A clear statement of this extended litigation will be found in the opinion of Judge Hook, rendered in this case May 1, 1916. 233 Fed. 752, 147 C. C. A. 518, Subsequent thereto a new master was appointed, who, after a hearing, found in favor of the plaintiff in the sum of $182,384.59. Upon exceptions, the District Court disapproved the recommendations of the special master, and ordered a judgment for the plaintiff in the sum of $9,174.12, from which this appeal is taken.
So in this accounting case we find—-
(a) February 16, 1904, decree for accounting, and appointment of Henry H. Denison as special master.
(b) July 29. 1907, master filed his report, finding plaintiff entitled to an award of $132,433.35.
(c) November 29, 1907, report of master disapproved by the District Court, and judgment entered for $1 and costs.
(d) August 16, 1909, this court affirmed (Judge Sanborn dissenting) the finding of the District Court. 173 Fed. 361, 97 C. C. A. 621.
(e) June 7,1912, Supreme Court filed its opinion reversing this court, and remanding the case for further proceedings before a master. 225 U. S. 604, 32 Sup. Ct 691, 56 L. Ed. 1222, 41 L. R. A. (N. S.) 653.
(f) October 21, 1912, Henry H. Denison reappointed special master.
(g) July 9, 1914, master made report, again finding in favor of the plaintiff in the sum of $132,433.35.
(h) December 5, 1914, the District Court overruled report of the master, and entered a decree for plaintiff for the sum of $10,000 and costs, which upon appeal to this court was reversed, and the cause was remanded, with directions to recommit to a master. 233 Fed. 752, 147 C. C. A. 518.
(i) The District Court appointed James L. Hopkins special master, instead of Henry H. Denison. Special Master Hopkins, after a hearing, filed his report, recommending judgment ’for plaintiff in the sum of $182,394.59. o
o (j) The District Court set aside the report of Special Master Hopkins, and ordered judgment in favor of plaintiff for the sum of $9,-174.12.
From such order of the District Court this appeal was taken.
So we find that there were three reports of the special masters, recommending, respectively, an allowance to plaintiff of $132,433.35, $132,-433.35, and $182,394.59. We also find each of these reports disapproved, and findings made by the District Court, respectively, were $1, $10,000, and $9,174.12.
It is not disputed that the defendant manufactured infringing transformers. The essential questions to be determined in this case are: *456(1) How many infringing transformers were manufactured and sold by the defendant? and (2) what was the profit of the defendant upon the infringing transformers sold?
(1) The Burden of Proof.
[ 1 ] Much of the discussion all through this litigation relates to the question as to who has the burden of proof with reference to the issues involved ? We hold that this question, under the facts in this case, was settled by the Supreme Court of the United States in its opinion in this case, where it is said (225 U. S. 604, 620, 32 Sup. Ct. 691, 696, 56 L. Ed. 1222, 41 L. R. A. [N. S.] 653):
“But. when a case of confusion does appear—when it is impossible to make a mathematical or approximate apportionment—then from the very necessity of the case one party or the other must secure the entire fund. It must be kept by the infringer, or it must be awarded, by law, to the patentee. On established principles of equity, and on the plainest principles of justice, the guilty trustee cannot take advantage of his own wrong. The fact that he may lose something of his own is a misfortune which he has brought upon himself; and if, as argued, the fund may have been made by the use of other patents also, for which he may be liable in another case, it is again a misfortune which he has brought upon himself and an instance of a double wrong causing double liability. He cannot appeal to a court of conscience to cast the loss upon an innocent patentee and by judicial decree repeal the provision of Bev. Stat. § 4921, which declares that in case of infringement the complainant shall be entitled to recover the ‘profits to be accounted for by the defendant.’ ”
This language of the Supreme Court had relation particularly to apportionment of profits from a device containing infringing elements and noninfringing elements. We hold, however, that the rule announced is, under the facts in this case, just as necessary for the administration of justice in the determination of the question as to how many infringing transformers were sold as it is to the determination of the question of profit. Where, as in this case, the infringer cannot account for the profits, the owner of the patent can hardly be expected to be able to do so.
