MISTAKE (ante), in law, is defined by Story as some unintentional act, omission, or error, arising from ignorance, surprise, imposition, or misplaced confidence. In courts of equity, as of law, the maxim applies, Ignorantia facti excusat; ignorantly juris non. excasat—ignorance of the fact, not of the law, excuses. Thus where one word has by clerical mistake been substituted for another, equity will remedy the mistake; but where the parties have knowingly used a certain form of language believing that its legal effect is different from what it is in reality, they have no such remedy. If the parties be ignorant as regards a fact and aware of their ignorance, yet intend to risk the result, or, knowing the facts, intend to compromise both the law and the facts, then courts will not regard the fact that one party profited less by the contract than he had expected. Where an estate was supposed by both vendor and vendee to belong to the vendor under the law of real property, and was sold in that belief, the court, notwithstanding that the mistake seemed to be one of law, ordered the purchase-money to be refunded. A mistake as to the law of a foreign country is considered to be of fact and not of law, as public policy does not make it necessary that a citizen should be acquainted with the laws of other countries than his own. A trifling or immaterial mistake will not be regarded as ground for disturbing a written agreement. Specific performance will not be enforced when it is clear that the defendant through a mistake not resulting from mere carelessness has entered into a contract materially different from what he had intended. The instrument or contract may be ordered to be re-executed, or may be
rescinded altogether. Titus where a solicitor, iu a conveyance, inserted double the sum intended as purchase-money, he was compelled to re-execute the deed. An award of arbitrators based on a mistake of fact will be rescinded by a court; and even when based on a mistake in law, if the questions of law were not especially referred to them. An important exception to the rule that mistake of law does not excuse exists in those cases where the defendant has voluntarily entered into a promise to perform some act, such as paying a note or accepting a bill of exchange, because he supposes himself legally hound to do so, the fact being that he is not. That is to say, no mere waiver of a legal defense, ignorantly made, will compromise the rights of the maker. Often an instrument may be so construed by the court as to carry out the intentions of the parties, but in such 'case the construction must be supported by the instrument itself and not by external evidence; thus where there is a deed of certain land, it is allowable to explain what is meant by the description of boundaries or the relative ownership of several vendees; but if it be alleged that one piece of property has been mistakenly described in place of another, the deed cannot be rectified by mere construction of a court of law, but special action must be had in equity. Where there is any element of fraud or surprise involved, or where the case is one connected with trusts, equity will go very far in cor recting the results of mistakes.