NORVELL, Justice.
This is a suit to recover sums of money allegedly due under a gas processing con[379]*379tract. Plaintiffs, M. B. Chastain and others, recovered judgment against defendants, Champlin Oil & Refining Company and others, for the sum of $118,076.25. The Court of Civil Appeals affirmed in the main hut modified so as to permit recovery for only such sums as were not barred by the four-year statute of limitations. 379 S.W.2d 938.
The Issues in the Case
While there are a few subsidiary problems, hereinafter mentioned, the two main issues before us relate to the petitioners’ contentions that the Court of Civil Appeals erred (1) in holding that the trial court was correct in refusing to give petitioners’ requested special issues designed to submit petitioners’ theory that the contract sued upon should be reformed because of a mutual mistake, and (2) in holding that the trial court correctly disregarded the jury’s answers to special issues designed to submit petitioners’ theory that respondents should not be allowed to recover upon the contract as written because of an asserted equitable estoppel. As both these holdings were made as a matter of law, we are required to view the facts from the standpoint most favorable to petitioners. In many respects, however, the facts are established by the undisputed evidence.
Statement of the Facts
The petitioners here and defendants in the trial court are Champlin Oil and Refining Company, Hugh M. Briggs, Ben R. Briggs, Clyde H. Alexander, Crestón H. Alexander, individually and as independent executor of the estate of Euna M. Alexander, deceased, Helen Mae Dimit and Charles E. Dimit and Norman V. Kinsey, Jr. Champlin Oil and Refining Company was the operator of the processing plant involved in this litigation and acted for and on behalf of its co-defendants, and hereinafter such parties will for the most part be referred to as Champlin. The plaintiffs, respondents here, are M. B. Chastain, Vincent A. Hughes, John P. Costello and Bennett L. Wooley. M. B. Chastain acted for and on behalf of his co-plaintiffs and this group of litigants will hereinafter be referred to as Chastain.
The contract which is the basis of this lawsuit was negotiated during the year 1956 by M. B. Chastain and Charles B. Johnson, Jr., the Champlin Vice President in charge of the company’s processing business. For a number of years prior to this time, Champlin had operated a processing plant near Carthage, Texas, which extracted and manufactured from natural gas certain liquid petroleum derivatives generally referred to as “plant products” which consisted of propane, iso-butane, normal butane, liquid petroleum gas, gasoline, fuel oil and kerosene. Champlin’s predecessor, the Chicago Corporation, had negotiated an agreement with the Panola County Royalty Owners Association evidenced by a letter dated June 8, 1948, under which a procedure was established whereby the amount of liquid chemical elements making up the manufactured products and contained in the natural gas submitted to the plant could be measured. This measuring process is a highly involved technical procedure from a chemical engineering standpoint and not one easily understood even by experienced producers of petroleum. The measuring device or method set out in the Panola County Royalty Owners Agreement has been in use at Champlin’s Carthage plant since 1948 and will be referred to as the “plant formula.” In addition to the gas which it produced, Champlin also processed the gas produced by other operators in the field, and the purpose of the “plant formula” was to enable the company to return to the gas producers in the form of processed or manufactured products all of the chemical elements contained in the gas produced by them. For its processing service, Champ-lin received a percentage of each producer’s manufactured products. This percentage varied somewhat depending upon the nature of the gas processed and was a subject of [380]*380negotiation between the processor and the producer.
Prior to the time of the Chastain negotiations in 1956, Champlin had prepared a form of contract relating to its processing operations. However, through oversight or misadventure, paragraph No. 8 of the contract, instead of setting forth the Panola County Royalty Owners’ formula (the plant formula) , embodied an older formula somewhat similar in form and wording, but different in several respects. Champlin says that this formula was an outmoded one, used primarily for the purpose of ascertaining the amount of condensate only contained in gas, rather than one designed to measure the various forms of liquid hydrocarbons actually produced by the plant. The Champ-lin plant was modified in 1948 so as to extract not only condensate but also propanes, butanes and other products classified as “plant products.” The formula actually set forth in the contract will be hereinafter referred to as the “contract formula.” It is evident that such formula was placed in the contract through misadventure for since the year 1948 no allocation of “plant products” has been made by Champlin in accordance with the “contract formula,” but on the contrary the “plant formula” had been used to measure the “plant products” produced and was being used at the time the Chastain contract was negotiated.
