Opinion of the Court a dispute as to some of these items which must be left for the courts to determine or to be settled otherwise. This agreement was made for the purposes of the settlement alone. The whole tenor of plaintiff's proposition indicated that the plaintiff was willing to make concessions in order to obtain a "quick settlement," and the settlement only related to the operating contract between the plaintiff and defendant. The plaintiff can not now go further and claim that not only the amount due under the operating contract but other matters were settled at the same time, such as the rate to be paid for the telegrams. We find that no estoppel was created. In the remaining cause of action the plaintiff seeks to recover on the ground of mutual mistake, if (according to the language of the petition) the settlement did not imply a warranty entitling the plaintiff to recover the commercial rate. It is quite possible that at the time the proposition of settlement was made on behalf of the plaintiff it was thought by the president of plaintiff that if the accounts should "be passed from one to the other at their face value" it would even matters between the parties regardless of how the dispute as to the rate was finally determined, whereas it is now quite evident that such is not the case. But a mistake of this character, even if it were mutual, is not such a mistake that the courts will grant relief against it. It is a mistake of law, not of fact; and the same is true even if the plaintiff's officers mistakenly believed that the provision above set out established the validity of the accounts in question at the commercial rate. Beyond this it should be said that in either case there is no evidence that the mistake, if any, was mutual. On the contrary so far as the evidence goes, it tends to show that, on behalf of the Government, it was insisted from first to last that it was entitled to the special rate. There remains for disposition the counterclaim of the defendant. We are unable to see why the same rules would not apply. The money that was paid as tolls on these telegrams while the Government was in control eventually went Reporter's Statement of the Case into the Treasury of the plaintiff, and it was paid with the express understanding that if it should subsequently be found that the Government rate was applicable thereto the overpayment should be refunded. The counterclaim should therefore be sustained. The Thompson-Starrett Company paid for these telegrams, as agents for the Government, $1,738.79. At Government rates the charge would have been $695.52. The defendant, therefore, is entitled to recover the difference, which is $1,043.27, and in making up final judgment it is entitled to have this sum credited on the amount admitted to be due on the telegrams which were not paid for, which is $44,147.48, leaving a net amount due from the defendant to the plaintiff of $43,104.21, for which judgment will be entered in favor of the plaintiff. Moss, Judge; GRAHAM, Judge; and BooтH, Chief Justice, concur. FEATHER RIVER LUMBER CO. v. THE UNITED STATES1 [No. F-68] On the Proofs Refund of income tax; requirement of claim; prerequisite to suit.— A claim for refund of income tax submitted to the Commissioner of Internal Revenue must, under the revenue laws and regulations, show the errors complained of, before the taxpayer can maintain suit, and a claim for refund of 1918 taxes solely on account of depreciation and depletion, does not have the necessary particularity for a claim for refund of 1918 taxes on account of a net loss in the year 1919. The Reporter's statement of the case: Mr. George E. H. Goodner for the plaintiff. Matthews & Trimble were on the brief. Mr. Frederick W. Dewart, with whom was Mr. Assistant Attorney General Herman J. Galloway, for the defendant. Mr. Lisle A. Smith was on the brief. 1 Certiorari denied. Reporter's Statement of the Case Decided May 28, 1928. Motion for new trial overruled October 8, 1928. The court made special findings of fact, as follows: I. Plaintiff is a corporation organized and existing under the laws of the State of Colorado and having its principal office at Denver, Colo. II. Plaintiff was incorporated on January 25, 1905, and ever since said date has been engaged in the business of cutting timber and sawing the logs into lumber and marketing same. III. Plaintiff filed a timely income-tax return for the calendar year 1918 and reported therein taxable net income of $27,066.90 and a total tax liability thereon of $3.008.03, which tax was duly assessed by the Commissioner of Internal Revenue and paid by plaintiff. IV. Upon audit of plaintiff's 1918 return the commissioner found the taxable net income to be $26,016.22 and the tax liability to be $2,881.95. Thereafter the commissioner caused a certificate of overassessment, No. 625432. to be issued showing an overassessment for 1918 of $126.08. Exhibit A attached to plaintiff's petition and made a part of this finding by reference, is a correct copy of said certificate of overassessment, which said certificate was received by plaintiff, accompanied by