This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
12Naylor v. Winch 1 Sim & Stu. 555.
"If a Party, acting in ignorance of a plain and settled principle of Law, is induced to give up a portion of his indisputable Property to another under the name of Compromise, a Court of Equity will relieve him from the effect of his mistake. But where a doubtful Question arises, such as this Question of Construction, upon the Will of the Testator, it is extremely reasonable that Parties should terminate their differences by dividing the stake between them, in the proportions which may be agreed upon." Naylor v. Winch, 1 Sim. & Stu. 555.
13 Leonard v. Leonard, 2 Ball & B. 171.
14 Trigg v. Read, 24 Tenn. (5 Humph.) 520, 42 Am. Dec. 447.
15United States. Bank v. Daniel, 37 U. S. (12 Pet.) 32, 0 L. ed. 080; Ham-blin v. Bishop, 41 Fed. 74; Kiefer Oil & Gas Co. v. McDougal, 220 Fed. 033, 144 C. C. A. 215, Ann. Cas. 1016D, 343; Upson Nut Co. v. American Shipbuilding Co., 251 Fed. 707.
Alabama. Craft v. Moon, - Ala. - , 75 So. 302.
California. Gardner v. Watson, 170 Cal. 570, 150 Pac. 004.
Colorado. Coffee v. Emigh, 15 Colo. 184, 10 L.R. A. 125, 25 Pac. 83.
Illinois. McDonald v. Minnick, 147 111. 651, 35 N. E. 367.
Iowa. German Savings Bank v. Gen-eser, 110 la. 110, SO N. W. 201; Bach v. Interurban Ry. Co., - la. - , 171 N. W. 723.
Kentucky. Hartsfield v. Wray, 181 Ky. 836, 205 S. W. 965.
Maryland. Beam, Prince de v. Win-ana, 111 Md. 434, 74 Atl. 626.
Massachusetts. Toole v. Crafts, 193 Mass. 110, 118 Am. St Rep. 455, 78 N. E. 775.
Missouri. Kleimann v. Gieselmann, 114 Mo. 437, 35 Am. St. Rep. 761, 21 S. W. 706; Clark v. Carter, 234 Mo. 00, 136 S. W. 310. (Obiter, as to mistake was one of mixed law and fact.)
Oklahoma. Palmer v. Cully, 52 Okla. 454, 153 Pac. 154.
Pennsylvania. Clark v. Lehigh & Wilkes-Barre Coal Co., 250 Pa. St. 304, 05. Atl. 462.
South Carolina. Kirkland v. Mose-ley, - S. Car. - , 06 S. E. 608.
Tennessee. Ruohs v. Bank, 94 Tenn. 37, 28 S. W. 303.
A contract can not be avoided on the ground that it is entered into under a mistake as to the construction of another contract,18 or of a will.17 A conveyance can not be avoided on the ground that the grantor believed that he could revoke it as if it were a will.18 A devised realty to B in fee and B thought that she had a fee, not knowing that A could not deprive his minor children of their home-stead. Under this mistake of law, B borrowed money of C to pay off a mortgage on such realty held by X. C, finding that his mortgage was inferior to the homestead rights of A's minor children, sued to be subrogated to X's mortgage. This relief was refused.19 If A executes and delivers his promissory note to B, which recites on its face that it is executed in consideration of credit extended by X to B for a threshing machine, the fact that A believed that he could show an oral agreement that such note should be void unless his crop matured and unless B threshed such crop, is not such mistake of law as will enable A to avoid such note in the hands of X.20 A surety who had been released from liability on the original note, and not knowing that by law he is released, signs a new note for an extension of time, is liable thereon.21 If A makes a contract with full knowledge of its terms under an erroneous belief that it does not bind him,22 as where a married woman signs a note with her husband, believing that it does not bind her personally, but only her interest in land,23 such contract can not be avoided, since such mistake is not mutual; and such party can not have relief. So if A takes a conveyance from her husband B without covenants of warranty under a mistaken belief that A and B are tenancies by entireties,24 or if A agreed to and did convey to a railroad a right of way across his farm, not knowing that it would prevent him from recovering damages for injury to the rest of his farm,25 no relief can be had. A telegraph company which has agreed to pay a certain rental to a turnpike company for a right to erect telegraph poles along the side of the turnpike, believing that such telegraph company has no right to erect such poles in the absence of a contract therefor, can not avoid such lease, although by statute such right could have been exercised without making compensation.26 A compromise of a dispute as to legal rights can not be avoided because the parties were mistaken as to such rights.27 A contract to pay one who intended to contest a will for waiving such action can not be avoided, even if made under a mistake as to the legal rights of the parties, the parties knowing all the material facts.28 If A with full knowledge of the facts releases a mortgage in the belief that his deed is prior to an unrecorded deed to X because A had his deed recorded first, relief will not be given.29
Wisconsin. Kyes v. Furniture Co., 92 Wis. 32, 65 N. W. 735.
If the mistake of law is not mutual, relief will not be given. Bach v. In-terurban Ry. Co., - la. - , 171 N. W. 723.
16 Upson Nut Co. v. American Shipbuilding Co., 251 Fed. 707; Hartsfield v. Wray, 181 Ky. 836, 205 S. W. 965.
17 Kirkland v. Moseley, - S. Car. - , 96 S. E. 608.
18 Craft v. Moon, - Ala. - , 75 So. 302.
19Kleimann v. Gieselmann, 114 Mo. 437, 35 Am. St. Rep. 761, 21 S. W. 796.
20 Northwest Thresher Co. v. Mc-Ninch, 42 Okla. 155, 140 Pac. 1170.
21 Churchill v. Bradley, 58 Vt. 403, 56 Am. Rep. 563, 5 Atl. 189; see also, Toole v. Crafts, 193 Mass. 110, 118 Am. St. Rep. 455, 78 N. E. 775.
22 Milks v. Milks, 129 Mich. 164, 88 N. W. 402; McDaniels v. Bank, 29 Vt. 230, 70 Am. Dec. 406.
23 Grant v. Isett, 81 Kan. 246, 105 Pac. 1021.
24 Hancock v. Wiggins, 28 Ind. App. 449, 63 N. E. 242.
Under statutes which are in force in some states which provide for giving relief in case of mistake, and which divide mistakes into mistakes of law and mistakes of fact, a contract which is entered into by the parties under a mutual mistake of law can not be enforced.30