¶1The reformation of written agreements, when, by mistake, they express more or less than the parties intended, is now a well established branch'.of equity jurisdiction, but if the proofs are doubtful and unsatisfactory, and the mistake is not entirely plain, equity will withhold relief on the ground that the written paper -ought to be treated as a full and correct expression of the intent, until the contrary is established beyond reasonable controversy. [1 Story’s Eq. § 152, and cases there cited.]
¶2If, as the counsel for the defendant supposes, the proof in this cause established the contract to be, that the complainant was to warrant the then condition of the slave,-it would admit of serious question, whether his mistaken impression that such a contract would not cover a constitutional defect subsequently developed, would be admitted to qualify the legal import of his agreement; but as we understand the evidence, no such inference is warranted. - Those present when the sale was made, are positive and precise in declaring the (contrac.t was, the slave should not be warranted sound, and ,the reason was then given by the'seller, why he would-not *191assume this obligation. The contract was then complete in all its terms, and nothing remained to be done by the purchaser than to pay the money, -or by the seller, than to execute the bill of sale. If the proof had stopped at this point, it is possible there would be no sufficient explanation .to account for the variance between the contract as agreed en, and that expressed by the receipt. There is no ground, however, to suppose the contract itself was afterwards varied by the parties, for the complainant himself caused the bill of safe to be prepared, and the testimony of the draftsmen is convincing that the warranty of soundness was inserted — not because there was any contract to that effect — but to guard the complainant against the precise difficulty which afterwards happened and which the bill of sale as drawn does not exclude. In our judgmenC.it is a case of mistake clearly within the rules previously stated, and the chancellor’s decree is substantially correct, though it might properly have gone farther and decreed the cancellation of this clause of the warranty.
¶3Decree affirmed.