It will be observed that the infringing element in the transformers was hidden from view by the metal casing, so that only those who constructed it, or those who should remove the casing, would have any knowledge as to whether the transformer, as constructed, infringed or not. The metal casing was part of the transformer, and was firmly and permanently fastened in place in the manufacturing process. The Westinghouse invention, so far as claim 4 is concerned, was very simple in construction. The core of transformers, had, long prior thereto, been made of small, thin plates, or scales of iron (iaminae), placed one upon another, built up without any spacing between the plates. Westinghouse provided for inserting plugs or pieces of metal between the thin plates at intervals, so as to form spaces in the core; the number of spaces and the size thereof being determined in the process of manufacture. These open spaces permitted oil or other nonconducting liquid to circulate, not only about the core, but through the open spaces in the core, thus reducing the danger of overheating.
*457The core with the coils being immersed in liquid inside the iron case or shell, no one could by mere inspection tell whether the core included spaces or not. The coils, the plates forming the core, and the shell were substantially the same in size, material, and appearance, whether the core had spaces or not. According to the testimony of .defendant’s witnesses, some of the transformers of given types had spaces in the cores, and some not. In fact, it was contended, by some of the men who made the transformers, that the question of spacing was a mere matter of mechanical convenience, and that whether spacing strips were inserted, or not, was determined by the worlonen who put on the case or shell. In fact, it is apparent from the letter of Schwedtmann, the manager of the defendant, written on July 2, 1902, to the factory foremen, that in a completed transformer spaces in the core could be eliminated, thus removing the infringing element. This letter is as follows:
“Mr. A. H. Timmerman,
“Mr. S. E. Joliannesen,
“Mr. Selinger:
“In the future, we must not under any considerations use in oil-filled transformers, small or large, spacing strips between the laminae. Tbe Westingliouse Company has a patent on such a construction, and we are enjoined from the use of it. Please understand that it is not in any way or shape to affect or interfere with, our using such a construction in dry or air-blast transformers. The combination of spaced laminae and oil filling is patented. This holds good for every one and all transformers that will be shipped out of the house after this morning. The injunction was served on us a minute ago, and you must be very, very careful about this. I suggest that we, with standard transformers now in the house and ready for shipment, either pull out the spacing strips, or leave them in and fill the spaces in between the laminae with the proper kind of compound. I would suggest sulphur and feld [sparl. If the meaning of this note is not absolutely clear to you, come down and talk it over with me, and I .ask Mr. Timmerman in particular to see that the transformers now in stock are marked in such a way that they will not be taken and sent out by the shipping clerk, or the foreman of the packing department, without first being changed.”
So it is quite apparent that only the men who actually constructed, the transformers knew, or could, know, whether they contained the infringing element. There were no distinguishing marks, so far as the record shows, from which'even the men in the factory could continue to have knowledge as to which transformers of any type had spaces in the core, and which did not.
The Wesiinghouse patent was granted in 1887. Suit for infringement was commenced May 10, 1900. While this original action for infringement was against the Union Carbide Company, the defendant aided in the defense because it had manufactured the alleged infringing device. November 11, 1901, the District Court entered a decree sustaining the claim of infringement, which was affirmed by the Court of Appeals May, 1902. Injunction was served upon this defendant July 2, 1902, the date Schwedtmann wrote the foregoing letter.
The first testimony taken in this action for an accounting was subsequent to May 31, 1904. During the time of infringement, 1896 to 1902, plaintiff had no access to the factory of the defendant, or the books or records of the defendant, and after infringment, and up to *458the time of taking testimony in this case, plaintiff had no knowledge of the defendant’s business, except as disclosed in the infringing litigation. So that the number of infringing transformers manufactured and sold, and the cost, selling price, and profits, were all known only to the defendant.
