The obligation resulting in various cases from the receipt of a benefit conferred in misre-liance upon a contract which turns out to be invalid or unenforceable has been considered in the preceding chapters. Upon the same underlying principle, and with the same limitations, the receipt of a benefit conferred under a mistake as to the terms of a valid and enforceable contract,1 or as to the existence of a fact affecting the obligation to perform a contract,2 or as overpaid him); Pearson v. Lord, 1809, 6 Mass. 81, (payment by underwriter in ignorance either that defendant had insured more than his own interest in ship and cargo, or that insurance was restricted, by terms of policy, to interest of defendant); Garland v. Salem Bank, 1812, 9 Mass. 408; 6 Am. Dec. 86; Talbot v. Nat. Bank of Commonwealth, 1880, 128 Mass. 67; 37 Am. Rep. 302, (payment of note by indorser under mistaken belief that it had been dishonored); Merchants' Ins. Co. v. Abbott, 1881, 131 Mass. 397, (payment of insurance in ignorance of facts avoiding policy); Nollman v. Evenson, 1895, 5 N. D. 344; 65 N. W. 686, (payment on contract for plastering under mistaken belief that work had been properly done); Phetteplace v. Bucklin, 1893, 18 R. I. 297; 27 Atl. 211, (payment of lapsed legacy by surety of executor); Guild v. Baldridge, 1852, 2 Swan (32 Tenn.) 294, (plaintiff twice paid price of logs purchased by him); Turner Falls Lumber Co. v. Burns, 1899, 71 Vt. 354; 45 Atl. 896, (payment for timber purchased from defendant under mistake as to boundary).

1 Pearson v. Lord, 1809, 6 Mass. 81, (payment by underwriter in ignorance either that defendant had insured more than his own interest in ship and cargo, or that insurance was restricted, by terms of policy, to interest of defendant).

2 Bize v. Dickason, 1786, 1 Term R. 285, (overpayment by creditor of bankrupt to assignee in bankruptcy, because of plaintiff's ignorance that he could set off claim against bankrupt); Irving v. Richardson, 1831, 2 Barn. & Ad. 193, (overpayment on policy of marine insurance in ignorance of fact that there was other insurance); Kelly v. Solari, 1841, 9Mees. & Wels. 54, (payment of lapsed insurance policy); Mills v. The Alderbury Union, 1849, 3 Exch. 590, (payment by surety on bond under mistaken belief that the principal had defaulted); Ray & Thornton v. Bank of Kentucky, 1843, 3 B. Mon. (42 Ky.) 510; 39 Am. Dec. 479, (plaintiff ignorant that he was exonerated from payment of bill because of defendant's failure to present to acceptor on time); Baltimore, etc., R. Co. v. Faunce, 1847, 6 Gill (Md.) 68; 46 Am. Dec. 655, (plaintiff's agent in settling with defendant overlooked a credit and so to the amount of money or property called for by a contract,1 raises an obligation to make restitution.

1 Money: Townsend v. Crowdy, 1860, 8 C. B. N. S. 477, (overpayment on purchase of interest in partnership under mistake as to amount of profits); Newall v. Tomlinson, 1871, L. R. 6 C. P. 405, (overpayment for goods purchased, as result of error in computing weight); First Nat. Bank of Omaha v. Mastin Bank, 1880, 2 McCrary (U. S. C. C.) 438; 48 Fed. 433, (overpayment under mistake as to state of account between two banks); Griffith v. Johnson's Admr. 1837, 2 Harr. (Del.) 177, (overpayment on bond); Devine v. Edwards, 1881, 101 111. 138, (overpayment for milk due to mistake as to capacity of milk cans); Worley v. Moore, 1884, 97 Ind. 15, (overpayment on notes due to miscalculation of interest); Stotsenburg v. Fordice, 1895, 142 Ind. 490; 41 N. E. 313, 810, (overpayment of debt; interest computed at 8 per cent instead of 6 per cent); Major v. Tardos, 1859, 14 La. Ann. 10 (overpayment of debt by reason of compounding interest); Goddard v. Putnam, 1843, 22 Me. 363, (overpayment of note under mistaken impression that it bore interest from date); Baltimore, etc., R. Co. v. Faunce, 1847, 6 Gill (Md.) 68; 46 Am. Dec. 655, (plaintiff's agent in settling with defendant overlooked a credit and so overpaid him); Stuart v. Sears, 1875, 119 Mass. 143 (overpayment in settlement of account under mistake as to previous payments); Trecy v. Jefts, 1889, 149 Mass. 211; 21 N. E. 360, (overpayment under mistake as to amount of debt); Lane v. Pere Marquette Boom Co., 1886, 62 Mich. 63; 28 N. W. 786, (overpayment for driving logs as a result of mistake in woods scale); City of Duluth v. McDonnell, 1895, 61 Minn. 288; 63 N. W. 727, (overpayment of contractor resulting from mistake in measurement of work done); Billings v. McCoy Brothers, 1876, 5 Neb. 187, (overpayment for cattle due to mistake in weighing); Wheadon v. Olds, 1838, 20 Wend. (N. Y.) 174, (overpayment for oats purchased, a result of error in estimating quantity); George v. Tallman, 1871, 5 Lans. (N. Y. Sup. Ct.)

The fact that in a given case the mistake is as to the requirement of a contract with a third person instead of with the defendant is immaterial, if it is a mistake affecting the duty, and not merely the policy, of doing that which benefits the defendant (ante, Sec. 19). This was not appreciated, apparently, in the Vermont case of Johnson v. Boston and Maine Railroad Company,1 for it was there held that the plaintiff, who made certain transfers of mail under the mistaken belief, shared by the defendant, that his contract with the government required him so to do, whereas in fact the duty of making the transfers rested upon the defendant, could recover nothing for his services. The Supreme Court of Michigan, however, in a similar case permitted a recovery.2