In his negotiations with Johnson, the Champlin Vice President, Chastain contended that he should be charged a comparatively smaller processing percentage because the gas from the four wells which he proposed submitting to the processing plant was rich gas in that it contained liquid elements in excess of the average producing well in the area. There was little discussion as to the terms of the measuring formula to be employed in evaluating Chastain’s gas, although there is testimony that Chastain and his associates made some investigation relating to the “contract formula.”
Certain changes and corrections were made in the contract submitted by Champlin and thereafter it was finally approved by the contracting parties. The Chastain wells started producing to the plant in the summer of 1957. Each month thereafter, Champlin sent Chastain its regular accounting statement based upon the “plant formula” which showed the actual allocation of the total plant recovery of all liquids from every well (including Chastain’s) producing to the plant.
In 1958, Humble Oil and Refining Company and Pan American Petroleum Corporation conducted an audit of Champlin’s books and called Champlin’s attention to the fact that the allocations being made by Champlin in accordance with the plant allocation formula were not in accordance with the formula contained in the contracts which it had with some 165 producers. Champlin then was confronted with a decision as to its future course of conduct. Should it continue to allocate according to the “plant formula” or should it attempt' to adjust to the “contract formula” and in so doing, make further payments to some producers and attempt to recover a portion of the payments theretofore made to the other producers? It seems that generally speaking, the “contract formula” would call for more payments to “rich gas” producers than would the “plant formula.” It does not appear, however, that the “plant formula” failed to allocate to the “rich gas” producer, all the liquid hydrocarbons contained in his gas.
Faced with this dilemma, Charles B. Johnson, on behalf of Champlin with the approval of the Company’s general counsel, prepared and mailed the following letter, dated September 12, 1958, to all 165 producers, including Chastain, who were affected by the variance between the contract and plant formulae:
“Humble Oil & Refining Company and Pan American Petroleum Corporation have just completed an audit of Champlin’s books covering our Carthage Plant operations for the period from August 1, 1955, through Decern-[381]*381ber 31, 1957. Since commencement of processing at the Carthage Plant in 1946, these two companies have audited the operation of this plant for themselves and on behalf of others four separate times starting in the year 1950.
“During this most recent audit (just completed in 1958) a question was raised for the first time as to the language in the processing agreements as compared to the actual procedure used by Champlin for the allocation of plant liquids which procedure was agreed upon and set forth in a letter agreement dated June 8, 1948, between the Panola County Royalty Owners Association and The Chicago Corporation (now Champlin Oil & Refining Co.) and a letter from the Royalty Owners Association to The Chicago Corporation dated June 11, 1952.
“The procedure used in allocating plant liquids since this agreement was made with the Royalty Owners Association is fully reflected in the ‘Gas and Liquid Production and Disposition Report’, complete copies of which you receive monthly. After a review of the matter, Humble agrees with Champlin that this procedure, which has been in actual use since 1948 and as adjusted slightly in 1952, is most equitable and after reviewing the entire matter Pan American expresses no disagreement with the procedure.
“Certainly, a prime requisite for a fair and equitable allocation of liquid products derived from a commingled stream of gas is that the allocation method and procedures for each and every source of gas be identical. We have, therefore, been employing the procedure worked out with the Royalty Owners Association consistently during all this time, and all parties have been fully advised of the allocation through the monthly reports mentioned above.
“We take this opportunity of advising you that it will be our practice to continue to employ the aforementioned procedure as to all producers connected to our plant. If you have any question as to the procedure as heretofore employed, and which we propose to continue, or as to any other matters pertaining to our processing agreement with you, we will be glad to discuss the matter with you. Unless we hear from you to the contrary within thirty (30) days, we will consider that our suggestion for continuing this procedure meets with your approval.”
This letter constitutes the focal point of the legal inquiry before us. Chastain made no reply to this letter within thirty days from receipt of such letter, nor did he make any suggestions or objections to the allocating procedures which were continued in accordance with the “plant formula” until sometime in 1961. About March of that year, one Dick Castleberry sought and obtained a meeting in Dallas with M. B. Chas-tain. Castleberry was accompanied by John McNamara, an attorney of Waco, Texas. At this meeting, Chastain was told that Champlin owed him money and Castleberry said that he had proof of this. An agreement was made whereby in return for information, Castleberry was to receive 40 per cent of any money owed to Chastain by Champlin that Chastain might collect. Several weeks later, Castleberry and a certain Mr. Kinney, formerly an officer of Champlin, met with Chastain, an audit of Champlin’s books was made and this suit instituted.