When it came to trial of this case, more than eight years after the infringement commenced, the defendant was unable to produce a single book or record, or fragment of paper, indicating either the number of transformers which infringed, or the profits upon the infringing transformers, or the portion of cost, selling price, or profits, which should be attributed to the infringing element. The only records disclosed are those showing the total number of transformers manufactured and sold, having nothing to indicate which infringed and which did not, and the general books of account, which are likewise barren of any indication as to the two important questions in this case: (1) How many infringing transformers were made and sold; (2) the profits upon the transformers sold, or upon any element included in such transformers.
There were some records kept. It was the practice in the factory to make advance estimates of “the labor and material values, and to superpose upon those values the amount to cover general operating expenses.” Layman, the general manager, states that—
“It was the practice of the company to make one inventory a year. I think sometimes two a year were made during the period of this schedule” (which included a list of the infringing transformers).
One of the employés testified that these inventories were bound in volumes and kept in the vault. This is not denied. A former manager testifies:
“It was customary to make a record of the manufactured stock, etc., every six months,” and that “the part of the inventory which I had to do with, gave the factory cost of the transformers,” and that “it would he possible by reference to the inventory to get at the cost of the various transformers made.”
Another employe testifies:
That an exact account was kept of the “price of labor of each transformer,” and that he kept “a record of the price of labor,” and “the exact amount of labor spent on each transformer.”
Layman, the general manager at the time of the trial and long prior thereto, testifies:
That the records were burned. “We burned all of the records.” “Those records were destroyed five or six years ago.” (He was testifying November 10,1905.)
• He says that the records were destroyed within a year or two from the time they ceased infringement, and he swears that—
“The company has in its possession at this time absolutely no reliable data on which we could arrive at the actual cost of this apparatus.”
The special accountant employed by the defendant testifies that there was not a single item of record evidence with reference to cost of the transformers. This destruction of records made it impossible, not only for the plaintiff to prove the facts in issue, but left the defendant with- ' *459out proof, except vague estimates, uncertain recollection, and guesswork. So that we have a case in which, not only was the evidence as to infringement and as to costs and profits solely in the possession of the defendant, but in which the defendant destroyed such evidence.
Defendant contends that their records were not accurate, and that a new system was adopted before the records were burned; but they were the records upon which the business was conducted and the transformers made, and upon which prices were fixed—at least in part— during a long period of years. Under the foregoing circumstances, to hold that the plaintiff has the burden of proof either as to the number of infringing transformers sold, or as to the profits or segregation of profits, would be a-denial of justice, and the situation is presented in which, as the Supreme Court said (225 U. S. 604, 620, 32 Sup. Ct. 691, 696, 56 L. Ed. 1222, 41 L. R. A. [N. S.] 653)
“From the very necessity of the case one party or the other must secure the entire fund. It must be kept by the infringer, or it must be awarded, by law, to the patentee. On established principles of equity, and on the plainest principles of justice, the guilty trustee cannot take advantage of his own wrong. * * He cannot appeal to a court of conscience to cast the loss upon an innocent patentee, and hy judicial decree repeal the provision of Bev. Stat. § 4921, which declares that in case of infringement the complainant shall be entitled to recover the ‘profits to be accounted for by the defendant.’ ”
(2) The Accounting by the Defendant.
Strictly speaking, the defendant made no accounting of the number of infringing transformers, or the profits, or the portion of profits properly due for the use of the infringing element. The evidence as to the number of transformers is so vague and uncertain that it is with the greatest difficulty that any fair estimate thereof may be arrived at. There was no real attempt to segregate profits—the defendant undertaking instead to prove the infringing element was worthless.
