that during this 9 year -period, plaintiff had not stood idle but had vigorously asserted the validity of the Behimer patent, and plaintiff’s intention to sue infringers; that plaintiff had actually started many infringement suits on this patent in the several courts throughout the country against other members of the Winkler-Koch group. This group was so called because they all purchased and operated the Winkler-Koch cracking still and contributed to a fund to be used in the defense of patent suits brought against any user; defendant was a member of this group and made substantial contributions thereto. Many of these defendants later settled by taking licenses from plaintiff; defendant here negotiated for years with plaintiff for a license but no agreement was reached. Defendant introduced evidence of substantial expenditures made by it in expanding its plant at Lemont, Illinois, some of these expenditures before the filing of the present suit, some thereafter. . I agree with the master’s holding that defendant was never lulled into any sense of security, that de-> fendant from the time of the issuance of thé Behimer patent knew that plaintiff claimed defendant was infringing. There was no equitable estoppel here as in Dickerson v. Colgrove, 100 U.S. 578, 580, 25 L.Ed. 618, or Lukens Steel Co. v. American Locomotive Co. 2 Cir., 1939, 197 F.2d 939. Brennan v. Hawley Products Co. 7 Cir., 182 F.2d 945 cited by defendant, deals with such a different factual situation that it does not apply. The defense of laches is not sustained. I come now to the principal issue of the case — the proper construction of the plaintiff’s patent. The claims in suit here provide for a coil and drum cracking process with clean circulation including reflux return by pump. There is in none of these claims, any express designation of a locus of cracking. If the claims are to be read by themselves — without reference to the disclosure of the specification — they do not specify any locus and might be broad enough to embrace either cracking in the coil, cracking in the drum, or cracking in both. Plaintiff contends that the claims must be given this broad construction and that, so construed, defendant infringes. It is elementary that the specification and claims of a patent constitute a contract between the United States and the patentee and they should be read and construed together, not for the purpose of limiting, contracting or expanding the claims, but for the purpose of ascertaining from the entire agreement the actual intent of the parties. The scope of every patent is limited to the invention described in the claims read in the light of the specification. Claims must be construed in the light of the specification and may never transcend the actual invention. Snow v. Lake Shore R. Co., 1887, 121 U.S. 617, 7 S.Ct. 1343, 30 L.Ed. 1004; Westinghouse v. Boyden Power Brake Co. 1898, 170 U.S. 537, 18 S. Ct. 707, 42 L.Ed. 1136; State Bank of Chicago v. Hillman’s, 7.Cir., 1910, 180 F. 732; Kennicott Co. v. Holt Ice & Cold Storage Co. 7 Cir, 1915, 230 F. 157; Burroughs Adding Machine Co. v. Felt & Tarrant Mfg. Co. 7 Cir., 1917, 243 F. 861; Benoit v. Wadley Co. 7 Cir., 1932, 54 F.2d 1041; Corn Products Refining Co. v. Penick & Ford Ltd, Inc, 7 Cir., 1932, 63 F.2d 26; Weil Pump Co. v. Chicago Pump Co., 7 Cir., 1934, 74 F.2d 13; Charles Peckat Manufacturing Company v. Jacobs, 7 Cir., 1949, 178 F.2d 794. Plaintiff’s position is that the claims should be read in the light of the specification where necessary in order to make them intelligible, but that this does not justify reading the claims as covering only the “specific embodiment” given in the specification; that the disclosure in Behimer’s specification of a coil heating, drum cracking operation was only a “specific embodiment” of the general cracking operation set out in the claims. Defendant’s answer is that the disclosure in the Behimer specification is not a “specific embodiment” of a general invention but it is the general invention itself, namely,, the separation of the heating .from the cracking zone. Defendant stresses Snow v. Lake Shore etc. Railway, 121 U.S. 617, 7 S.Ct. 1343, 30 L.Ed. 1004, where there was a specific embodiment, i. e., a steam driven bell ringer for locomotives and also a disclosure that the detachment of the piston from the piston rod was the gist of the invention; in the defendant’s structure, the two were not detached: plaintiff argued that the detachment was merely preferable, not essential, and that the claim should not be limited to the structure of the specification; that the first claim did not call for the detachment of the rod and piston and that claim therefore read on defendant’s connected structure. Nevertheless, the Supreme Court read the detachment into the claim because it was the gist of the invention.and thus limited, the claim was held to be not infringed; the court said, 121 U.S. at page 630, 7 S.Ct. at page 1351: “And when we compare the device as described in the specifications of the patent sued on with that of the patent of 1854, in which it was necessary to use stuffing-boxes, and consider that one of the express objects expected