The opinion of the Court was delivered by

The exception to admitting the evidence was not urged here. In the country from which our ancestors came, and from which we took the substratum of our jurisprudence, it was once the law, and to a certain extent is yet, that a deed or writing under seal proved a consideration; and nothing could be averred against this. This in a court of law; but after a judgment in a court of law, the defendant could go to the other end of Westminster Hall, and on making out a case of fraud, want of consideration, &c., could obtain a perpetual injunction against any execution of the judgment at law; or if the recovery was of land in ejectment, he might be quieted in the possession, and compel the plaintiff to deliver up his deed to be cancelled. -The system *264and principles of the etjuity courts are very complete. Fraud in both courts, if by their practice "it can be reached, vitiates every contract; but in many cases relief is only to be had in Chancery. It investigates and relieves against misrepresentation, against contracts obtained by reason of any undue advantage—of the breach of confidence, of mistake under which one party laboured, and against contracts which could never have been made, unless both parties had been greatly mistaken; or, in other words, against contracts honestly made on a mistake of one or both, and which, on discovering the whole facts, it is against common justice to attempt to enforce. The law and the cases on this subject, are collected with skill and diligence by Judge Story, in his Treatise on Equity, and will be'found from page 127 to 149.

I have stated the course of proceeding in countries where there are distinct courts of l&w and equity, to show that decisions in a court of law in those countries do not show what is the event of a cause in which one phrty produces a formal deed and the other seeks to avoid it by proving actual or legal fraud, imposition, mistake, undue advantage, or want of consideration. In this state the same court disposes of the wh'ole case, and the result of a trial is the same as that of a suit in both courts in other countries. The rules as to parol evidence applied to written documents, have no application to cases in which relief is sought by proving any of the matters in equity above stated. Fraud, imposition, mistake, or total failure of consideration, must be proved by parol wholly or partly, or remain undetected.

I do not know how it happened, but it did happen that in the Common Pleas this cause was discussed by both parties as a contract prohibited by Act of Assembly. It was conceded here that there is no Act of Assembly on the subject; the form of the contracts is that adopted by the canal commissioners, and agreed to and sanctioned by the hands and seals of the parties; and it was proved by one of the canal commissioners, that although formerly underletting was permitted, the clause against assigning was in 1840 and since rigidly enforced. In this court the argument was on much broader ground. The contract was here attacked as void on many grounds—fraud, misrepresentation, concealment of the facts that Ramsey and Bishop had been urged to come on to commence the work, and the total mistake of both parties, or at least of Reed and M’Gee, that the contract had been declared abandoned.

There has been much written and more said as to whether a mistake of law will be ground for rescinding a contract. I have never known a case in which there were not other circumstances than mistake of law brought to the consideration of the court. Chancellor Kent supports the doctrine, but confines it to cases in which there is a full knowledge of all the facts and circumstances. 6 Johns. Ch. 169, 170. Judge Story seems to support the naked *265proposition, but says equity will relieve where there is an admixture of other ingredients going to establish misrepresentation, imposition, undue confidence, undue influence, mental imbecility, or that sort of surprise which equity uniformly regards as a just foundation for relief. 1 Story 132, 3. Modern cases seem to carry the exception further, to cases in which a person has been induced to give up a portion of his undisputed property and gets nothing in return. 1 Sim. Stewart 555, and cases cited 1 Story 139, as to mistake. Where parties have presupposed some facts or rights to exist as the basis of their proceeding, which in truth did not exist, such contracts made in mutual error, under circumstances material to their character and consequences, seem on general principles invalid. 1 Story 149, and notes. Lord Hardwicke, in Chesterfield v. Jansen, arranges among contracts which “will be relieved against, such bargains as no man in his senses and not under delusion, would make on one hand, and no honest and fair man would accept on the other hand.

The case of Quick v. Stuyvesant, (2 Paige 84), is full to the principle contended for by the defendants in this case. Parties had agreed and mutually conveyed to each other certain parcels of land, intending to lay it out in lots and streets, on what is now part of New York. In 1807 the legislature directed streets to be laid out in a manner entirely different from that proposed. The chancellor directed reconveyances. “ In all matters whatever,” says he, “ as well as matters of law, the end is the capital circumstance, and the means are regarded so far only as they contribute to that end. When a deed or obligation is sought to be made effectual in an event which is unexpected to both parties, a Court of Equity denies its authority. The party seeking to enforce it is unjust and inequitable in his demand, and this furnishes a valid objection to the adverse party. Where, from the defect of the common law, want of foresight of the parties, or mistake, or accident, there would be a failure of justice, it is the duty of this court to interfere and supply the defect or furnish the remedy.”

In this state we do not turn a party round to another court to obtain what plain and natural equity requires; and we say, on the facts adduced in this cause, admitting them to be as the plaintiff alleges, the judgment in the court below is affirmed.

Judgment affirmed.