It is believed, as insisted by appellant, that the evidence does not warrant the judgment in favor of the appellees. Contemporaneous with the execution of the nonnegotiable notes in evidence was a written agreement of the parties having the effect to make the payment of the note out of a special fund on a specified contingency, and not otherwise. The agreement of the parties to make the payment of the note subservient to the limitations and restrictions of such agreement is valid. Rogers v. Broadnax, 24 Tex. 538; National Bank v. Smith, 22 S.W. 1056. The payee was to accept and the maker to make payment of the notes "out of the damages" that might be recovered by L. H. Sides in his certain claim for damages founded on an alleged breach of agreement on the part of J. V. Wiggins to place L. H. Sides in possession of the land on January 1, 1912. But, as further stipulated, "in the event the court should hold that the said L. H. Sides is not entitled to recover any damage or money or offset on the note owed J. V. Wiggins by him," then the notes were not to be paid at all, but were to be canceled and surrendered to the maker; and it is believed that the evidence does not support the plaintiffs' allegation in the petition, in order to support the action, that L. H. Sides recovered and was allowed an offset against the vendor's lien in the suit on said notes by J. V. Wiggins. According to the evidence of the attorney representing Sides:
"L. H. Sides filed the defenses as set out in the contract to said suit by J. V. Wiggins, and they were urged before the court, but the court held they were not proper defenses to said suit on the $5,000 note, and such defenses were abandoned when the court so held. Mr. Sides then made settlement of the note."
And in the "settlement of the note" referred to it appears that the appellant paid $603.34 less than the principal, interest, and attorney's fees due under the terms of the vendor's lien note at the date of settlement. But this underpayment may not, in the evidence, be said to be, within the meaning of the contract, "a recovery by L. H. Sides" of that sum as "damage or money or offset on the note owed J. V. Wiggins by him." For, as clearly shown by the witness Cox, the underpayment of the $603.34 by L. H. Sides to J. V. Wiggins was inadvertent, and a mistake due solely to erroneous calculation by the parties of the amount then due on the note being settled. The witness Cox testified that:
"We figured and intended to pay the full amount of the note. * * * If the entire amount thus figured and paid was not the entire amount that the note came to, with compound interest, then it was a mistake, as we intended to pay that much."
Thus it is evident that, if the mistake in calculation had not occurred, the underpayment of the amount due would not have been made; and L. H. Sides would not have the right, in view of the mutual mistake, to retain the amount of underpayment, for J. V. Wiggins has, under such proof, ground for relief to recover such unpaid amount. Hummel v. Flores, 39 S.W. 309; Emerson v. Navarro, 31 Tex. 335, 98 Am.Dec. 534; Alston v. Richardson, 51 Tex. 1. And such evidence so far fails to show an "agreed reduction" of $603.34 from the vendor's lien note, so that it may not properly be said as a fact that L. H. Sides has received "damage or money or offset," within the meaning of the contract, on the vendor's lien note.
As the plaintiffs in the petition predicate a recovery upon the terms of the contract, and upon no other ground, a recovery, in the evidence, may not be allowed them. The judgment is reversed, and judgment is here entered for the appellant, with costs of the trial court and of this appeal.