to be accomplished by the improvement contained in the patent of 1872 was to prevent leakage of water or steam without resort to stuffing-boxes, the conclusion seems unavoidable that the patentee intended the detachment of the piston from its rod as an essential part of the combination to be covered by the first claim.” Plaintiff cites Tilghman v. Proctor, 1880, 102 U.S. 707, 26 L.Ed. 279; Continental Paper Bag Co. v. Eastern Paper Bag Co., 1908, 210 U.S. 405, 28 S.Ct. 748, 52 L.Ed. 1122; Smith v. Snow, 1935, 294 U.S. 1, 55 S.Ct. 279, 79 L.Ed. 721; Permo, Inc., v. Hudson Ross, Inc., 7 Cir., 1950, 179 F.2d 386; Lewyt Corp. v. Health-Mor, Inc., 7 Cir., 181 F.2d 855; Graver Tank Mfg. Co., Inc., v. Linde Air Products Co., 339 U.S. 605, 70 S.Ct. 854, 94 L.Ed. 1097. These cases, in my opinion, are distinguishable from the case at bar. In Tilghman v. Proctor, 102 U.S. 707, 26 L. Ed. 279, Tilghman was the inventor of the basic chemical processes of making fatty acids and glycerin from fatty bodies by effecting the decomposition of fats under the action of heat and pressure in the presence of water; he also disclosed in his specification an apparatus for carrying out that process; the defendant used a different apparatus but appropriated the basic chemical process; the Supreme Court held that Tilghman claim should not be restricted to his specific apparatus, but that any apparatus which served to carry out the basic process would be an infringement. The case might be in point were Behimer, like Tilghman, the inven tor of the basic time-and-temperature-induced cracking process; .but that process was old and well-known before Behimer; so also was the very apparatus — coil, drum, dephlegmator and condenser — which Behimer mentioned in his specification, so nothing new remained for him but to specify certain cracking steps — coil heating and drum cracking — in that already known apparatus. In Continental Paper Bag Co. v. Eastern Paper Bag Co., 210 U.S. 405, 28 S.Ct. 748, 52 L.Ed. 122, the court held valid and infringed a patent on a paper bag machine, overruling the contention of defendant that defendant did not infringe because of differences between its machine and the machine specifically described in the specification of the patent. The court pointed out that the invention is not confined to the specific disclosure of the patent; otherwise most patents would be of little worth; also that there must be a description of the invention and the mode of putting it to practical use, but that the claims measure the invention. The court contrasted the situation there with that in Snow v. Lake Shore, etc. Railway Co., 121 U.S. 617, 7 S.Ct. 1343, 30 L.Ed. 1004, where, in the specific embodiment (i. e., a steam driven bell ringer for locomotives) the detachment of the piston from the piston rod was the gist of the invention, and held that there was nothing here to show that the specific embodiment was intended to be the gist of this invention. In Smith v. Snow, 294 U.S. 1, 55 S.Ct. 279, 79 L.Ed. 721, the advance — the “broad conception” — was in the moving air incubator of" the patent over the still air incubator of the prior art; as an auxiliary feature of refinement, the specification also mentioned that the air current should pass first to the eggs of more advanced incubation; in the accused incubator, the initially introduced air did not follow this 'route and the claims were silent on the point; the Supreme Court refused to restrict the claims to this precise detail of the specification because it was not the gist of the invention; the court said, 294 U.S. at page 12, 55 S.Ct. at page 283: “ * * * while the specifications and drawings show a particular arrangement of the eggs and a particular direction of the current,- nowhere, in the specifications or claim, is it stated either that the direction of the current is material or, what is the equivalent, that the order in which it reaches the eggs is material.” Behimer’s patent does not state that whether the oil is cracked in the coil or in the drum is immaterial; on the contrary, he teaches that the sequence of the heating and cracking steps is vital; he calls coil heating and drum cracking his “broad conception” and contrasts its benefits in solving the carbon problem with the substantial carbon formations of the destructive character which have proved such an impediment in prior systems. In Permo, Inc., v. Hudson Ross, Inc., 7 Cir., 1950, 179 F.2d 386, the court held that on the issue of validity, specification limitations could not be implied in a broad claim, thus saving it from prior art references. In Lewyt Corp. v. Health-Mor, Inc., 7 Cir., 1950, 181 F.2d 855, the specification did not say that the embodiment described was what solved the theretofore unsolved problem of the prior art; the immaterial details of construction were held not to be a limitation on the invention. Plaintiff stresses Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U.S. 605, 70 S.Ct. 854, 855, 94 L.Ed. 1097, particularly the statement of Mr. Justice Jackson that if literal infringement appears, "that is the end of it.” It seems to me that this statement, taken in its context, does not