(after stating the facts as above). The substance of plaintiff’s contention is that all the cars above referred to furnish iten* of damage properly assignable to its second cause of action.
But there is a secondary rule (Williston,' Cont. § 623) that interpretation may be given to a contract by the acts-and/or declarations of the parties, done or made while the agreement is in process of fulfillment, and before any differences have arisen-between them, to which “mutual’interpretation” (as Dean Wigmore has called it) courts strongly and properly incline to give effect. There' is room for applying this secondary (and always secondary) method to the situation presented by the 200'gondola cars, and we think it overwhelmingly proven that, as found below, the mutual interpretation given by the parties to this contract was that, when plaintiff had an opportunity to bid and did not avail itself of the same, both parties assumed and in effect agreed that plaintiff was to get royalties and nothing else.
This rule of mutual understanding must always be carefully subordinated to the primary rule of compelling parties to live up to what they have chosen to write, and is not to be confounded with attempts to vary a contract by parol, and this may be accomplished by stressing the mutuality of thp interpretation acted on by the contractors. It is nothing against this rule that sometimes the result is a finding equivalent to holding that the parties made a new contract, or modified the pre-existing one. Williston, supra. See, also, on the propriety of adopting the practical interpretation of parties, Sanders v. Munson,
«As ’ to the automobile cars, the finding below was as recited1 in our statement of facts. The facts as found bind us, and on them we see no reason to elaborate our decision as made in
Judgment affirmed, without costs.
