"Mistake is some unintentional act, or omission, or error, arising from ignorance, surprise, imposition, or misplaced confidence.""

Another definition of mistake which has been given is as follows:

"Mistake may be said to exist, in a legal sense, where a person, acting upon some erroneous conviction, either of law or of fact, executes an instrument, or does an act, which, but for that erroneous conviction, he would not have executed or done." 2

SECTION 37. CLASSIFICATION OF MISTAKE.

Mistake is divided into

(a) Mistake of law, and

(b) Mistake of fact.

Equity will, under proper conditions, relieve against mistakes of the latter class, but not against those of the former.

SECTION 38. MISTAKES OF FACT.

Mistakes of fact may consist either of mistakes by the parties to the contract as to some matter which goes to the essence of the contract, or it may be the mistake of a third person who reduces the contract to writing.

A mistake of the parties to the contract, to be Story's Equity Jurisprudence. Eaton on Equity Jurisprudence.

relievable, must be mutual. An exception is found in cases where there is mistake on one side and fraud on the other. This exception, perhaps, would rather come under the head of fraud.

The necessity for the mutuality of the mistake was asserted by the Court in the case of Dinian vs. The Providence W. & B. R. R. Co., as follows:

"A court of equity has no power to alter or reform an agreement made between parties, since this would be in truth a power to contract for them; but merely to correct the writing executed as evidence of the agreement, so as to make it express what the parties actually agreed to. It follows that the mistake which it may correct in such a writing must be, as it is usually expressed, the mistake of both parties to it; that is, such a mistake in the draughting of the writing as makes it convey the intent or meaning of neither party to the contract. If the court were to reform the writing to make it accord with the intent of one party only to the agreement, who averred and proved that he signed it, as it was written, by mistake, when it exactly expressed the agreement as understood by the other party, the writing, when so altered, would be just as far from expressing the agreement of the parties as it was before; and the court would have been engaged in the singular office, for a court of equity, of doing right to one party at the expense of a precisely equal wrong to the other."

SECTION 39. MISTAKE AS TO EXISTENCE OF SUBJECT MATTER OF CONTRACT.

When the subject matter of the contract was not in existence at the time of the making of the 5 R. I., 130.

contract, there is a mutual mistake against which equity will relieve. This rule also applies in the case of contracts for services, where, on account of facts unknown to either party at the time of the making of the contract, the performance of the services was unnecessary or impossible. This doctrine was laid down by the Supreme Court of the United States in the case of Allen vs. Hammond, where a contract had been made by which Allen was to be allowed a large commission upon the allowance in favor of Hammond of a certain claim by the Portuguese government, which claim, unknown to the parties, had been allowed eight days prior to the making of the contract. The decision in this case was in part as follows: "No one can read the contract without being struck with the large sum that Hammond is willing to pay on the contingency of recovering his claim. Allen was to receive as a compensation for his services, a sum little below the one-third of the amount recovered. This shows, in the strongest point of view, that Hammond could have entertained but a remote prospect of realizing his claim; and, indeed, it would seem, when the circumstances of the case are considered, that he could have had little or no ground to hope for success.

"His vessel and cargo had been condemned; the Portuguese Government was in an unsettled state, and its finances in the greatest confusion and embarrassment.

"In his vessel and cargo Hammond appears to have lost his entire property; and this very naturally threw him into despondence, and induced him to agree to pay nearly one-third of his demand to an • 11 Peters, 63.

agent who might, by possibility, recover it. He, no doubt, supposed that by interesting his agent so deeply in the claim, he would secure his sympathies and his utmost exertions. And the prospect was, if the claim or any part of it should be obtained, it would be the work of time, and of great effort.

"Allen is not chargeable with fraud in entering into the contract, or in using the most persevering efforts to get possession of the installment paid.

"That the contract was entered into by both parties under a mistake is unquestionable. Neither of them knew that the Portuguese Government had allowed the claim. Can a court of equity enforce such a contract? Can it refuse to cancel it? That the agreement was without consideration is clear. Services long and arduous were contemplated as probable, by both parties, at the time the contract was executed. But the object of pursuit was already attained. No services were required under the contract, and for those which Allen had rendered to Hammond prior to it regular charges seem to have been made.

"It is true the amount of services required by the agent was uncertain. He took upon himself this contingency, and had not the claim been allowed by the Portuguese Government until after the contract, he would have been entitled to his commissions, however small his agency might have been in producing the result. This, it may be supposed, was a contingency within the contemplation of the parties at the time of the contract; so that, unconnected with other circumstances, the smallness of the service rendered could have constituted no ground on which to set aside the contract.

"But no one can for a moment believe that Ham