a Treasury warrant for $126.08, on or about April 15, 1924. V. On or about the 15th day of March, 1920, plaintiff filed its income-tax and excess-profits tax return for the year 1919, a correct copy of which return is annexed to plaintiff's petition as Exhibit B, and made a part of this finding by reference. VI. On March 14, 1924, plaintiff filed with the collector of internal revenue for the district of Colorado a refund. claim prepared on Treasury Department Form 843, demanding refund of the total tax paid for 1918. Exhibit C attached to plaintiff's petition is a correct copy of said claim, and made a part of this finding by reference. More than six months elapsed between the filing of said claim and the filing of the petition herein. No other claim for refund of Opinion of the Court any part of the taxes paid by plaintiff for the year 1918 was filed. VII. The commissioner arrived at the taxable net income for 1918 of $26,016.22 and the total tax liability of $2,881.95 without giving any deduction for a net loss in the year 1919 under section 204 of the revenue act of 1918 (40 Stat. 1060). VIII. The total income tax paid to the collector of internal revenue by plaintiff for 1918 was $3,008.03, of which $126.08 has been refunded as aforesaid. The balance of said payment, to wit, $2,881.95, is still retained by the United States, and the Commissioner of Internal Revenue refuses to refund any part of same. The court decided that plaintiff was not entitled to recover. Moss, Judge, delivered the opinion of the court: On June 16, 1919, plaintiff filed its income-tax return for the year 1918 and paid the tax shown to be due, amounting to $3,008.03. On the 14th day of March, 1924, plaintiff filed a claim for the refund of said sum, setting forth the grounds as follows: "Taxpayer's 1918 return has not yet been audited by the commissioner at Washington, D. C., but it appears from agreements reached in conference with representatives of the Bureau of Internal Revenue relative to depreciation and depletion that its 1918 taxes have been overpaid and that a refund is due. This claim is filed in order to protect taxpayer's rights under sections 252 and 1324 of the revenue act of 1921, because the right to claim refunds for 1918 will soon be barred by the statute of limitations." The claim for refund was allowed to the extent of $126.08, which was paid. In March, 1920, plaintiff filed its incometax return for the year 1919, which showed no taxable income, but a net loss of $4,891.15, as alleged by plaintiff; $3,331.15, as computed by defendant. On May 13, 1925, plaintiff, in a letter to the Commissioner of Internal Revenue, called attention to the fact that in arriving at the taxable income for 1918 the commissioner had not deducted the net loss for 1919, and requested a recomputation of Opinion of the Court plaintiff's tax liability and a further refund of $586.94. Upon the refusal of the commissioner to grant plaintiff's request plaintiff instituted this action to recover said sum. No claim for refund was ever filed by plaintiff other than the claim hereinabove set forth. The transactions out of which the claim sued on arose had transpired prior to the filing in 1924 of the claim for refund, and there was no mention of a claim on account of net loss in 1919. The claim merely stated that agreements had been reached by the taxpayer with the Government relative to depreciation and depletion, that its 1918 taxes had been overpaid, and that a refund was due. This claim, referring only to the question of depreciation and depletion, was duly considered and in part allowed. The first mention of the claim which constitutes the basis of this action was in the letter of May 13, 1925. The purpose of requiring claims for refund as a condition precedent to the institution of an action to recover for taxes illegally or erroneously collected was to afford an opportunity for the bureau officials to correct errors arising through their own mistakes. Not until the Commissioner of Internal Revenue has been presented with a claim bringing to his attention the errors complained of, and has rejected same, or has allowed six months to elapse without taking action thereon, can the taxpayer invoke the aid of the courts. The mere showing of a net loss for the year 1919 is not sufficient. Plaintiff should have presented a claim for refund, stating its grounds therefor. There is no legal relation between the claim filed in 1924, as a claim for refund, and the claim which constitutes the basis of this action. While it has been held that the form of the claim for refund is not essential, there has been no deviation from the wellestablished rule that the aggrieved taxpayer must assert his right to a refund by an application to the commissioner containing the grounds upon which he relies for such recovery before he will be permitted to bring an action for same. See Rock Island, Arkansas & Louisiana Railroad Company v. United States, 254 U. S. 141, and cases cited therein. The question involved in this case presents an apt example for the application of the somewhat epigrammatic language of |