¶1 The written contract was an unconditional promise to pay the plaintiff, or to his order, one thousand dollars. The evidence excepted to tended to vary this contract, and to show that the agreement between the parties was, that the sureties were not to pay the one thousand dollars if the plaintiff should loan the principal three thousand dollars more, and should secure that sum, and the one thousand (dollars represented by the note in suit, by a mortg’age upon certain real estate of the principal’s wife, and that the plaintiff had not carried out this agreement. This made an entirely different contract from that reduced to writing and declared on. The written contract Avas an unconditional promise to pay. The one which the parol evidence tended to prove was conditional and defeasible, upon the performance of a distinct collateral agreement between the plaintiff and the principal. Its tendency was, not to show that there Avas no consideration, or that there was a partial failure of consideration, but to import into it a condition of which the written contract furnished-no evidence. This agreement was contemporaneous with the note, and the evidence excepted to was in conflict with the rule which forbids the introduction of parol evidence to vary or control a written contract. Bank v. Rogers, 16 N. H. 9; Caldwell v. Porter, 17 N. H. 27, 30; Hunt v. Adams, 7 Mass. 518; Stackpole v. Arnold, 11 Mass. 27, 32; Hanson v. Stetson, 5 Pick. 506; Spring v. Lovett, 11 Pick. 417, 419; Myrick v. Dame, 9 Cush. 248; Billings v. Billings, 10 Cush. 178 ; Bank v. Dunn, 6 Pet. 51; Brown v. Wiley, 20 How. 442, 447, 448; Specht v. Howard, 16 Wall. 564; Forsythe v. Kimball, 91 U. S. 291, 274; Brown v. Spofford, 95 U. S. 474, 480; Ridout v. Bristow, 1 Cr. & J. 231; Foster v. Jolly, 1 Cr. M. & R. 703; Rawson v. Walker, 1 Stark. N. P. 361; Big. Bills and Notes, 173; 1 Dan. Neg. Ins. 35, 69, ss. 41, 80, 81.
¶2 Ver diet set aside.