have this broad meaning, as is plainly indicated by the reference to Westinghouse v. Boyden Power Brake Co., 170 U.S. 537, 18 S.Ct. 707, 42 L.Ed. 1136, cited in support of the d.octrine that “where a device is so far changed in principle from a patented article that it performs the same or a similar function in a substantially different way, but nevertheless falls within the literal words of the claim, the doctrine of equivalents may be used to restrict the claim and defeat the patentee’s action for infringement.” Moreover, Mr. Justice Jackson further states, 339 U.S. at page 609, 70 S.Ct. at page 856, that equivalency “must be determined against the context of the patent, the prior art, and the particular circumstances of the case.” Thus tested, it seems to me that coil cracking cannot possibly be held to be equivalent of coil heating and drum cracking. In the specification of the patent in suit, Behimer again and =again discloses that the primary purpose of .his invention is to solve the previously existing carbon problem and that he solves this by separating the heating zone from the cracking zone, so that the oil to be cracked, is in the heating zone only a short time and under such circumstances that there will be no substantial cracking therein. The oil leaves the heating zone at the point of incipient cracking; it is deposited in the enlarged cracking zone (unheated or lightly heated) where it remains a comparatively long space of time, so that cracking takes place there, and the carbon formed there is comparatively harmless: p. 1, 11. 17-29: “It is a broad novel feature of the herein disclosed process that substantially all of the cracking operation occurs in a vessel to which no external heat is applied, except at such times .and in such quantities as are necessary to compensate for heat losses, the oil prior to its introduction to such vessel having been subjected to a high degree of cracking heat. * * As a consequence, I avoid substantial carbon formations of the destructive Character which have proved such an impediment to- prior systems.” p. 1, 11. 38-46: “The oil to be treated on entering this circuit is subjected to a high degree of heat, but the time element is so controlled with respect thereto that there is comparatively little decomposition and deposition of carbon while it is exposed to this external heat, the oil being rapidly removed from the heating zone and conducted to the cracking zone * * * ” p. 1, 11. 65-72: “Thus, although the oil is subjected to cracking heats in the heating zone, this temperature is attained only just previous to the exit of the oil therefrom, and therefore, the oil leaves the heating coil before any substantial decomposition and incident deposition of carbon takes place.” p. 1, 11. 72-86: “Subsequently, the highly heated oil in a state of incipient decomposition, is delivered to the cracking zone, where the desired temperature and the pressure conditions are continuously- sustained and the cracking of the oil and the incident decomposition (deposition) of carbon are effected.” p. 2, 11. 32-34: •“ * * * since I conduct substantially all of the cracking in a vessel to which' either no external heat is applied or only a small quantity of heat is applied. * * *” This language- seems to indicate that Behimer -conceived his invention as prohibiting any substantial cracking in the coil and that coil heating and drum cracking was not only a specific embodiment of the general invention, but was the invention itself. Plaintiff, it is true, contends that the specification does disclose a teaching of cracking in the coil because of the temperature range revealed (p. 3, 11. 120, 121): “ * * * with a temperature in the coil 1 of from 700° F. to 950° F. is ordinarily used,” which temperature of 950° would involve some cracking (approximately 4% per pass) in the coil. I agree with the master that the use of this temperature (at the top of the range) would not — in view of the language of the rest of the specification —disclose to “the man skilled in the art” that Behimer taught cracking in the coil. It is my opinion that the claims in suit read according to their wording in the light of the disclosure of the specification, imply a locus of cracking in the drum; that the claims not only do not embrace cracking in the coil but that they forbid it. Plaintiff argues that its construction of the claims in suit (to include cracking either in the coil or drum) is supported by the doctrine of “claim differentiation.” The patent in suit contains 44 claims; in most of these claims, the locus of cracking is specifically designated as the drum; in the 5 claims in suit, no locus of cracking is specifically designated. Plaintiff contends that the omission of any limitation as to locus of cracking from the claims in suit clearly appears as an intentional omission, in view of the incorporation of such a limitation in other claims; that, in construing the claims in suit, effect should be given to the “striking and obviously intended contrast with other claims”. Smith v. Snow, 294 U.S. 1, 14, 55 S.Ct. 279, 284. The essence of the doctrine of “claim differentiation” is that a patentee