[2] The defendant had notice of the claim of an infringement as early as 1897, and continued infringement from that time until July 2, 1902. Defendant aided in defense of the action against the Union Carbide Company commenced May 10, 1900, arid continued such aid through the District Court and the Court of Appeals. Infringement was not stopped until the injunction was served, July 2, 1902. Under these circumstances, any contention that the invention was without utility is entitled to little consideration. In any event, it was not a question of whether the patent had utility; that was settled in the infringement case. It was a question as to what amount in dollars and cents, commercially speaking, the invention added to the price received for the transformers.
(3) The Dayman Schedule.
Much of the controversy which has brought this case under the consideration of two special masters (one of whom filed two separate reports), to the District Court three times, and into this court twice before the present hearing, and to the Supreme Court of the United States once, centers upon what is known in this record as the “Layman Schedule.” Upon the first hearing before the special master, it seems *460to have been assumed that the plaintiff had the burden of proof. The hearing was commenced on June 29, 1904. No account of any kind, or report of any kind, was filed by the defendant. The plaintiff called as a witness Waldo A. Layman, who had been treasurer of the defendant company since 1898, and manager of the company since 1902. He had been identified with the defendant company since 1892 as draftsman, engineer in charge of testing work, assistant superintendent, and assistant general manager.
Counsel for plaintiff proceeded to interrogate this manager as to the number of infringing transformers which had been made by the defendant. The witness had nothing more than “preliminary figures” relating to 6,524 transformers, and considerable time was devoted to discussion as to the facts with reference to the number of transformers made and sold, and to whom sold, etc. Finally, on July 13, counsel for plaintiff suggested, in order to save time, that the witness produce at a later session a complete transcript of all. sales of inf ringing transformers by the defendant company from June 24, 1896, up to and including July 12, 1901. Counsel for defendant agreed that such a transcript should be made and produced, and on September 26, 1904, some 2% months later, the transcript was brought before the master. This transcript is known as the “Layman Schedule.” Mr. Layman did not prepare it personally, but he testified that—
“It has been made under my instructions, and by clerks in wbom I have confidence, and to my best knowledge and belief it is correct.”
Later, when this schedule was attacked by the defendant as erroneous, stress was laid upon the fact that Miss Eagan, the stenographer for the master, who took the testimony in the hearing, was active in preparing the transcript—counsel sometimes referring to the fact that the Layman schedule was made by the representative of the master. But we find nothing in the record to justify any conclusion that Miss Eagan acted in any other capacity than as a mere stenographer or accountant in putting into the transcript the items given to her by clerks in whom Mr. Layman had confidence. This schedule reported something like 6,000 transformers sold, for a total sum of over $800,000. Upon the trial Mr. Layman positively asserted a number of times that this schedule contained only transformers which infringed the Westinghouse patent. He testified that he had not checked it over in detail, but that he was satisfied that it contained only infringing transformers. He understood the questions in issue, and endeavored at that time to disclose what the company records showed as to sales of infringing devices, and only such as did infringe.
After the report of the master, the decree of the District Court, and the appeal taken to this court, in order to shorten the record, a stipulation was entered into (Transcript of Record, 42), in which the parties agreed:
“That said two volumes of tabulations (which were not to be printed) contained a list of more than 6,000 transformers sold by the Wagner Electric Manufacturing Company, appellee, from and after June 24, 1S96, up to and including November 14, 1901, being a list of transformers manufactured and sold by the Wagner Electric Manufacturing Company, appellee and defendant, *461each of which transformers embodies in its construction the invention claimed by the fourth claim of the Westinghouse patent in suit, No. 366,362, dated July 12, 1887, being infringing transformers manufactured and sold by the defendant and which are the transformers referred to in the master’s report in this case, and concerning which transformers the master in this ease was ordered to take and state an account by the interlocutory decree entered in this cause by the Circuit Court on the 16th day of February, 1904, * * * and is the same tabulation, record, or report thereafter referred to by Waldo H. Layman, one of the defendant’s witnesses, in his testimony taken in this ease, and that said defendant’s witness Waldo H. Layman admits, in questions and answers 84 and 85 of his testimony before the master, said tabulated report or statement covers all transformers made and sold by the Wagner Electric Manufacturing Company from and after June 24, 1898, up to and including November 14, 1901, which transformers embody in their construction the invention described in claim 4 of the Westinghouse patent in suit, No. 366,362, dated July 12, 1887.”
