Opinion by Hurt, J. § 550. Parol evidence not admissible to vary a written instrument. Parol evidence is not admissible to vary the plain and unambiguous language of a written instrument. The consideration for which the notes sued on were given, as shown by the notes, was a McCormick’s machine. There is no evidence in the record tending to show that the appellees attempted to return the machine within a'reasonable time. Because the court erred in admitting parol evidence to vary the written contract, and because there is no evidence to show a return in good faith within a reasonable time, the judgment is Reversed and remanded.