is entitled both to narrow claims particularly directed to the preferred embodiment, and, to broad claims which define the invention without reference to the details of the- disclosure; that in such case, the presence of the narrow claims negatives the limiting (by implication) of the broader claims; that the presence of an express limitation in one claim negatives an intent similarly to limit by implication a claim in which the limitation is not expressed; that the spelling out of the specific limitation in one or more claims gives special significance to the absence of such a specific limitation in another claim, because under such circumstances the attention of the applicant and the Patent Office is shown to have been directed to the limitation or to its absence, and the intent is clear that when the limitation was intended it was expressed. Plaintiff argues that the patent in suit has r narrow claims (e.g. Claim 43, among others) particularly directed to the preferred embodiment and including an explicit limitation as to locus of cracking, and broad claims (e.g. 12, 22, 36, 39 and 40, the claims in suit) which do not include any limitation as to the locus of cracking; that, therefore, the unequivocal spelling out of a locus of -cracking, both as to where it shall and where it shall not take place (as in Claim 43) gives special significance to the-absence of any locus of cracking in the claims in suit, and shows that the intent of Behimer and the Patent Office was that the claims in suit should contain no limitation as to -locus of cracking. Defendant contends that the doctrine of claim differentiation has a qualification that the accused operation must be properly or fairly comprehended under “the invention” and that the doctrine does not apply to cases, (such as defendant contends to be the case at bar) where the accused operation is not properly or fairly comprehended under the invention, but is “antithetical” to the invention. Plaintiff replies that the end of all construction should be to determine the intent expressed in the claim, and that the absence of an explicit limitation —which is always an indication of intent to omit the limitation — becomes an even stronger expression of intent, if the limitation is expressed in other claims. I have examined the numerous cases cited by counsel. My conclusion therefrom is that the broad claims in suit, with no specific limitations to a locus of cracking — and with other claims in suit specifying a cracking locus in the drum — would be entitled to be construed broadly as including cracking in the coil, if such broad construction were consistent with the invention as disclosed by the specification, but that the claims in suit cannot be so read if such broad construction were inconsistent with the invention disclosed in the specification, and were indeed antithetical to it. Snow v. Lake Shore, etc., Railway Co., 1887, 121 U.S. 617, 7 S.Ct. 1343, 30 L.Ed. 1004; Smith v. Snow, 1935, 294 U. S. 1, 55 S.Ct. 279, 79 L.Ed. 721; Lamson Consolidated Stores Service Co. v. Hillman, 7 Cir., 1902, 123 F. 416; State Bank of Chicago v. Hillman’s, 7 Cir., 1910, 180 F. 732; Kennicott Co. v. Holt Ice & Cold Storage Co., 7 Cir., 1915, 230 F. 157; Burroughs Adding Machine Co. v. Felt & Tarrant Mfg. Co., 7 Cir., 1917, 243 F. 861; Benoit v. Wadley Co., 7 Cir., 1932, 54 F.2d 1041; Weil Pump Co. v. Chicago Pump Co., 7 Cir., 1934, 74 F.2d 13. The application here of this principle seems to me clear; in view of the language in the specification (hereinabove quoted) a broad construction of the claims in suit to include coil cracking — is not only, not disclosed in the invention of the specification, but is there disclosed as something transcending the invention, indeed opposed to it; therefore, in my opinion the doctrine of “claim differentiation” does not sustain plaintiff’s construction. Plaintiff argues that its broad construction of- the claims is supported by the issuance of -the four patents, particularly the “postponed' cracking” patent. From the Behimer Patent Application, Serial No. 263,562 of November 21, 1918, four patents ultimately issued, as above noted; the “starting up patent” 1,585,496, reissue 16,-877; the “apparatus patent” 1,840,012; the patent in suit 1,883,850; and the “postponed cracking patent” 2,027,014. Plaintiff argues that under the Patent Office rule 41, two or more “independent inventions” cannot be claimed in a single application and that, by allowing the divisional applications, (which ultimately resulted in the granting of four patents) the'- Patent Office recognized that there were four . independent ' inventions disclosed in Behimer’s specification; that the specifications of the four patents are substantially identical and that it is only by their claims that the' four patents may be distinguished. Plaintiff concludes that the Patent Office had in mind that there were separate independently patentable features or inventions disclosed, and that the Patent Office intended by the grant of the patent in suit to Behimer to grant protection of an invention which was independent of “postponed cracking” (claims to which were being prosecuted in the