The total volume of the company’s business during such period ($2,-314,774.75) and the amount of money ($955,271.76) actually received by the defendant company for infringing transformers was also agreed to in this stipulation. So at the close of the first hearing before the master, and when this case first came to this court, there was no dispute about the number of infringing transformers, and no dispute about the amount of money received- for them by the defendant. The master as aforesaid allowed the plaintiff to recover profits in the sum of $132,-433.35; the District Court held that nominal damages only could be recovered. This decree was affirmed by this court (Judge Sanborn dissenting). The District Court and this court were in error as to the burden of proof, which error was corrected by the Supreme Court, supra. When the Supreme Court .remanded the case, it was ordered:
“That the case be recommitted to a. master for a new hearing on all the questions involved in the original reference and on evidence already submitted and such additional testimony as may be offered.”
(4) The Williams Schedule.
Upon the second hearing before the master, under the mandate of the Supreme Court, he assumed that the Dayman schedule, fixing the number of infringing transformers, and the stipulation aforesaid, were conclusive, which, of course, was erroneous, and so held by this court (233 Fed. 752, 147 C. C. A. 518), which remanded the case—
“with direction to recommit it to a master for a new hearing on all the questions involved in the original reference, and on evidence already submitted and such additional evidence as may be offered.”
Thereupon the District Court appointed a new master, whose report is now before this court.
Upon the second hearing, the Supreme Court having placed the burden of proof upon the defendant, the Wagner Company proceeded to attack the Layman schedule and stipulation aforesaid, and the principal witness produced was one John R. Williams, an accountant, whet was permitted by the master to present a transcript from the card index and record of the defendant, containing a total list of all the transformers manufactured and sold by the defendant—infringing and noninfringing. Of course this witness had no knowledge, and no means of *462knowledge, except hearsay, as to which of the transformers infringed. This transcript disclosed some 16,000 transformers, which, of course, was taken from the same records from which the Layman schedule was made. Layman was recalled, and in a very feeble, indefinite way asserted that the schedule which he had prepared for the first trial was incorrect. As to one of the types, M, prominent under the issues, he makes it no stronger than:
“My understanding is that all type M transformers were alike in construction.”
He does assert that he knows that the schedule includes transformers not oil-filled. Other witnesses were also introduced by the defendant to prove that the Layman schedule was erroneous.
[3] Now what weight should be given to the Layman schedule? It was not conclusive. It was evidence introduced by the complainant, but it was evidence of the manager—later the president—of the defendant. It was evidence taken from the books of the defendant. It was supported by the written stipulation of the defendant. It was not hurriedly prepared—at least 10 weeks having been devoted to its preparation. Notwithstanding all this, the defendant had the right to prove that it was erroneous. But defendant had the burden of proof as to the number of transformers before any evidence was introduced. In addition to this, it had the burden of overcoming the weight of the schedule and stipulation; so that, when it came to the second hearing, it must be confessed that only reasonably clear and convincing evidence contradicting the Layman schedule would be sufficient to sustain the burden resting uppn the defendant.
[4] Furthermore, the court cannot shut its eyes to the well-established rule that—
“So far as it depends upon conflicting testimony, or upon the credibility of witnesses, or so far as there is any testimony consistent with the finding, it [the master’s report] must be treated as unassailable.” Davis v. Schwartz, 155 U. S. 631-636, 15 Sup. Ct. 237, 239 (39 L. Ed. 289).
See, also, Tilghman v. Proctor, 125 U. S. 136, 8 Sup. Ct. 894, 31 L. Ed. 664; Adamson v. Gilliland, 242 U. S. 350, 37 Sup. Ct. 169, 61 L. Ed. 356.