The Contention of Mutual Mistake
In support of the contention that the insertion of the allocation formula actually contained in the written contract was the result of a mutual mistake, Champlin requested the submission of two issues, inquiring if (1) the parties “intended that the liquid content of the gas from the Chastain wells should be determined by the same allocation method as the Champlin plant was [382]*382using to determine the liquid content of the gas from all other wells producing to the plant,” and if (2) the parties “as a result of mutual mistake, believed, at the time they signed it, that the contract language correctly described the allocation method being used to determine the liquid content of the gas from all wells producing to the plant.”
For the purpose of deciding the point of mutual mistake, we may consider (despite respondent’s argument to the contrary) that Champlin actually made a mistake in the technical sense of the term when it prepared its contracts and inserted therein a discarded measuring formula rather than that set forth in the letter contract with the Panola County Royalty Owners Association. We may also assume that both Cham-plin and Chastain intended that Chastain should receive all of the liquid hydrocarbons which his gas contained and that the use of the Panola County Royalty Owners’ formula (the plant formula) would accomplish this purpose with accuracy. It may well be that Chastain assumed or believed that the formula contained in Paragraph 8 of the contract was the allocation formula being used at the time the contract was negotiated. This would be a natural assumption. It would be unusual, to say the least, for a processing company to offer to contract upon an allocation basis different from that in actual use at the time such offer was made, particularly when there was no discussion of a proposed change in plant operation. It further seems self-evident that a uniform method of measurement and allocation of liquid hydrocarbons is highly desirable if not essential to a processing operation of the kind Champlin was conducting. The use of two or more different for-mulae could and probably would result in the allocation of more or less than 100 per cent of the liquid hydrocarbons taken from the gas processed at the plant.
However, Champlin’s claim of mutual mistake must necessarily fall because of a failure to prove that Chastain agreed that the liquid hydrocarbons in his gas should be measured by the “plant formula”. The equitable reformation of a written contract is based upon the premise that a contract was actually made, but the written memorandum thereof, because of a mutual mistake, does not truly reflect the actual agreement of the parties. “Reformation is a proper remedy when the parties have reached a definite and explicit agreement, understood in the same sense by both, but, by their mutual or common mistake, the written contract fails to express this agreement.” Black on Rescission and Cancellation, Sec. 11, cited with approval in Marlin Associates v. Trinity Universal Ins. Co., 226 S.W.2d 190 (Tex.Civ.App. 1950, no wr. hist.) and Continental Casualty Co. v. Bock, 340 S.W.2d 527 (Tex.Civ.App. 1960, ref. n. r. e.). See also 49 Tex.Jur.2d Reformation of Instruments, § 9.
In Indemnity Ins. Co. of North America v. W. L. Macatee & Sons, 129 Tex. 166, 101 S.W.2d 553 (1937), this Court held that: “One is presumed to intend what he does or undertakes to do by the terms of a written instrument voluntarily signed by him.” We are therefore required to start with the presumption that Chastain intended to contract with reference to the allocation formula contained in paragraph 8 of the contract which he signed. He examined the contract. He and his associates had others examine it for him. It is undisputed that the method of liquid hydrocarbon allocation was not discussed between Johnson and Chastain. Every species of belief and assumption will not afford a basis for relief by way ■ of reformation. Many contracts are made and enforced despite some collateral misapprehension which may have an important bearing upon the contractual situation. Despite hardship, relief by reformation will be denied in the absence of proof of a definite agreement between the parties which has been misstated in the written memorandum because of a mistake common to both contracting parties. In our opinion the evidence was legally insufficient to show a mutual mistake on Chas-[383]*383tian’s part and further the form of submission requested by Champlin was defective in that it failed to submit the basic issue of whether or not Champlin and Chastain agreed that the “plant formula” should measure the liquid hydrocarbons contained in Chastain’s gas. A definite agreement, a meeting of the minds, is basic to the remedy of reformation. Cf. Pegues v. Dilworth, 134 Tex. 169, 132 S.W.2d 582 (1939); Sun Oil Company v. Bennett, 125 Tex. 540, 84 S.W.2d 447 (1935).
The Contention of Equitable Estoppel
Petitioners contend that respondents are estopped from questioning the allocation of “plant products” which were measured by and delivered to them under the “plant formula.” In making this contention, Champlin relies primarily upon the jury’s answers to special issues Nos. 2, 3, 4 and 5. The trial court submitted numerous special issues, many of which were eviden-tiary rather than ultimate in nature.1 For discussion purposes here, we set out Special Issues Nos. 1 to 5, inclusive.
1. “Do you find from a preponderance of the evidence that the plaintiffs knew prior to the time when Chastain met John McNamara, that the allocation method used by the defendants was different from the allocation formula described in the Natural Gas Processing Agreement? Answer: No.