original application and on Which patent 2,027,014 ultimately issued.) Plaintiff also argues that, in view of the issuance of four separate patents, predicated upon the Patent Office belief that there were four different inventions disclosed in the Behimer specifications, defendant errs in its repeated references to “the invention” of the Behimer specification,^ — an informed administrative- body having decided that there are at least four inventions to be found there. As to the argument of plaintiff that a “line of demarcation” was observed in the Patent Office between the two conceptions of “postponed cracking” and “clean circulation”, the master made detailed Findings of Fact as to the history in the Patent Office on this point. As the master noted, the same claims were shifted back and forth from the parent application (so-called “postponed cracking”) to the divisional application (so-called “clean circulation”) ; for example, what eventually became claim 13 of the patent which issued on the parent application, first appears as claim 41 in Amendment "C,” December 27, 1922; by Amendment “G” April 10, 1923, it was" withdrawn from the parent application and transferred to the divisional application; there it remained for several years until 1932 when on July 9, 1932 Amendment “M” was filed to the parent application. This amendment contained claim No. 90, the above claim renumbered, same having been that day transferred from the divisional application. Likewise, what eventually became claim 12 of the patent in suit first appears as claim 42 in Amendment “C”, December 27, 1922. By Amendment “G”, April 10, 1923, it was withdrawn from the parent application, became claim 15 of the divisional application (later renumbered 14, later as revised renumbered 51, finally number 12 of the patent in suit.) Plaintiff answers that when the divisional application was filed, all claims, which included return of a condensate to the heating coil were transferred from the parent application to the divisional application; that the claims retained in the parent application were all limited' to “postponed cracking;” -that among the claims transferred to the divisional application was claim 41 of the parent application, comprising postponed cracking and return of condensate, and claim 42 of the parent application comprising return of condensate but not postponed cracking; that in the parent application were claims to postponed cracking per se and in the divisional application were claims to return of condensate with or without postponed cracking. Plaintiff points out that (in the 9 year interval between the divisional application in 1923 and the final submission of claims on July 17, 1932) : 17 claims were added to the parent application, all dealing with postponed cracking; 8 claims were added to the divisional application, all including a step of return reflux. Plaintiff explains the re-transfer from the divisional application to the parent application of the claims in Amendment “M” by the fact that in Interference No. 49,355, Behimer by his disclaimer to Dubbs, had given up the claim of “clean circulation without substantial vaporization in the coil,” and in Interference No. 55,610, Dubbs, by his disclaimer to Behimer, had given up the claim of “clean circulation with mechanical return of reflux;” that Behimer thereafter.-limited all claims in the divisional application to “clean circulation with a forced mechanical return of reflux” and transferred back to the parent application claims limited to postponed cracking broadly, with a general statement as to return of reflux whether by gravity or mechanical means. The Patent Office, on August 2, 1933, had rejected the remaining claims of Behimer on the ground that the process consisted in heating in the coil and cracking in the drum, and did not differ patentably from the earlier Trumble Patent, No. 1,281,844, issued, on October 15, 1918. Thereafter, Texas, as assignee of Behimer, filed an action in the Supreme Court of the District of Columbia, entitled Texas v. Coe, for the purpose of .compelling Coe (who was the Commissioner of Patents) to issue the patent with the claims that had been refused by the Patent Office. The court ultimately decided in favor of Texas and ordered the patent to issue; it was issued on January 7, 1936, as Patent No-. 2,027,014, the “postponed cracking.” patent. The master gave due consideration to what he called the “tortuous and involved record of parent and divisional applications, amendments and transfers,” in an effort to determine whether that record and the subsequent issuance of the “postponed cracking” patent on January 7, 1936 (over 3 years after the date of the patent in suit) indicate a “line of demarcation” observed in the Patent Office between the concepts of “postponed cracking” and “clean circulation” that should affect the construction of the claims in suit read in the light of the specification. He concluded that, on the record here, the issuance of the four patents, and particularly the “postponed cracking” patent, does not indicate that the Patent Office observed a line, of demarcation between the two concepts of “postponed