To review the evidence offered by the defendant upon the question as to the number of infringing transformers would be fruitless. Any deductions from the Layman schedule would have to be based upon guesswork. In reaching this conclusion, we give to the Layman schedule and stipulation only that weight and consideration to which it is entitled as an item of evidence in this case.
[5] Much has been said by counsel about type M being noninfringing, and stress is laid upon the claim that type M was of the same construction as was the device before Judge Adams, who held ([C. C.] 129 Fed. 604) that it did not infringe. The transformer before Judge Adams did not have spaces; but, bearing in mind the fact that having spaces involved absolutely no change in structure, except to omit the space plates or plugs, adding additional iron plates, if desired, it may easily be seen that, of any two type M transformers made on the same *463day, one might infringe and the other not. M was a prominent type. It was included in the Layman schedule. No reason is suggested by any witness why spacing was not used in M as in others of the same size. That a change in M was made is indicated in the catalogue statement that from December 1, 1902, defendant was prepared to supply two forms of standard transformer—M and M H. And most convincing that all the transformers using oil did in fact infringe is the statement by Layman (S. C. R. 53):
'T have followed this entire litigation (beginning with tbe Carbide Case in 3900) very closely. I have had frequent consultations with counsel in the preparation of the defense and in the preparation of the argument (in the same case). I was present in the Court of Appeals when oral argument was made in the case referred to. I have also many times discussed with counsel for the defense means to be employed by the Wagner Company in modifying apparatus in event of an adverse decision so as to free the transformers made by the Wagner Company from the terms of claim 4 of this patent here in suit.”
Under these circumstances, the inclusion of the M transformers in the Layman schedule could hardly be an accident. In the letter of July 2, 1902, heretofore quoted, the manager instructs the men that—
“In the future we must not under any considerations use in oil-filled transformers, small or large, spacing strips between tbe laminae. * * 0 This holds good for every one and all transformers that will be shipped out of the house after this morning. ® * * I suggest that we, with standard transformers now in the house and ready for shipment, either pull out the spacing strips or leave them in and fill the spaces in between,” etc. “I ask Mr. Tim-merman in particular to see tbat the transformers now in stock are marked in such a way that they will not’ be taken and sent out by the shipping clerk, or the foreman of the packing department, without first being changed.”
There is not a suggestion in the letter that any transformers not infringing are in the factory. The manager refers to "the transformers now in stock.” He insists:
“That the transformers now in stock” “will not be taken and sent out by the shipping clerk or the foreman of the packing department, without first being changed.”
No suggestion that other transformers which did not infringe should be sent out. Why should Layman be solemnly discussing with, counsel in the case “means to be employed by the Wagner Company in modifying apparatus in event of an adverse decision, so as to free the transformers made by the Wagner Company from the terms of claim 4 of .this patent here in suit,” if the company was at that time making transformers which did not infringe?
The impression which one gets from reading the entire evidence is that all oil-filled transformers had spaces, except where, as a matter of “mechanical convenience,” the spaces were omitted. The burden being upon the defendant—the defendant having the further burden of overcoming the weight of the Layman schedule and the admissions in the stipulation—we are convinced that this court should not interfere with the findings of the master as to the number of transformers which infringed.
*464(5) Profits.
[6] There are at least two methods by which profits for infringement may be proven: (1) By the actual production cost, selling price and actual profits, as shown by the books of the company; (2) by the testimony of experts.
The first method may be employed with satisfaction, where the infringer is manufacturing, or selling, only the infringing article, and where there is no contribution to the profits from noninfringing elements in the article produced and sold. But where, as in this case, the defendant is manufacturing and selling many articles besides those which infringe; where, as in this case, no books of account are kept, showing the cost of any of the articles; where, as in this case, inventories and cost data have been burned by defendant; where, as in this case, the books of account containing general accounts of the general business are inaccurate, and, as contended by the defendant herein, erroneous in many particulars—in such a case, an attempt to prove the amount of profit derived from the infringing element in one of the articles sold must utterly fail. It is not only impracticable, but it is impossible, to arrive at any conclusion with that degree of certainty which is required in a court to establish a fact in issue.