2. “Do you find from a preponderance of the evidence that the plaintiffs, prior to the time when Chastain met John McNamara, could have discovered by the use of ordinary care that the allocation method used by defendant was different from the allocation formula described in the Natural Gas Producing Agreement? Answer: Yes.
3. “Do you find from a preponderance of the evidence that the plaintiffs, [384]*384by acts, conducts, or silence, if any, led Champlin reasonably to believe that the plaintiffs approved of the continuation of the allocation method being used by the Champlin plant ? Answer: Yes.
4. “Do you find from a preponderance of the evidence that Champlin relied upon such acts, conduct, or silence of the plaintiffs, if any you have found in answer to the foregoing special issue? Answer: Yes.
5. “Do you find from a preponderance of the evidence that but for such acts, conduct or silence of the plaintiffs, if any you have so found, Champlin would have taken voluntary action or legal proceedings to protect itself against loss if any resulting from the use of more than one allocation method? Answer: Yes.
Champlin’s argument is that although from and after the letter of September 12, 1958, Chastain may not have had conscious knowledge that there was difference between the “contract formula” and the “plant formula”, nevertheless, Chastain by virtue of the information contained in such letter and the statements subsequently rendered to him, must be charged with notice of the divergence between the formulae in view of the holdings of the jury.
Chastain answers this argument by asserting primarily that the jury’s answers to Special Issues Nos. 2, 3, 4 and 5 are not controlling of the case. It is urged that Champlin’s letter of September 12, 1958, did not clearly disclose the situation to Chastain even when taken in connection with the statements subsequently delivered to him. It is also urged that there was no evidence to support the jury’s answers to said Issues Nos. 2, 3, 4 and 5, and that such answers were contrary to the overwhelming preponderance of the evidence.
The Court of Civil Appeals agreed with Chastain’s primary position and held as a matter of law that Champlin’s letter of September 12, 1958, which was delivered to Chastain as well as to all of the other producers furnishing gas to Champlin’s processing plant “was calculated to deceive and mislead Chastain.” Much emphasis is placed upon the statement in the letter that “Humble agrees with Champlin that this procedure (the plant formula) which has been in actual use since 1948 and adjusted slightly in 1952 is most equitable and after reviewing the entire matter Pan American expresses no 'disagreement with the procedure.” It is pointed out that Humble and Pan American would receive more credits for “plant products” under the “plant formula” than they would under the. “contract formula”. The basis of the decision of the Court of Civil Appeals is the broad maxim of equity, that he who seeks equity must come into court with clean hands; that “[t]he doctrine of estoppel is for the protection of innocent persons, and only the innocent may invoke it.” 31 C.J.S. Estoppel § 75, p. 453. Some reliance is also placed upon the jury’s finding that “Champlin failed to use ordinary care in failing to advise plaintiffs (Chastain) that the method of plant allocation that defendants (Cham-plin) were using resulted in plaintiffs being allocated less plant products than was provided for in the natural gas processing agreement.”
We do not follow this negligence argument. There was nothing careless about the notification Chastain received, even if such notice be deemed insufficient. The letter of September 12, 1958 was deliberately written. Chastain contends that it was artfully composed, designed to conceal rather than disclose. And this is essentially the basic premise of his argument.
Equitable maxims suggest avenues of investigation, but decrees are usually based upon definite and specific guide lines. This lawsuit belongs to a specific category. It is essentially an accounting suit in that it involves an account running between the processor of gas on one hand and a producer of gas on the other. Millions of [385]*385dollars have been paid out to numerous producers from month to month extending over a period of years. Many of the principles of an account stated have application here in view of the monthly statements rendered by Champlin to Chastain. Had Chastain actually and consciously realized that Champlin was operating upon an allocation basis different from that prescribed in the contract, an estoppel would have undoubtedly arisen against him, particularly after he had been requested in 1958 to make known any objections he might have to Champlin’s continuing to operate the plant upon the allocation basis which had been in force since 1948.
In re Shoemaker, 277 Pa. 424, 121 A. 510 (1923) by the Supreme Court of Pennsylvania, is closely in point here. It there appeared that the owners of adjoining lands underlaid with coal decided to conduct mining operations for their pecuniary advantage and agreed that the various tracts should be operated as a unit. The mining lease covering the tracts set forth a method of fixing the respective portions of the rents due each owner. This method was based upon an estimate of the coal underlying each of the tracts involved. However, in 1901 after receiving a report from a mining engineer that the coal in one of the veins was practically exhausted, the trustee in charge of disbursements from the proceeds of the mining operation notified all interested parties that the method of allocating royalties upon the basis of the estimated coal reserves would be discontinued and payment would thereafter be made upon the actual amount of coal produced from each tract. The trustee stated:
“I deem it advisable and really imperative to discontinue the payment of royalty on this vein on percentages as formerly, and in lieu thereof, make payments on a basis of actual mining or yield from each respective holding. As a consequence, some will receive for a time no royalty, some less, while others will receive an increase.”
