The opinion of the Court was delivered by

An instrument of writing may be reformed, by proof of circumstances which occurred at the time of its execution, showing either fraud or mistake; but to set aside a solemn agreement between parties and convert it into an obligation of a different import, the evidence of fraud or mistake ought to be of what occurred at the execution, and should be clear, precise and indubitable. It would be error, as is held in Stine v. Sherk, (1 Watts Serg. 195), to submit a question of fraud or mistake to the jury upon slight, trivial, parol evidence. These are the well-established principles of law, which must be applied to each case as it arises. The evidence on which this defence rests seems to have been given without objection: at least none appears on the record. The plaintiff, however, contends that it was of such a nature, so uncertain and unsatisfactory, that the jury could not undertake to reform the bond, and that the court ought so to have instructed them. If the case depended on the evidence of the scrivener, there would be great force in the objection, for his testimony merely proves that the dispute was as to the mode and manner of securing the purchase money; the vendor insisting upon a judgment, the vendee contending that it should be secured by a mortgage on the purchased premises. The testimony of Porter, however, one of the obligors in the bond, gives the transaction a different complexion. He proves, as the court say, that the bonds and mortgage were given for the balance of the purchase money, and that Ihe agreement was, that the money was to come out of no other property but the property sold. Now, however irreconcileable this evidence may be with the fact of the execution of bonds accompanying the mortgage, whose legal operation is so different, the omission of the scrivener to insert so important a provision in the agreement, and the marked difference between his *77testimony and the testimony of Porter, the obligor, yet we think there is nothing in the case which would justify the court in withdrawing it from the jury, and undertaking to instruct them, as a matter of law, that the defendant had failed in his defence. The case depends on the degree of credit to be attached to the testimony of the two witnesses; for, if Porter is believed, it is the case of a mistake of the scrivener in omitting to put this essential part of the agreement in writing, which has always been held a ground of equitable relief. But supposing all the testimony to be true, what its legal effect may be is another question. It is necessary to inquire whether it is a defence to the action, or, in other words, whether the bond is a nullity or an agreement merely that none but the mortgaged premises shall be answerable for the-debt. And we think the latter to be the true construction of the contract, giving the testimony all the force to which it is justly entitled. Why may not the plaintiff have- two securities, one on his mortgage, and another and a better one on the bond, the judgment and execution to be controlled by the court, so as to prevent a levy on other than the mortgaged premises ? Indeed, it may be doubted whether, on any other principle, the evidence would be admissible, as there is a great difference between the destruction and the reform of an instrument of writing. It may be remarked that there is a substantial difference between the remedy on the bond and the mortgage. The latter cannot be sued out until a year after the last instalment is payable, whereas suit may be brought on the former when it becomes due.

Judgment reversed, and a venire de novo awarded.