delivered the opinion of the court.

■ The penalty cannot be recovered in this case as liquidated damages. It was only intended by the parties as a security for the faithful performance of the contract.

The value of the land at the time of the breach of the contract ought not, as has been contended, to constitute the measure of damages, for such a rule applied here, would work this injustice. The plaintiff would obtain the value of the land, and would moreover hold Dorsey’s right and title, having obtained a conveyance for the same, and would be left in possession of the land. Some outstanding right to these lands existed in Campbell and Ritchie, but its precise nature and character does not distinctly appear. Rnderson was their original proprietor, who sold them to Campbell and Ritchie, and Chapman the agent of Campbell and Ritchie, sold them to Dorsey. The right, what*443ever it was, which Dorsey acquired under these contracts, was conveyed by deed to the plaintiff. These facts shew how essentially this case varies from the case of Cannell vs. M’Lean, 6 Harr. & Johns. 297. The rule laid down by the court below, as to the measure of damages, is the correct rule to be applied to this controversy. It completely secures the plaintiff, and indemnifies him against the defendant’s breach of the contract. We also concur with the court below in the opinion by them expressed, that the onus of proof in this respect, lies upon the plaintiff; for the plaintiff must always be prepared with proof to shew the extent of injury he may have sustained, by the breach of any contract, before he can he entitled to recover his measure of damages.

We perceive no error in the direction which the court gave to the jury, that they ought to deduct from the damages they should find, whatever sum of money remained in the hands of the plaintiff, on account of the purchase made by him of Dorsey. The doctrine held out by this opinion, is maintained and settled by the Court of Appeals, in the case of the Baltimore Insurance Company vs. McFadon, 4 Harr. & Johns. 31, in which the court have given a construction to the act of 1785, eh. 46, sec. 7, in relation to set off.

judgment affirmed.