The scheme of division set forth in the 1901 letter was followed for some eighteen years, yet, nevertheless, the Court of Common Pleas held that the plan of allocating royalties set forth in the lease (based upon estimated reserves) was controlling. The Supreme Court reversed, holding that notwithstanding the circumstance that the royalty allocation provisions contained in the lease were unambiguous, the eighteen years acquiescence in the division formula set forth in the 1901 letter raised an estop-pel against the royalty claimants which precluded them from questioning the trustee’s royalty allocations. The Court said:
“[T]he trustee advised all parties of the intended change (in the royalty allocation method), and that all would be paid thereafter as coal was mined under their several lots, and this was done, at the market price, without any objection for a long period of time. Some owners received prompt return for all they owned, while others were denied any. The lessors, with knowledge of the facts, permitted the substituted plan to be carried out, though it increased the present benefit to some at the expense of others, and ended in payment to a few for all the remaining coal owned, at the current rates, thus effecting, as far as they were concerned, the apparent purpose sought to be realized when the trust agreement was made. It would be inequitable to now permit a collection of a larger amount, based on the value of the unmined coal of others. If the price had fallen, instead of increasing, no recovery, in relief of those still owning, could have been had, the plan of payment having been in force with the consent of all, and those satisfied in full, or in part, should not be permitted now to repudiate the understanding.
“ ‘Where a person, with actual or constructive knowledge of the facts, induces another by his words or conduct to believe that he acquiesces in [386]*386or ratifies a transaction, or that he will offer no opposition thereto, and that other, in reliance on such belief, alters his position, such person is es-topped from repudiating the transaction to the other’s prejudice. And this is so regardless of the particular intent of the party whose acquiescence induces action.’ 21 C.J. 1216.
“ ‘But it seems that the acquiescence need not involve anything in the nature of a positive affirmation, as the rule is well recognized that when a party with full knowledge, or with sufficient notice or means of knowledge, of his rights and all the material facts, remain inactive for a considerable time or abstains from impeaching the transaction, so that the other party is induced to suppose that it is recognized, this is acquiescence, and the transaction, although originally impeachable, becomes unimpeachable.’ 10 R.C.L. 694.
“If one, knowing his rights, sees the other acting on a mistaken notion as to his, an estoppel may arise. P. & R. C. & I. Co. v. Schmidt, 254 Pa. 351, 98 Atl. 964; Lancaster v. Flowers, 208 Pa. 199, 57 Atl. 526, and authorities there cited.”
The quotations from Corpus Juris and Ruling Case Law suggest the vital issue contained in the equitable estoppel contention. The phrases, “[w]here a person, with actual or constructive knowledge of the facts” and “when a party with full knowledge, or with sufficient notice or means of knowledge" are used. See, 31 C.J.S 589, Estoppel § 114, 19 Am.Jur. 676, Estoppel, § 62. In the present case the jury has found that Chastain long prior to the time he instituted this suit could have discovered by the use of ordinary care that the allocation method used by Champlin was different from that contained in the Natural Gas Processing Agreement which he had signed. Is this finding taken in connection with the undisputed evidence — the knowledge imparted by the letter of October, 1958 — sufficient in law to impute to Chas-tain, notice of a difference between the “plant formula” and the “contract formula”, or stated another way, can it be said in the light of the jury’s finding that Chastain had sufficient means of knowledge to charge him with notice of the fact that the plant formula and the contract formula were not identical? If so, then this case would come within the rule of the Pennsylvania case which is regarded as a sound decision relating to the problem before us.
