Iowa 617, 138 N.W.2d 918, 920 (1965) that:
“The reason for the [parol evidence] rule is that the parties have made their agreement, of which the written contract is evidence, and to permit additions or variances would be to change the terms of their agreement. Fidelity Savings Bank v. Wormhoudt Lumber Company of Ottumwa, 251 Iowa 1121, 1126, 104 N.W.2d 462, and citations.
“Simply, it is to prevent fraud and prevent contracting parties from being charged with agreements not in fact made.”
We agree with the trial court that the document here involved is clear on its face; if the parol evidence rule has any validity, we cannot allow appellant to rely on extrinsic evidence to modify a contract without ambiguity. See Aultman v. Meyers, 239 Iowa 940, 33 N.W.2d 400, 405 (1948).
But appellant insists that the Iowa law has been modified (as has that of some other jurisdictions), and that we cannot look solely at the language of the parties, i. e., the common and normal sense of the words, but must look at the intent with which the parties used those words. In other words, the claim is that “an unrestricted right to terminate” was intended by the parties to mean “a restricted right to terminate.”
Appellant, in short, relies on Wig-more’s “mutual standard,” as distinguished from (1) the “popular standard,” or (2) the “local standard,” or (3) the “individual standard.” 9 Wigmore on Evidence, 3d ed., §§ 2458-2478; 3 Corbin on Contracts, § 535; and more particularly, Hamilton v. Wosepka, 154 N.W.2d 164, 168 (Iowa 1967), and Keding v. Barton, 154 N.W.2d 172 (Iowa 1967).
Because of the large reliance by appellant on the Wosepka case, we think we should briefly consider it.
In the Wosepka case, the Supreme Court of Iowa approved the action of the trial judge in receiving oral testimony in evidence, not “for the purpose of varying the terms of a written instrument, [but] * for the purpose of interpreting it.” 154 N.W.2d at 167.
In Wosepka, the plaintiff was suing for additional salary. He was being paid $15,000 per year when the contract was executed. The contract provided: “said salary to be increased or decreased in proportion to the increase or decrease of the salary or salaries” (154 N.W.2d at 165) of Wosepka, Prouk and Chandler. Their salaries were thereafter increased to $15,000 per year from $7,000, $10,000 and $10,000, respectively.
“We believe,” said the Iowa court, “[that this fact] makes the emphasized portion of paragraph 4, supra, susceptible to more than one meaning. Was the increase or decrease to be proportionately in amount or percentage? Was it to be based on an average of the increase or decrease of all three defendants?” 154 N.W.2d at 167.
Thus, we find (see n. 2, supra) that the trial judge here, in considering the pleadings, exhibits, pre-trial order, stipulations, admissions, declarations, affidavits, etc., did precisely what the Iowa courts say he should have done; he “[gave] the contract the practical meaning placed upon it by the parties.” (Keding v. Barton, supra, 154 N.W.2d at 175.) Although he did not think the words “unrestricted right to terminate” ambiguous, he had before him for his consideration “[t]he practical construction placed upon a contract of doubtful meaning by the parties themselves (Wosepka, supra, 154 N.W.2d at 172.)
“Proof of the circumstances may make a meaning plain and clear when in the absence of such proof some other meaning may also have seemed plain and clear. Sometimes the circumstances proof of which is offered do not have any probative value and do not affect a meaning that is arrived at without them. When such is the case, such circumstances are immaterial. In other cases, the testimony of additional factors may not be believed by the trial court after it has been admitted, in which case the meaning of words