[7] Evidence to separate or apportion the defendant’s profits “between the patented features and the unpatented features” must be reliable and tangible, and not conjectural or speculative. Garretson v. Clark, 111 U. S. 121, 4 Sup. Ct. 291, 28 L. Ed. 371, quoted in opinion of the Supreme Court in this case (225 U. S. 604, 32 Sup. Ct. 691, 56 L. Ed. 1222, 41 L. R. A. [N. S.] 653).
[8] Under circumstances aforesaid, the burden being upon the defendant, as held by the Supreme Court in this case, the defense must fail, and the plaintiff is entitled to recover the entire profit upon articles sold which contain the infringing element. If the defendant, suffers loss under this rule, it “is a misfortune which he brought upon himself.”
“Having, by books and other data, proved to the satisfaction of the master the existence of profits, the plaintiff had carried the burden imposed by law, and established every element necessary to entitle it to a decree, except one. As to that, the act of the defendant had made it not merely difficult but impossible to carry the burden of apportionment. But plaintiff offered evidence tending to establish a legal equivalent. It had proved the existence of a fact which, whether treated as a rule of evidence or as a matter of substantive law would entitle it to a decree for all the profits.” 225 U. S. 604, 618, 32 Sup. Ct. 691, 695 (56 L. Ed. 1222, 41 L. R. A. [N. S] 653).
The testimony of Accountant Williams and other testimony has been brought into the case since the Supreme Court of the United States expressed itself as aforesaid, but with the additional evidence the record in our judgment is now without sufficient proof from any áccounts or books to enable any court to segregate the profits upon the infringing element. The evidence is not “reliable and tangible”—it is “conjectural or speculative.”
The second method aforesaid, proof by experts, it is pointed out by the Supreme Court in this case, must be employed where other methods *465of proof fail. The court quotes from Chicago, M. & St. P. R. Co. v. Tompkins, 176 U. S. 178, 20 Sup. Ct. 340, 44 L. Ed. 417, that it is permissible to introduce “the testimony of experts as to the relative cost of doing a local and through business,” and states:
“The converse is true. What is permissible in an effort to separate costs may also be done in a patent case, where it is necessary to separate profits.”
A review of patent accounting cases in which weeks and months have been devoted to the hearing of testimony of accountants upon “original investment,” “additional investments,” “depreciation,” “experimentation,” “losses upon defective manufacture,” “total income,” “interest upon whole investment,” “labor,” “material,” “tools and machinery,” and a dozen other correlated subjects, with confusing contradictions of bookkeepers and accountants, is convincing that the Supreme Court has suggested a method by which, in patent accounting -cases, it is possible to arrive at the approximate truth in regard to profits in a brief and satisfactory manner. It may not be necessary to resort to experts in some cases, where the facts appear from books of account; but as a rule the cases which burden the courts—the cases in which' delay and expense of litigation discourage and dishearten litigants in patent accounting cases—are those in which books, accounts, and records lead only to endless confusion.
In the nature of things, expert testimony will not lead to exact results. The courts recognize “the impossibility of reaching a conclusion that is mathematically exact”; but men who are qualified by experience in the manufacture and sale of (in this case) transformers certainly could enlighten the court upon the question as to the profit in a given transformer, and likewise what portion of such profit was attributable to the different elements therein, including the infringing element. This way was open to the defendant in this case. The Supreme Court had in this case so expressed itself, but the defendant offered no such testimony; it relied principally upon accountants, and upon witnesses, whose testimony was intended to prove that the infringing element was worthless.
