The opinion of the Court was delivered by

That articles of agreement for the sale and purchase of lands are usually merged in the deed, is certainly true as a general proposition; but to this rule there are many exceptions. It clearly does not extend to the case of a mistake as to the quantity, where the property is sold by the acre, arising from the miscalculation of the parties; for this comes within the rule that equity will relieve, when an act is done or contract made under a mistake or ignorance of a material fact. No person can be presumed to be acquainted with all matters of fact, nor is it possible by any degree of vigilance in all cases to' acquire that knowledge; and for this reason a court of equity is liberal in granting relief to prevent injustice, where the party asking it cannot be charged with culpable negligence. In the case in hand, every care was taken to guard against error by referring the admeasurement to a person of known skill; and if the artist'had acted in the character of a judge, as in M’Manus v. M’Cullough, (6 Watts 359); Brown v. Cooper, (7 Watts 311); or The Monongahela Navigation Company v. Fenlon, (4 Watts & Serg. 205), it is conceded the award would be conclusive. And it would be the same if, as in Packer v. Grey, it was the settlement of a doubtful right. But when it is the performance of a mere ministerial duty, a mere error of the agent in the admeasurement, a different case is presented. As the mistake could without doubt be rectified before the deed was executed, we see nothing in the authorities or in principle to prevent it now, the contract being unexecuted in part, some of the purchase money remaining unpaid. This is a mistake, not ignorance of facts, not by themselyes,but another, whom the parties, when they selected him for that purpose, rationally supposed from his peculiar skill would certainly ascertain the true quantity; and on that supposition alone were the ..deed and the bonds to secure the purchase money given. The quantity of land the tract contained constitutes a material ingredient in the contract; and the *204error, it is admitted, is a mutual one, which disappoints the declared intention of both vendor and vendee. Both parties, it is true, are equally innocent; but it would be against conscience to insist on payment when the error is considered, and when no blame is properly imputable to any person. It falls, as we conceive,within that class of cases so frequently occurring, where equity relieves parties from the consequences of a mistake of a third person, as, for example, of a scrivener, in drawing the agreement.

Judgment affirmed.