Whatever may be said as to the artfulness of Champlin’s letter to those producing to its processing plant, such letter stated in words that no one could misunderstand that (1) a question had been raised as to the language in the processing agreements (the contract formula) as compared to the actual procedure (the plant formula) used by Champlin for the allocation of plant liquids (plant products); that (2) it was desirable that the same allocation formula be applied to all producers in the area, and that (3) unless objection was made, Champlin would continue to use the “plant formula”. The letter further referred Chastain to the monthly reports designated as “Gas and Liquid Production Reports” which Chastain had in his office. These reports not only showed what and how the plant liquids were allocated to Chastain, but contained the same information for the 164 other producers, including Champlin. These reports if carefully examined would disclose the difference in the two formulae simply by comparing the reports with the contract allocation. The letter to Chastain reported to him that the procedure used in allocating plant liquids was fully reflected in the Gas and Liquid Production and Disposition Reports, complete copies of which he received monthly. The truth of this representation is borne out by the testimony of Mr. Berry Holmes, an independent public accountant of Dallas, Mr. William E. Rembert, Jr., the man in charge of Chas-tain’s accounting and who really acted as Chastain’s “righthand man”, and Mr. [387]*387Hillier, an independent public accountant with Price Waterhouse & Company, which concern was employed by Chastain to make an analysis of the same accounting statements to which the letter referred. All three testified in effect that the monthly reports made a full disclosure of the method of allocation used in the plant operation. Mr. Rembert further testified that the difference in the allocation method used at the plant and that described in the processing agreement was apparent on the face of the production and disposition reports.
However, Chastain, and his office, made no check or review of the monthly reports sent to them, although their attention was specifically directed to the reports by the September, 1958, letter. Had a check been made, many details which Chastain now says were concealed would have been disclosed. This is demonstrated by the fact that William E. Rembert, Chastain’s accountant, for the purposes of this suit, actually calculated the additional barrels of liquid which would have been allocated to Chastain by application of the allocation method set forth in the contract. In making this calculation, Rembert used the monthly reports which Chastain had in his office and demonstrated that he thoroughly understood the details of the reports and the operation of the plant allocation method.
It therefore appears that within a short time after operations commenced under the gas processing contract, Chastain had reports in his office from which he could have ascertained that the accounting rendered by Champlin was not in accordance with the terms of the contract. The letter of September 12, 1958, rather pointedly called his attention to the fact that a question had been raised as to whether or not the accounting basis in use was the one which was prescribed in the contract and he was advised that unless objection was made within a thirty day period, Champlin would continue accounting to its gas producers on the same basis that had been used in the past. Then, in March of 1961, Chas-tain had his Conversation with Castleberry and Castleberry informed him that if the contract formula were followed, he would receive an additional amount of money. Surely, had Chastain taken no action after the Castleberry interviews, he would not be in a position some years later to question the liquid hydrocarbon accounts. However, Castleberry gave Chastain no information he could not have obtained by examining the reports in his office. Conceding that Chas-tain might be excused for a failure to examine such reports prior to September 12, 1958, may it be said as a matter of law that he was also excused for a failure to examine such reports and compare the same with his contract from and after September 12, 1958, when he was told that a question as to the accounting basis had arisen and asked to make known any objection he might have to a continuation of the existing accounting method? We are of the opinion that it may not. We think there was some evidence from which a jury could conclude that the means of knowledge were available to a reasonably careful person and hence knowledge of Champlin’s use of an allocation formula different from that set out in the contract should be imputed to Chastain. This case is one involving an account, and generally in the business world when an account is presented, the opposite party is under some duty to object thereto if the same be incorrect or inaccurate. Especially is this true when an explicit request for objection is made if the recipient be not satisfied with the accuracy of the account. The underlying principle is that of equitable estoppel or estoppel in pais. This doctrine was recognized by this Court in the case of Love v. Barber, 17 Tex. 312 (1856) in which it was said:
“The doctrine of an estoppel, not of record or under seal, called an estoppel in pais, was left for a considerable time in a state of perplexity and uncertainty. It is, however, believed that [388]*388various adjudications have settled the doctrine on principles easy to be understood. Nowhere has it been more concisely and clearly laid down than by Lord Denman in the case of Pickard v. Sears, Eng. C. L. vol. 33, p. 117, [112 Eng.Rep. 179]. He says ‘that the rule of law is clear, that when one, by his words or conduct, wilfully causes another to believe the existence of a certain state of things, and induces him to act on that belief, so as to alter his own previous position, the former is concluded from averring, against the latter, a different state of things, as existing at the same time; and the plaintiff in this case might have parted with his interest in the property by a verbal gift or sale, without any of these formalities that throw technical obstacles in the way of legal evidence.' (See Walker’s Adm’r v. Livingston et al., 3 Tex. 93.) This rule is much to be admired for its simplicity, its briefness, and it yet being expressive of the whole doctrine on the question.”