So far as books and accounts, and accounting, is concerned, the defendant relies to a large extent upon Williams; but no bookkeeper or accountant employed by the defendant through these many years, no man or woman who kept the books of account for the defendant, was placed upon the witness stand, and no. explanation is given .as to their silence. This is very significant, in view of the fact that, upon the first hearing, Layman, the manager, made a statement of the total sales and total profits—brought the statement into court, and testified that it was correct (S. C. R. 335), and then fortified this by an express stipulation in writing, heretofore referred to. The burden being upon the defendant, under the circumstances in this case, to segregate the amount of profits derived from the infringement, it has failed, and the plaintiff is therefore entitled, under the rule of the Supreme Court in this case, to the total profits upon all infringing transformers.
[9] The only satisfactory evidence of the amount of profit upon each transformer is that of Johannesen and Foster, who, while they were *466former employés of the defendant, at the time of trial in the employment of the plaintiff, were shown by Layman and Schwedtmann to be conscientious, honest men. Johannesen was in the employ of the defendant company from July, 1893, to 1895, in the testing department, and from 1895 until 1902 was engineer of the transformer department. He testifies that every operation in the making of the transformer was itemized under a separate heading—the winding of the coils, the cutting and annealing of the iron, the process of insulation, the mounting of the transformer, the packing, the copper contained in the coils, the iron contained in the core, the case, the various forms of insulation, the terminal cables, etc. The cost of labor and the material as to the foregoing items, “was gotten out in tabulated form,” copies sent to the person in charge of the sale, blueprints made and tracings, etc. He testifies that inventories were made January 1 and July 1, each year. When' he left the employment of the defendant, the data in the office would enable him to arrive at the costs and profits. He testifies that—
“During tlie time I was with the company a rule prevailed which is to add a percentage of 25 to the factory cost, and this rule was always used as a basis for ascertaining the selling price.” “It was the practice to take the flat cost of labor and material, and add thereto a certain percentage, ranging from 25 to 40 per cent., the sum of which item represented the total factory cost, and to that sum 25 per cent, was added to make the selling price.”
His evidence further shows that 25 per cent, was the usual profit added to the total cost. The witness produced two blueprints from original tracings worked out by the witness and his assistant, showing in minute detail the cost of manufacturing transformers. These two blueprints in the custody of this witness.appeared to be the only two which survived the burning of the records, estimates, accounts of cost, and material during the many years of infringement.
Witness Foster was employed by the defendant from 1896 until May, 1902, assisting Johannesen as engineer in the preparation of “data relative to transformers, also working up costs in detail.” He was transferred to positions in charge of the various transformers— testing departments for approximately a year and a half, then back to the engineering office assisting in designing transformers, etc., and again transferred to the head of what was known as the production department and quotations department, which he held until he left the employment of the company. He also testifies as to the complete records kept, as to the estimates of costs of labor and material, as to the inventories taken January and July, and without question he shows his competency to testify as to the percentage added to the cost of production.
Defendant in no manner denies the service of these men, and the making and keeping of the records of the costs and expenses, but denies the accuracy; but in view of the fact that the burden is upon the defendant, and in view of the many years during which the factory methods were as testified to by these two witnesses, which is not disputed, and in view of the fact that the defendant was doing an extensive business, and in view of the destruction of the records and inventories by the defendant, the court is not justified in holding that the defendant has sustained the burden imposed upon it in this case. *467On this record the court is not justified in rejecting the finding of the master that the profit should be computed at 25 per cent, of the selling price of the transformer.
The conclusions of the court herein expressed render it unnecessary to consider other and interesting legal questions discussed by counsel.
The ruling of the District Court, in setting aside the report of the special master and ordering judgment in favor of the plaintiff for the sum of §9,174.12, is reversed, and the finding of the master is confirmed, and decree is ordered in favor of the plaintiff and against the defendant, in the sum of §182,394.59, as found by the special master. This sum to bear interest at the rate of 6 per cent, from the date o£ the filing of the report of the special master.
The above opinion was prepared in outline and substance and submitted to Judge HOOK, who prepared the dissenting opinion following and asked that it be filed with the majority opinions