cracking” and “clean circulation”, and does not require or warrant that the claims in suit should be given plaintiff’s broad construction. The master’s conclusion is supported by the record ; I approve it. In support of its contention that the claims in suit should have a limitation as to locus of cracking implied into them, defendant has. introduced in evidence the file wrapper of the parent Behimer application Ser. No. 263,562 which, down to the date of the filing of the divisional application that matured as the patent in suit (April 6, 1923) contains the history of the prosecution of the original disclosure; the file wrapper of the - divisional application Ser. No. 630,242, which is the divisional application that matured as the patent in suit; the file wrapper of Interference No. 49,355, which involved claims from the divisional application Ser. No. 630,242, none of which is included in the patent in suit; the file wrapper of Interference No. 55,610, which involved claims from the divisional application Ser. No. 630,242, from one of which came Claim 22 of the patent in suit, which is a claim in suit here; various excerpts from Interference No. 49,654, which involved claims from the parent application directed to the postponed cracking feature or invention; various excerpts from Interference No. 49,655, which involved claims from the parent application directed to the postponed cracking feature or invention; various excerpts from Interference No. 49,656, which involved claims from the parent application directed to the postponed cracking feature of invention; various excerpts from Interference No. 52, 543, which involved claims from the parent application directed to the postponed cracking feature; and excerpts from the R.S. 4915, 35 U.S.C.A. § 63, action, Texás v. Coe, supra, which involved claims from the parent application directed to the postponed cracking feature or invention. This evidence shows that Behimer -(and plaintiff) repeatedly took positions opposite to those taken here, with respect to the disclosure of the Behimer specification, in the following respects (among others): interpreted the process of the Behimer specification as a coil heating, drum cracking process which solved the carbon problem by preventing cracking, in the coil, thereby removing the cause of carbon formation; interpreted the Behimer process as permitting no substantial cracking in the coil; analyzed the original Behimer specification as clearly teaching heating in the coil without substantial cracking; repeatedly distinguished coil cracking processes such as Dubbs (not the ’629 Patent) and Trumble, from Behimer’sinvention because they dealt -with the carbon problem by limiting the cracking in the processes and by sweeping the carbon from the coil with velocity, whereas Behimer solved the carbon problem by avoiding its cause, namely, cracking in the coil; recognized that the vaporization occurring in a coil cracking operation after pressure release into a drum is not the vaporization occurring in Behimer’s drum where a substantial body of oil is maintained and vaporization results from cracking; recognized that the step of returning reflux to the inlet of the coil was a mere auxiliary refinement in the basic coil heating, drum cracking steps ; recognized the lack of equivalency between cracking in the coil, and heating in the coil and cracking in the drum as in Behimer, by distinguishing other disclosures and references on that ground; recognized that the Behimer process employed a flow of oil whereby the cracking temperature is reached only at the time the oil emerges from the-coil at the hottest part of the furnace, as-contrasted with the opposite flow in coil', cracking processes. Defendant urges that any statements made in the course of the-Patent Office proceedings, regardless of the-issue being discussed and regardless of whether the statements were made with reference to efforts to secure protection of the-postponed cracking feature, should be construed as admissions affecting the construction of the claims in suit. Plaintiff replies-that, among the many alleged admissions as-to “the Behimer invention” in the Patent Office proceedings, defendant has not made reference to a single instance in which Behimer or The Texas Company was discussing the claims in suit; that the only portions-of the Patent Office history which can shed light upon the intended meaning of the-claims in suit is that portion dealing with the claims in suit. There has also been introduced in evidence a Behimer Patent No. 1,923,526, dated August 22, 1933, the so-called Behimer “Coil Cracking Patent”, in the specification whereof Behimer repeatedly indicates that in his application for this-patent (filed August 13, 1925) he has found out for the first time, how to crack oil in the heating coil without causing undue deposits of carbon therein. Plaintiff contends that the patent in suit, like any other written document, is to be construed according to the four corners of the instrument and that, therefore, none of the excerpts is admissible on construction; that a fortiori, the excerpts from Interference 49,654, Interference 49,655, Interference 