In the case of Gregg v. Wells, 10 Ad. & E. 97, 113 Eng.Rep. 35 (1839), Lord Den-man referred to his former opinion and said:
“Pickard v. Sears (6 A. & E. 469), was in my mind at the time of the trial, and the principle in that case may be stated even more broadly than it is there laid down. A party, who negligently or culpably stands by and allows another to contract on the faith and understanding of a fact which he can contradict, cannot afterwards dispute that fact in an action against the person whom he has himself assisted in deceiving.”
It seems clear that under certain circumstances, one having the means of knowledge may be held to the same standard of responsibility as one possessing conscious knowledge. In Dimond v. Manheim, 61 Minn. 178, 63 N.W. 495 (1895), the Court after citing and quoting from Pomeroy, Equity Jurisprudence, set forth the following rules:
“The authorities are, however, substantially all agreed upon the following general propositions: First, to create an estoppel, the conduct of the party need not consist of affirmative acts or words. It may consist of silence or a negative omission to act when it was his duty to speak or act. Second, it is not necessary that the facts must be actually known to a party estopped. It is enough if the circumstances are such that a knowledge of the truth is necessarily imputed to him. Third, it is not necessary that the conduct be done with a fraudulent intention to deceive, or with an actual intention that such conduct will be acted upon by the other party. It is enough that the conduct was done under such circumstances that he should have known that it was both natural and probable that it would be so acted upon.”
It has been determined by Texas authority that imputed actual notice carries with it the same legal consequences as conscious knowledge. In Hexter v. Pratt, 10 S.W.2d 692, (Tex.Com.App.1928) it was said:
“Notice in law is of two kinds— actual and constructive. * * * In common parlance ‘actual notice’ generally consists in express information of a fact, but in law the term is more comprehensive. In law whatever fairly puts a person on inquiry is sufficient notice, where the means of knowledge are at hand, which if pursued by the proper inquiry the full truth might have been ascertained. Means of knowledge with the duty of using them are in equity equivalent to knowledge itself. * * * So that, in legal parlance, actual knowledge embraces those things of which the one sought to be charged has express information, and likewise those things which a reasonably diligent inquiry and exercise of the means of [389]*389information at hand would have disclosed.”
The Hexter case was cited with approval by this Court in Woodward v. Ortiz, 150 Tex. 75, 237 S.W.2d 286 (1951), wherein it was said:
“It may well be, however, that the tax attorney and the County were charged with actual notice of the judgment even though they had no express knowledge thereof. Actual notice ‘embraces those things of which the one sought to be charged has express information, and likewise those things which a reasonably diligent inquiry and exercise of the means of information at hand would have disclosed.’ ”
The theory that Champlin relied on Chastain’s silence after receiving the letter of September 12, 1958, has support in the fact that Champlin told • Chastain that it would rely upon his silence and continue accounting for “plant products” in accordance with the “plant formula” then in use. Champlin thereafter distributed millions of dollars representing the proceeds from the liquids allocated to the various producing wells in accordance with the “plant formula”. By so doing, it continued to allocate less liquid products to some wells and more liquid products to other wells than it would have done under the “contract formula”. Since Champlin had contracts with all of the other 164 producers which contained the same allocation formula as that contained in Chastain’s processing contract, it would follow that if Champlin were compelled to pay Chastain the difference between the “plant products” which would have been allocated to him under the “contract formula” and those actually delivered under the “plant formula”, then Champlin would have been able to recoup (in part, at least) by requiring a reallocation of products as to all other producers in conformity with the literal provisions of the formula set out in Section 8 of the gas processing agreement. If Champlin relied upon Chas-tain’s silence in continuing to operate under the “plant formula”, then it lost its opportunity to reallocate the “plant products” under the “contract formula” and thus minimize its losses. There is some evidence supporting the jury’s findings to Issues Nos. 2, 3, 4 and 5, and those findings are sufficient in law to support an estoppel precluding Chastain from now questioning his account with Champlin on the ground that the allocation of liquid hydrocarbons should have been made in accordance with the “contract formula” rather than the “plant formula”. This requires a reversal of the judgments of the Courts below.
Champlin’s Complaint as to the Exclusion of Evidence
We need not further lengthen this opinion by an extended discussion of these complaints. The evidence excluded consisted for the most part of charts and diagrams designed to summarize and perhaps emphasize the testimony of Champlin’s witnesses. The admission of evidence of this kind generally lies within the discretion of the trial judge. The exclusion of the proffered evidence in this case did not constitute a reversible error, nor can it be said that such evidence was vital in determining the “no evidence” points in this Court, nor the “weight and preponderance” points in the Court of Civil Appeals.
Chastain’s Conditional Application
In a conditional application for writ of error, Chastain contends that the Court of Civil Appeals erred in sustaining Champlin’s contention with reference to the four-year statute of limitations and modifying the trial court’s judgment because of such holding. The intermediate court’s holding was that certain payments made by Champlin to Chastain were designated as being for gas products sold by Champlin for Chastain’s account for specific periods of time and that accordingly the general rule that payments on an account should be credited to first maturing items thereof was [390]*390not wholly applicable to the account involved. For a statement of the rule, see Curry v. O’Daniel, 102 S.W.2d 481 (Tex.Civ.App.1937, wr. ref.). We find no error in the Court of Civil Appeals’ holding that the specially designated payments operated to vary the general rule and we are further of the opinion that there is evidence to support the finding that certain payments were made for designated months. Of course, should there be another trial, the evidence relating to payments for specified months may be different or more complete than that contained in the record now before us.
Chastain also contends that he is entitled to attorney’s fees under the provisions of Article 2226, Vernon’s Ann.Tex. Civ. Stats., in that under the contract he furnished materials to Champlin. The contract obligated Chastain to deliver or cause to be delivered to Champlin’s processing plant a volume of natural gas which was to be processed for the recovery of various hydrocarbons called “plant products” and that a portion of such products would be sold by Champlin to third persons for Chas-tain’s account and the products remaining would be retained by Champlin as a processing fee. The gas delivered to Champlin for processing under this agreement is not within the meaning of “material furnished” as that term is used in Article 2226, and the Court of Civil Appeals was correct in so holding.
Chastain’s Contention that the Jury’s Answers to Special Issues Nos. 2,3, 4 and 5 are Against the Overwhelming Preponderance of the Evidence
Our jurisdiction extends to questions of law only. Article S, § 3, Texas Constitution, Vernon’s Ann.St. Questions of whether or not a jury finding is against the overwhelming preponderance of the evidence lies within the exclusive jurisdiction of the Court of Civil Appeals. Article 5, § 6, Texas Constitution; King v. King, 150 Tex. 662, 244 S.W.2d 660 (1951); Calvert, “ ‘No Evidence’ and ‘Insufficient Evidence’ Points of Error”; 38 Texas L.Rev. 361 (1960); Garwood, “The Question of Insufficient Evidence on Appeal”; 30 Texas L. Rev. 803 (1952). Chastain has preserved his points asserting that the jury’s findings here are against the weight and preponderance of the evidence by complying with Rule 324, Texas Rules of Civil Procedure.
As pointed out in the forepart of this opinion, Chastain contended in the Court of Civil Appeals that as a legal proposition, the jury’s answers to Special Issues Nos. 2, 3, 4 and 5 were immaterial in that it appeared as a matter of law that Champ-lin could not claim an estoppel because of its own conduct in the premises. 379 S.W. 2d 938, 1. c. 942. We disagree with that holding and have held that there was some evidence supporting the jury’s findings to Special Issues Nos. 2, 3, 4 and 5. The discussion in this opinion has reference to legal questions only as we have no fact jurisdiction and for that reason we have called attention to those portions of Champ-lin’s letter of September 12,1958 which constituted some evidence supporting the jury’s findings upon which an estoppel is predicated, — such as, notice that a question had arisen as to the allocation formula, the desirability of applying the same formula to all producers and the request for notification if further distributions in accordance with the “plant formula” would not be satisfactory. The overwhelming preponderance question is another matter. It relates to the power to grant a new trial, which power is essentially the same whether exercised by a Court of Civil Appeals or a trial court. It is a “fact” and not a “law” jurisdiction. Contrary to the historic practices of most Anglo-American jurisdictions, juries are used to determine equitable rights and claims in Texas. A jury verdict is not merely advisory although it is to be tested by both the “no evidence” and “the overwhelming preponderance” rules. This is made abundantly clear by this Court’s decision in Sanders v. Harder, 148 Tex. 593, 227 S.W.2d 206 (1950).
[391]*391The Court of Civil Appeals did not discuss and obviously did not pass upon the question of whether the jury’s answers were against the overwhelming preponderance of the evidence. The rule of Barker v. Coastal Builders, 153 Tex. 540, 271 S.W.2d 798 (1954), stated on rehearing, is not applicable to this case. It is necessary that the cause be remanded to the Court of Civil Appeals to pass upon the weight and preponderance questions.
Conclusion
For the reasons herein stated, the judgments of the trial court and the Court of Civil Appeals are reversed and this cause remanded to the latter Court for further proceedings in keeping with this opinion.
CALVERT, C. J., and GRIFFIN, WALKER and POPE, JJ., dissenting.