49,656, Interference 52,543 and 4915 action, Texas v. Coe are inadmissible because they relate to proceedings in the Patent Office and elsewhere after the filing on April 6, 1923 of divisional application 630,242 from which evolved the patent in suit. Defendant’s position is that the construction of the claims in suit here is to be had in the light of the disclosure of the patent specification; that that patent specification is substantially the same specification involved in all of the above interferences and in the 4915 proceeding and forming the basis of the patents thereon as issued, and that the language of Behimer’s disclosure cannot now have a meaning antithetical to the meaning which Behimer and the Texas Company gave to substantially the same language in these antecedent proceedings. My understanding of the law on this issue is this. If the claims, read in the light of the specification, are clear and unambiguous, then the antecedent declarations of the applicant should be regarded as merged in the patent as ultimately issued — that being the contract between the United States and the patentee — and these declarations should have no relevancy to alter or impair that clear unambiguous construction. If, however, the claims, as issued, are not clear and unambiguous, then under the doctrine of Goodyear Dental Vulcanite Co. v. Davis, 102 U.S. 222, 26 L.Ed. 149, the antecedent statements of the applicant would be relevant for the purpose of clearing up this ambiguity; particularly so where they would constitute “declarations against interest.” As above stated, I find no ambiguity in the claims in suit here and regard the language thereof (considering the whole patent, cláims and specifications) as clearly and unambiguously limiting cracking to the drum. However, if the language of the claims themselves, were to be regarded as so ambiguous that it could not be told therefrom whether cracking was limited to the drum or whether cracking was permissible in any zone — then, in my opinion, the proceedings of Behimer in the Patent Office (particularly in connection with his application for the patent in suit) would be admissible for the purpose of explaining this ambiguity; and if admissible for such purpose, they would unquestionably show that Behimer conceived his invention as embracing cracking in the drum alone. Moreover, as cited above, the construction urged by plaintiff for the claims in suit is contrary to the disclosure of the specification. Pláintiff supports his construction by the introduction of extraneous matter* among other things, the “postponed cracking patent”; in my opinion the admissions and conduct in question of Behimer in the Patent Office are also admissible, to refute the construction sought to be put upon the invention and the claims by plaintiff; they corroborate the view heretofore reached (from the language of the patent itself) that cracking in the coil is not impliedly embraced in the claims in suit. Since about 1930, there has been widespread use of coil cracking processes embodying the step of returning reflux to the coil inlet. From this widespread use plaintiff argues that its patent and the claims in suit should be given liberal, i. e. a broad construction and cites Eibel Process Co. v. Minnesota & Ontario Paper Co., 1923, 261 U.S. 45, 63, 43 S.Ct. 322, 67 L.Ed. 523; Smith v. Snow, 1935, 294 U.S. 1, 14, 55 S.Ct. 279, 79 L.Ed. 721; Hunt v. Armour & Co., 7 Cir., 1950, 185 F.2d 722. This general proposition is good law, but it is applicable only to cases where the commercial success, can be fairly regarded as attributable to the invention. The issue here is whether Behimer’s claims in suit are to be construed (as defendant contends) as to heating in the coil and cracking in the drum, or (as plaintiff contends) as to cracking either in coil or drum. For plaintiff to argue in support of its construction (cracking in- any locus) that immediately after the issuance of the patent in suit there had been widespread use and success of a coil cracking process — is begging the question; to regard commercial success of a coil cracking process as an element in construing Behimer’s invention to include coil cracking, would require an initial assumption that the Behimer invention did include coil cracking, otherwise instances of coil cracking use and success would not be referable to the Behimer invention. If Behimer failed to suggest that a coil cracking process was within the area of his invention and if he failed to teach the use of the quenching step and the low liquid level operations (which together with many other factors not embraced by the Behimer patent have made the modern coil cracking process successful), then the success of such a coil cracking practice would have no bearing on the construction or scope of the Behimer patent. The master concluded that it is not permissible to prove A by assuming B to be correct, and then to prove B by A. It is begging the question to rely on the popularity of putative commercial embodiments which are like the accused device but unlike the disclosure of the patent. The case at bar involves the proper construction of the claims in suit, par